US 230

US 120

US 60

US 35

US 18

US 230

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2018–5147

Prepared in cooperation with the U.S. Army Corps of Engineers, New Orleans District

Revisions to Suspended-Sediment Concentration, 

Percent Smaller Than 0.063 Millimeter, and 

Instantaneous Suspended-Sediment Discharge 

Reported for a Cooperative Program 

Between the U.S. Geological Survey and 

the U.S. Army Corps of Engineers in the 

Lower Mississippi-Atchafalaya River Basin, 

October 1989 to February 2015
Front cover. Schematic showing the laboratory method used in the cooperative program between the U.S. Army Corps of Engineers and 

the U.S. Geological Survey in the lower Mississippi-Atchafalaya River Basin (illustration by L.S. Coplin, U.S. Geological Survey; modified from 

fig. 3).

Back cover. Photograph showing a U.S. Geological Survey laboratory technician at the Baton Rouge Sediment Laboratory processing

a water sample with the modified riffle splitter used to analyze cooperative program samples (photograph by Aimee Downs, U.S.

Geological Survey).
Revisions to Suspended-Sediment 

Concentration, Percent Smaller 

Than 0.063 Millimeter, and 

Instantaneous Suspended-Sediment Discharge 

Reported for a Cooperative Program 

Between the U.S. Geological Survey and 

the U.S. Army Corps of Engineers in the 

Lower Mississippi-Atchafalaya River Basin, 

October 1989 to February 2015

By Katherine K. Norton, Lisa D. Olsen, Todd E. Baumann, Lane B. Simmons, 

Athena P. Clark, Dennis K. Demcheck, and Marlon Johnson

Prepared in cooperation with the U.S. Army Corps of Engineers, 

New Orleans District

Scientific Investigations Report 2018–5147

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DAVID BERNHARDT, Secretary

U.S. Geological Survey

James F. Reilly II, Director

U.S. Geological Survey, Reston, Virginia: 2019

For more information on the USGS—the Federal source for science about the Earth,

its natural and living resources, natural hazards, and the environment—visit

http://www.usgs.gov/ or call 1–888–ASK–USGS (1–888–275–8747).

For an overview of USGS information products, including maps, imagery, and publications,

visit http://www.usgs.gov/pubprod/.

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Norton, K.K., Olsen, L.D., Baumann, T.E., Simmons, L.B., Clark, A.P., Demcheck, D.K., and Johnson, M., 2019, Revisions 

to suspended-sediment concentration, percent smaller than 0.063 millimeter, and instantaneous suspended-sediment 

discharge reported for a cooperative program between the U.S. Geological Survey and the U.S. Army Corps of 

Engineers in the lower Mississippi-Atchafalaya River Basin, October 1989 to February 2015: U.S. Geological Survey 

Scientific Investigations Report 2018–5147, 232 p., https://doi.org/10.3133/sir20185147.

ISSN 2328-031X (print)

ISSN 2328-0328 (online)

ISBN 1-4113-4290-3
iii

Acknowledgments

The authors would like to extend our deep gratitude to Eric Glisch, U.S. Army Corps of Engineers 

Mississippi Valley Division, New Orleans District (USACE MVN), for his assistance in recovering 

digital and physical files critical to the production of this report. Additionally, Barbara Kleiss, 

USACE Mississippi Valley Division, was instrumental in providing financial support for the 

preparation of this report. We also received help uncovering elements of the program history 

from Nancy Powell, USACE MVN (retired), and David Biedenharn, USACE Engineer Research and 

Development Center. 

Within the U.S. Geological Survey (USGS), Aimee Downs (Kentucky Water Science Center 

Sediment Laboratory), Dan Gooding (Cascades Volcano Observatory Sediment Laboratory), and 

Cheryl Joseph (Lower Mississippi-Gulf Water Science Center [LMGWSC] Baton Rouge Sediment 

Laboratory) helped with the physical testing of the sample splitter in August 2015 and provided 

many other valuable insights into laboratory processes. Mark Landers, Federal Interagency 

Sedimentation Project Chief, oversaw the review during critical early stages and organized 

the targeted concurrent sampling event; his many insightful comments and clear leadership 

were instrumental in accomplishing the review and revision. Christina Bartlett, Chief of the 

Information Management Branch, and her staff spent many hours entering laboratory data 

into spreadsheets and scanning original paper forms. Ron Seanor, Darlene Smothers, and Burl 

Goree from the LMGWSC data section assisted with the many requests for data retrievals and 

data changes in USGS information systems. Claire Rose of the LMGWSC provided geographic 

information system support for the site map. Jennifer Murphy and Scott Mize of the LMGWSC 

assisted with the review of instantaneous discharge values. Shannon Williams, LMGWSC Data 

Chief, reviewed the regression model for discharge at Union Point, Louisiana, and provided 

thoughtful feedback on the project at many stages. 

v

Contents

Acknowledgments .......................................................................................................................................iii

Abstract ..........................................................................................................................................................1

Introduction ....................................................................................................................................................1

Problem Statement ..............................................................................................................................2

Purpose and Scope .............................................................................................................................2

Description of the Cooperative Program ..................................................................................................7

Cooperative Program History ............................................................................................................7

Site Locations .......................................................................................................................................8

Sampling Design ..................................................................................................................................8

Field Methods .......................................................................................................................................9

Laboratory Analysis Methods ..........................................................................................................10

Data Flow and Information Systems Methods ..............................................................................12

Computations ......................................................................................................................................13

Reporting .............................................................................................................................................17

Critical Review of Field, Laboratory, and Computational Protocols ...................................................17

Sampling Design Review ..................................................................................................................18

Discharge-Weighted Average SSC .......................................................................................18

Daily Suspended-Sediment Load ...........................................................................................18

Field Methods Review .......................................................................................................................19

Laboratory Analysis Review .............................................................................................................20

Dissolved Solids ........................................................................................................................20

Particle-Size Distribution .........................................................................................................22

Subsampling ..............................................................................................................................22

Laboratory Method Performance ..........................................................................................22

Information Systems Review ...........................................................................................................22

Computations Review .......................................................................................................................23

Reporting Review ...............................................................................................................................24

Methods Used To Revise Results .............................................................................................................24

Candidate Methods for Dissolved-Solids Correction ..................................................................24

Preparation of Test Samples ............................................................................................................25

Internally Prepared Test Samples ..........................................................................................25

Externally Prepared Test Samples .........................................................................................25

Physical Testing .................................................................................................................................25

Revised Suspended-Fines Concentration Computation ..............................................................26

Revised Suspended-Sand Concentration Computation ..............................................................27

Revised SSC Computation ................................................................................................................27

Estimation of Laboratory Uncertainty .............................................................................................27

Historical Sediment Data ..................................................................................................................30

Instantaneous Stream Discharge ...................................................................................................32
vi

Corrected SSC and Related Results ........................................................................................................33

Change in Reported SSC ..................................................................................................................34

Uncertainty of SSC ...................................................................................................................35

Change in Reported Percent Fines .................................................................................................36

Change in Reported Instantaneous Stream Discharge ...............................................................36

Change in Reported Suspended-Sediment Discharge ................................................................38

Change in Suspended-Sand Discharge .........................................................................................39

Change in Population-Scale Summary Statistics .........................................................................40

Critical Evaluation of Revised Results .....................................................................................................43

Effect of SSC Computation Method ................................................................................................43

Suspended-Sand Concentration ............................................................................................43

Suspended-Fines Concentration ............................................................................................44

Effect of Laboratory Practices on Revised Suspended-Fines Concentrations .......................44

Information About Bias and Uncertainty in Revised SSC ...........................................................46

Conclusions ..................................................................................................................................................46

References Cited .........................................................................................................................................47

Appendix 1. U.S. Army Corps of Engineers (USACE) FORTRAN source code for modules 

used to process laboratory results and compute suspended-sediment load 

for a cooperative program between the U.S. Geological Survey and the 

USACE in the lower Mississippi-Atchafalaya River Basin from 1973 to 

February 2015 ......................................................................................................................49

Appendix 2. Example laboratory data sheet used for recording laboratory results for a 

cooperative program between the U.S. Geological Survey and the U.S. Army 

Corps of Engineers in the lower Mississippi-Atchafalaya River Basin from 

1973 to 2001, which also served as the basis for the Excel spreadsheet that 

was used from 2001 to February 2015 ...........................................................................127

Appendix 3. Example 80-column text file (SED file) used as input to the U.S. Army Corps of 

Engineers (USACE) FORTRAN modules that computed suspended-sediment 

concentration, particle-size distribution, and suspended-sediment discharge 

for a cooperative program between the U.S. Geological Survey and the 

USACE in the lower Mississippi-Atchafalaya River Basin from 1973 to 

February 2015 ....................................................................................................................131

Appendix 4. Corrected and original results for instantaneous stream discharge, 

suspended-sediment concentration, suspended-sediment percent smaller 

than 0.0625 millimeter, and suspended-sediment discharge for water samples 

collected from select sites in the lower Mississippi-Atchafalaya River Basin .....135

Figures

1. Map showing the study area and station locations on the lower Mississippi 

River and Atchafalaya River for a cooperative program between the U.S. Army 

Corps of Engineers (USACE) and the U.S. Geological Survey (USGS) in the lower 

Mississippi-Atchafalaya River Basin that has been active since 1973 ..............................3

2. Diagram showing the flow direction, hydrologic nodes, and sites in the lower 

Mississippi-Atchafalaya River Basin sampled as part of the cooperative 

program between the U.S. Army Corps of Engineers and the U.S. Geological 

Survey ............................................................................................................................................5
vii

3. Diagram showing the laboratory method, including the wet sieve/split, “half 

fines,” dry sieve, and bottom-withdrawal (BW) tube analysis steps, used in the 

cooperative program .................................................................................................................11

4. Photograph showing a U.S. Geological Survey laboratory technician at the 

Baton Rouge Sediment Laboratory processing a water sample with the modified 

riffle splitter used to analyze cooperative program samples .............................................12

5. Graph showing an example graph used to review sand concentrations in crosssectional context for samples collected for the cooperative program between 

October 1989 and February 2015 in the lower Mississippi-Atchafalaya River 

Basin ............................................................................................................................................32

6. Boxplot showing relative bias in reported suspended-sediment concentration for 

samples collected for the cooperative program between October 1989 and 

February 2015 in the lower Mississippi-Atchafalaya River Basin .....................................35

7. Boxplot showing absolute change in percent fines for samples collected 

between October 1989 and February 2015 for the cooperative program in the 

lower Mississippi-Atchafalaya River Basin ..........................................................................37

8. Boxplot showing revised instantaneous stream discharge from measurements 

that were made concurrently with cross-sectional suspended-sediment samples 

at each site in the lower Mississippi-Atchafalaya River Basin for the periods of 

revised record, October 1989 through February 2015 ..........................................................39

9. Boxplot showing absolute change between the revised values and the originally 

reported values of instantaneous suspended-sediment discharge for samples 

collected between October 1989 and February 2015 for the cooperative program 

in the lower Mississippi-Atchafalaya River Basin ...............................................................40

10. Boxplot showing absolute change in the computed instantaneous suspendedsand discharge for samples collected between October 1989 and February 2015 

for the cooperative program in the lower Mississippi-Atchafalaya River Basin ............41

11. Graph showing the difference in the masses recovered from the bottomwithdrawal tube and “half fines” analyses, mdif, over time ................................................45

Tables

1. Site codes, station numbers, and sampling periods for nine sites included in a 

cooperative program between the U.S. Army Corps of Engineers and the 

U.S. Geological Survey in the lower Mississippi-Atchafalaya River Basin that 

has been active since 1973 ........................................................................................................4

2. Publicly available online data sources for retrieving revised results and 

metadata, and publicly available online data sources that contain results 

superseded by this report ..........................................................................................................6

3. Fields used in the laboratory data sheet transcribed by either the U.S. Army Corps 

of Engineers or the U.S. Geological Survey into an 80-column text file for input 

into the USACE FORTRAN software or to evaluate and compute the corrected 

results for samples collected between October 1989 and February 2015 for the 

cooperative program in the lower Mississippi-Atchafalaya River Basin ........................14

4. Comparison between discharge-weighted average and numerical average 

suspended-sand concentration, suspended-fines concentration, and suspendedsediment concentration for 913 events for which data were available for samples 

collected between October 1989 and February 2015 for the cooperative program 

in the lower Mississippi-Atchafalaya River Basin ...............................................................19
viii

5. Results from physical testing of the splitter used in the U.S. Geological Survey 

Baton Rouge Sediment Laboratory to process samples collected for the 

cooperative program in the lower Mississippi-Atchafalaya River Basin ........................28

6. Logical checks performed against final sample data with structured query 

language (SQL) queries to identify possible transcription errors in data recorded 

for samples collected between October 1989 and February 2015 for the cooperative 

program in the lower Mississippi-Atchafalaya River Basin ...............................................31

7. Summary statistics for the relative bias in suspended-sediment concentration 

and the absolute change in suspended-sediment concentration by site and 

bottle type for samples collected between October 1989 and February 2015 for 

the cooperative program in the lower Mississippi-Atchafalaya River Basin ..................36

8. Summary statistics for the absolute change in reported percent fines by site and 

bottle type for samples collected between October 1989 and February 2015 for the 

cooperative program in the lower Mississippi-Atchafalaya River Basin ........................37

9. Summary statistics for the relative bias in suspended-sediment discharge, the 

absolute change in suspended-sediment discharge, and the relative change in 

suspended-sediment discharge by site for samples collected between October 

1989 and February 2015 for the cooperative program in the lower MississippiAtchafalaya River Basin ...........................................................................................................38

10. Summary statistics for the absolute change in suspended-sand discharge by 

site for samples collected between October 1989 and February 2015 for the 

cooperative program in the lower Mississippi-Atchafalaya River Basin ........................41

11. Population-scale summary statistics for original and revised results for 

suspended-sediment concentrations for samples collected between October 

1989 and February 2015 for the cooperative program in the lower MississippiAtchafalaya River Basin ...........................................................................................................42

12. Population-scale summary statistics for original and revised results for 

suspended-sediment discharge for samples collected between October 1989 and 

February 2015 for the cooperative program in the lower Mississippi-Atchafalaya 

River Basin ..................................................................................................................................42

13. Linear regression models between composite suspended-sand concentration 

and average suspended-sand concentration for the 830 cross-sectional 

samples collected since October 1, 2005, for which revised suspended-sand 

concentration is reported for samples collected for the cooperative program 

in the lower Mississippi-Atchafalaya River Basin ...............................................................43
ix

Conversion Factors

U.S. customary units to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

inch (in.) 25.4 millimeter (mm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square foot (ft2) 929.0 square centimeter (cm2)

square foot (ft2) 0.09290 square meter (m2)

Volume

pint (pt) 0.4732 liter (L) 

cubic foot (ft3) 28.32 liter (L) 

quart (qt) 0.9464 liter (L) 

Flow rate

foot per second (ft/s) 0.3048 meter per second (m/s)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Mass

ton, short [2,000 lb] 0.9072 metric ton (t)

International System of Units to U.S. customary units

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

Volume

liter (L) 2.113 pint (pt)

liter (L) 1.057 quart (qt)

liter (L) 0.2642 gallon (gal)

cubic meter (m3) 264.2 gallon (gal) 

liter (L) 0.03531 cubic foot (ft3) 

Mass

gram (g) 0.03527 ounce, avoirdupois (oz)

kilogram (kg) 2.205 pound avoirdupois (lb)

metric ton (t) 1.102 ton, short [2,000 lb]

Density

gram per cubic centimeter (g/cm3) 62.4220 pound per cubic foot (lb/ft3) 
x

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as °F = (1.8 × 

°C) + 32°.

Concentrations of sediment are reported in units of milligrams of sediment per liter of watersediment mixture. Instantaneous suspended-sediment discharge is reported in short tons per 

day. A standard conversion factor of 0.0027 s × L × short tons × day-1 × ft-3 × mg-1 is used when 

computing instantaneous suspended-sediment discharge in tons per day as the product of 

suspended-sediment concentration in milligrams per liter and stream discharge in cubic feet 

per second. The conversion factor is computed from other standard conversion factors:

86,400 seconds/day × 28.32 L/ft3 × 1.102 × 10-9 short tons/mg

Particle-size distributions are reported in percent by mass of the sediment in a sample that is 

finer than the stated cutoff diameter, or “percent finer.” 

Abbreviations

ADCP acoustic Doppler current profiler

BW bottom withdrawal

CVO Cascades Volcano Observatory

DI deionized

FISP Federal Interagency Sedimentation Project

MVN Mississippi Valley Division, New Orleans District

NASQAN National Stream Quality Accounting Network

NWIS National Water Information System

ORCC Old River Control Complex

QSB Quality Systems Branch

QWDATA water-quality data (discrete) module of NWIS

SLQA Sediment Laboratory Quality Assurance

SSC suspended-sediment concentration

TDS total dissolved solids

USACE U.S. Army Corps of Engineers

USGS U.S. Geological Survey
Revisions to Suspended-Sediment Concentration, 

Percent Smaller Than 0.063 Millimeter, and 

Instantaneous Suspended-Sediment Discharge 

Reported for a Cooperative Program Between the 

U.S. Geological Survey and the U.S. Army Corps of 

Engineers in the Lower Mississippi-Atchafalaya 

River Basin, October 1989 to February 2015

By Katherine K. Norton, Lisa D. Olsen, Todd E. Baumann, Lane B. Simmons, Athena P. Clark, 

Dennis K. Demcheck, and Marlon Johnson

Abstract

This report presents revised results for four parameters 

reported for suspended-sediment samples that were collected 

in the lower Mississippi-Atchafalaya River Basin as part 

of a cooperative program between the U.S. Army Corps of 

Engineers, Mississippi Valley Division, New Orleans District 

and the U.S. Geological Survey (USGS). The cooperative 

program has been active since 1973 at seven sites: two sites 

on the main stem of the Mississippi River, three sites on the 

Atchafalaya River, one site on the Old River Outflow Channel, 

and one site on the lower Red River above the confluence 

with the Old River Outflow Channel. The four parameters—

suspended-sediment concentration, percent by mass of the 

sediment that passes through a 0.063-millimeter (US 230) 

sieve, instantaneous stream discharge, and instantaneous 

suspended-sediment discharge—reported for 2,895 samples 

have been modified to reflect the findings of a full review 

of the cooperative program, which was initiated by both 

agencies in January 2015. The revised results are for samples 

collected from October 1989 through February 2015. Ninetyfour percent of the revised values for suspended-sediment 

concentration are lower than their corresponding original 

reported values, indicating that less suspended sediment 

moves through the lower Mississippi River system than 

was previously reported. For example, the median revised 

instantaneous suspended-sediment discharge at the Mississippi 

River at Tarbert Landing, Miss. (USGS station 07295100), 

was 315,000 short tons per day, compared to 378,000 short 

tons per day as originally reported. At the Atchafalaya River 

at Simmesport, La. (USGS station 07381490), the median 

revised suspended-sediment discharge was 105,000 short 

tons per day, compared to 143,000 short tons per day as 

originally reported. The systematic downward revision in 

instantaneous suspended-sediment discharge values was due 

to a systematic downward revision in the suspended fine (less 

than 0.063 millimeter) sediment concentration. The effect 

of the revision on the suspended-sand concentration and 

instantaneous suspended-sand discharge was weaker. Any 

model of sediment load or transport processes in the basin that 

uses data from the affected samples should be reevaluated on 

the basis of the revised results. 

Introduction

Understanding sediment transport is critical to an 

effective understanding of hydraulic and environmental 

processes in fluvial ecosystems. Sediment transport studies 

rely on high-quality, accurate measurements of stream 

discharge, suspended-sediment concentration (SSC), and 

particle-size distribution to compute sediment loads (Koltun 

and others, 2006; Porterfield, 1972) and to model erosion, 

transport, and deposition in river systems (for example, 

Hydrologic Engineering Center-River Analysis System [HECRAS], Brunner, 2016). 

Sediment transport in the lower Mississippi-Atchafalaya 

River Basin is of national importance because of the need 

to maintain navigation and flood control along the Nation’s 

central commercial waterway (Ngyuen and others, 2011), as 

well as manage sediment delivery to flood plains and coastal 

wetlands in the region (Allison and others, 2012; Thorne 

and others, 2008). The importance of these concerns has 

long placed Mississippi-Atchafalaya River Basin sediment 
2 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

transport within the purview of the Federal Government. 

Specifically, the U.S. Army Corps of Engineers (USACE) is 

responsible for engineering and maintenance of the Old River 

Control Complex (ORCC). The ORCC prevents the lower 

Mississippi River from changing course and being captured 

by the Atchafalaya River (Heath and others, 2015), which has 

a steeper hydraulic gradient and shorter path to the Gulf of 

Mexico (fig. 1). 

The ORCC is designed to maintain the flow of water 

between the Mississippi and Atchafalaya River system in 

a proportion similar to that which occurred in the early 

1950s. This objective is operationalized by managing 

the ORCC so that 70 percent of the combined Red River 

and Mississippi River latitude flow above the ORCC 

discharges through the Mississippi River and 30 percent of 

the latitude flow discharges through the Atchafalaya River 

on a daily basis (Heath and others, 2015). Engineering and 

management decisions at the ORCC affect, and are affected 

by, sedimentation dynamics in the region (Heath and others, 

2015). Managing the stream discharge and sediment requires 

an understanding of the sediment transport processes.

Since 1973, the USACE Mississippi Valley Division, 

New Orleans District (MVN) and the U.S. Geological Survey 

(USGS) have conducted a cooperative program to monitor 

suspended-sediment transport in the lower MississippiAtchafalaya River Basin that provides the hydrologic and 

sediment data to support the USACE management of the 

ORCC. The agreement that defines the cooperative program is 

between the USACE MVN and the USGS Lower MississippiGulf Water Science Center (LMGWSC). Prior to the creation 

of the LMGWSC in 2014 the cooperative agreement was 

between the USACE MVN and the USGS Louisiana Water 

Science Center, which was incorporated into the LMGWSC 

along with water science centers from four other States. For 

brevity, the term “cooperative program” is used to refer to this 

partnership throughout this report. 

The cooperative program collects suspended-sediment 

and stream discharge data at seven hydrologic nodes, 

represented by nine sampling locations, in the lower 

Mississippi-Atchafalaya River Basin (fig. 1, table 1). The 

hydrologic nodes are points above and below important 

confluences in the region (fig. 2). Abbreviations (or codes) 

used in this report to refer to the hydrologic nodes and the 

sampling stations are defined in table 1.

Problem Statement

In 2006, the USGS National Stream Quality Accounting 

Network (NASQAN) program began monitoring water 

quality, including SSC, at two sites on the Atchafalaya River 

(WLO, MCY) that were also monitored by the cooperative 

program (fig. 1). The NASQAN program used depthintegrated equal width increment (EWI) sampling (Edwards 

and Glysson, 1999) to collect suspended-sediment samples. 

Because USGS field crews also visited the two sites to collect 

sediment samples for the cooperative program, the samples for 

both the NASQAN program and the cooperative program were 

frequently collected on the same day. 

Although the two programs differed in their respective 

goals and protocols, samples collected at the same station 

on the same day were expected to produce similar SSC with 

no systematic differences in values. However, cooperative 

program samples consistently produced higher SSC, and 

consequently higher estimates of instantaneous suspendedsediment discharge, than did the NASQAN program samples. 

In 2015, the USACE and USGS initiated a full review of the 

cooperative program, encompassing the protocols for the 

collection and handling of samples, laboratory procedures, and 

computation of SSC and related parameters. The purpose of 

the review was to determine the cause of the discrepancy in 

SSC data produced by the two programs. 

The review team compared the methods used by the 

cooperative program to current USGS policies and methods. 

The cooperative program was not designed to implement 

USGS methods, nor was its design revised as USGS methods 

changed over time. However, the USGS personnel conducting 

the review were required to implement current practices 

for data review and dissemination; the team also believed 

that comparing past practices to current laboratory and field 

practices would lead to improved data quality. During the 

review, the team determined that the cooperative program 

produced SSCs that were biased high relative to the true 

values and that sufficient laboratory metadata existed to 

compute more accurate SSCs for samples collected for the 

cooperative program.

Purpose and Scope

The purpose of this report is to present revised results 

for four parameters reported for 2,895 suspended-sediment 

samples collected as part of the cooperative program in the 

lower Mississippi-Atchafalaya River Basin from October 

1989 through February 2015. Revised results for samples 

collected from 1973 through September 1989 are beyond the 

scope of this report. This report presents revised values of 

SSC, percent by mass of the sediment that passes through a 

0.063-millimeter (mm) sieve (US 230 sieve), instantaneous 

stream discharge, and instantaneous suspended-sediment 

discharge. The term “fines” is used throughout this report to 

refer to sediment that passes through the 0.063-mm sieve; 

the term “percent fines” is used to refer to the percent by 

mass of the suspended sediment that passes through the 

0.063-mm sieve. The term “stream discharge” is used to 

distinguish between the discharge of water in the stream and 

the suspended-sediment discharge. Stream discharge is also 

commonly called “streamflow” or, simply, “discharge.” The 

purpose of the revision is to provide more accurate values 

for the aforementioned parameters, which are reported to the 

USGS discrete water-quality database, QWDATA. 
Base from U.S. Geological SurveyNational Hydrography DatasetUniversal Transverse Mercator, zone 15NNorth American Datum of 1983

0 20 40 MILES

0 20 40 KILOMETERS

Lake

Pontchartrain

Atchafalaya

River Mississippi River

GULF OF MEXICO

LOUISIANA

MISSISSIPPI

WLO

MCY

BRG

STF

MEL

RRL

RDR

SIM

TAR

ORO2

ORO1

UPT1

UPT2

BLC

WLO

MCY

BRG

STF

MEL

RRL

RDR

SIM TAR

ORO2

ORO1

UPT1

UPT2

BLC

New Orleans

Melville

Simmesport

Morgan City

Baton Rouge

EXPLA

Inactive water-quality Active water-quality s

inactive site for the 

Active water-quality s

active site for the N

Stage measurement siInactive water-quality 

program 

Active water-quality sActive water-quality s

RDR

STF

BRG

WLO

MCY

RRL

ORO2

92° 91° 90° 89°

31°

30°

Figure 1. The study area and station locations on the lower Mississippi River and Atchafalaya River for a cooperative program between the U.S. Arm(USACE) and the U.S. Geological Survey (USGS) in the lower Mississippi-Atchafalaya River Basin that has been active since 1973. Station labels for ththis study—UPT1, UPT2, TAR, ORO1, ORO2, RDR, SIM, WLO, and MCY—correspond to points described in table 1. Four additional USGS stations are in(07373420), MEL (07381495), BRG (07374000), and BLC (07374525). Results from these four stations are not affected by the revisions presented in this restation at Red River Landing (RRL; 01120) is also shown because it is the location of the gage that is used to compute stream discharge at Tarbert LandNational Stream Quality Accounting Network, a USGS program.
4 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 1. Site codes, station numbers, and sampling periods for nine sites included in a cooperative program between the U.S. Army 

Corps of Engineers (USACE) and the U.S. Geological Survey (USGS) in the lower Mississippi-Atchafalaya River Basin that has been 

active since 1973. 

[Information about sampling prior to 1977 was taken from Keown and others (1977). The seven sites are represented by nine stations because the sampling 

locations for two of the sites (ORO, UPT) were moved during the study period. USGS, U.S. Geological Survey; USACE, U.S. Army Corps of Engineers; 

WY, water year; LA, Louisiana; MS, Mississippi]

Site 

code1

Sampling 

location 

code2

(fig. 1)

Station name USGS station 

number

USACE 

station 

number3

Sediment sampling 

period WY (agency) 

Mississippi River

UPT UPT1 Mississippi River at Coochie, LA 310552091361200 01020 1962–73 (USACE)

1975–91 (USACE)

UPT UPT2 Mississippi River at Union Point (Mile 326) 07295025 01020 1991–present (USACE)

TAR TAR Mississippi River at Tarbert Landing, MS 07295100 01100/

01100Q

1963–present (USACE)

Old River Outflow Channel

ORO ORO1 Old River Outflow Channel near Knox Landing 310355091411500 02600 1963–2009 (USACE)

ORO ORO2 Old River Outflow Channel below hydropower 

channel

07381482 02600/ 

02600Q

2010–present (USGS)

Red River

RDR RDR Red River above Old River Outflow Channel 

above Simmesport

310408091424500 04800 1963–2005 (USACE)

Atchafalaya River

SIM SIM Atchafalaya River at Simmesport, LA 07381490 03045/

03045Q

1952–2009 (USACE)

2010–present (USGS)

WLO WLO Wax Lake Outlet at Calumet, LA 07381590 03720 1973–present (USGS)

MCY MCY Lower Atchafalaya River at Morgan City, LA4 07381600 03780 1973–present (USGS)

1

The three-letter site codes are a convention used only in this report. The site code is assigned to the hydrologic node represented by the sampling location.

2

These sampling location codes are used only for this report; they are used to clarify the sampling location during different periods over the course of the 

history of the cooperative program.

3

USACE station numbers that end with a Q are used to report daily discharge at a sampling location.

4

At MCY, periodic sand deposition is observed near the left bank; the sand bar that forms is periodically dredged to maintain the open channel into a ship yard 

on the left bank.

The USGS uses parameter codes to define physical 

properties when reporting results to QWDATA. SSC in 

milligrams per liter is reported on USGS parameter code 

(p) 80154. Percent fines in percent is reported on p70331. 

Instantaneous stream discharge in cubic feet per second 

is reported on p00061. Instantaneous suspended-sediment 

discharge in short tons per day is reported on p80155. 

There is a small apparent discrepancy for the percent fines 

between the formal name of p70331, “suspended sediment, 

sieve diameter, percent smaller than 0.0625 millimeters,” 

and the stated 0.063-mm opening size on the US 230 sieve. 

The American Society for Testing and Materials E-11 

standard states that the average opening of the US 230 sieve 

is 0.063±0.0037 mm (American Society for Testing and 

Materials, 2014). The physical difference between 0.0625 mm 

and 0.063 mm is not resolvable using current sieve standards, 

so 0.063 mm and 0.0625 mm are treated as though they are 

equivalent in this report. 

This report includes the following elements:

• A description of the cooperative program, including 

the program’s history, sampling design, and field, 

laboratory, and computational protocols;

• Details of the review findings comparing the 

cooperative program to USGS policies and practices; 

• Detailed descriptions of methods used to compute 

revised SSC and percent fines, including consideration 

of alternative approaches, preparation and analysis of 

test samples, computation of corrected SSC and related 

parameters, and uncertainty analysis; and

• Results of a data correction presented in terms of 

the resulting change in reported values for SSC, 

percent fines, instantaneous stream discharge, and 

instantaneous suspended-sediment discharge.
Introduction 5

Lake

Pontchartrain

GULF OF MEXICO

Atchafalaya River

Red River

Mississippi River

New Orleans

Baton Rouge

Old River Outflow Channel

NOT TO SCALE

Old River Control Complex 

EXPLANATION

Flow direction

USGS-USACE program site and code—ORO 

and UPT each sampled at two locations 

through program history

ORO

UPT

WLO MCY

RDR

SIM TAR

SIM

LOUISIANA

MISSISSIPPI

Figure 2. The flow direction, hydrologic nodes, and sites in the lower Mississippi-Atchafalaya River Basin sampled as part of the 

cooperative program between the U.S. Army Corps of Engineers (USACE) and the U.S. Geological Survey (USGS). The UPT and ORO 

nodes were each sampled at two different locations during the program (table 1).

The revised results for all four parameters are publicly 

hosted through the USGS National Water Information System 

(NWIS) web interface, NWISWeb (U.S. Geological Survey, 

2018), for “water quality: field/lab samples” (table 2). 

Supporting information about site hydrology can also be found 

on NWISWeb (U.S. Geological Survey, 2018) and through the 

USACE Rivergages website (U.S. Army Corps of Engineers, 

2017). Data that support the findings of the comprehensive 

review are publicly available in Norton and others (2019). 

Norton and others (2019) contains a machine-readable listing 

of the original and revised values for each cross-sectional 

sample, along with the values recorded for all phases of 

the laboratory analysis and supporting field metadata for 

individual bottles used to collect the cross-sectional samples. 

Cooperative program data that were collected prior 

to October 1989 have been removed from public view on 

NWISWeb (U.S. Geological Survey, 2018) because they 

are known to have been produced with a biased method. 

The suspended-sediment data, including daily suspendedsediment loads, were also published in USGS Water-Year 

Summaries (2006–13) and Water-Data Reports (1973–2005) 

for the affected stations (table 2). These reports have been 

watermarked in the USGS-hosted online repositories to reflect 

the fact that the data are superseded by the data in this report. 

Data users that rely on local copies of printed reports should 

be aware that the suspended-sediment data produced by the 

cooperative program are no longer considered reliable on the 

basis of the findings of the review documented in this report.
6 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 2. Publicly available online data sources for retrieving revised results and metadata, and publicly available online data sources 

that contain results superseded by this report.—Continued

[Stations are organized in order approximately upstream to downstream. Printable reports available through U.S. Geological Survey (USGS) online repositories 

have been watermarked to reflect the findings presented in this report. Data users that rely on local copies of printed reports should be aware that the suspendedsediment data in the Water-Data Reports for these stations are no longer considered reliable. Printed Water-Data Reports for samples before 2003 are not 

available online but are also deprecated by this report. NWIS, USGS National Water Information System database; QWDATA, a database within NWIS that 

contains results of discrete water-quality samples; USACE, U.S. Army Corps of Engineers; URL, uniform resource locator] 

Sampling location code1 URL

Revised suspended-sediment data: NWIS-QWDATA (water quality: field/lab samples)

UPT1 https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=310552091361200

UPT2 https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07295025

TAR https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07295100

ORO1 https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=310355091411500

ORO2 https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07381482

RDR https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=310408091424500

SIM https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07381490

WLO https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07381590

MCY https://nwis.waterdata.usgs.gov/usa/nwis/qwdata?site_no=07381600

USGS stream discharge field measurements: NWIS-FieldMeasurements (surface water: field measurements)

ORO2 https://nwis.waterdata.usgs.gov/usa/nwis/measurements?site_no=07381482

SIM https://nwis.waterdata.usgs.gov/usa/nwis/measurements?site_no=07381490

WLO https://nwis.waterdata.usgs.gov/usa/nwis/measurements?site_no=07381590

MCY https://nwis.waterdata.usgs.gov/usa/nwis/measurements?site_no=07381600

USGS stream discharge time series: NWIS-UnitValues (time-series: current/historical observations)

ORO2 https://nwis.waterdata.usgs.gov/usa/nwis/uv?site_no=07381482

SIM https://nwis.waterdata.usgs.gov/usa/nwis/uv?site_no=07381490

WLO https://nwis.waterdata.usgs.gov/usa/nwis/uv?site_no=07381590

MCY https://nwis.waterdata.usgs.gov/usa/nwis/uv?site_no=07381600

USACE once-daily stream discharge: Rivergages.com 

TAR http://rivergages.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=01100Q&fid=&dt=S

ORO http://rivergages.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=02600Q&fid=&dt=S

SIM http://rivergages.mvr.usace.army.mil/WaterControl/stationinfo2.cfm?sid=03045Q&fid=&dt=S

Superseded online Water-Year Summary Reports (2006–13)2

ORO2 https://nwis.waterdata.usgs.gov/usa/nwis/wys_rpt?site_no=07381482

SIM https://nwis.waterdata.usgs.gov/usa/nwis/wys_rpt?site_no=07381490

WLO https://nwis.waterdata.usgs.gov/usa/nwis/wys_rpt?site_no=07381590

MCY https://nwis.waterdata.usgs.gov/usa/nwis/wys_rpt?site_no=07381600

Superseded online Water-Data Reports3

UPT14 https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 640)

UPT14 https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 632)

UPT14 https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 690)

TAR https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 78)

TAR https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 81)

TAR https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 79)

ORO1 https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 380)

ORO1 https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 390)

ORO1 https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 432)

RDR https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 640)

Table 2. Publicly available online data sources for retrieving revised results and metadata, and publicly available online data sources 

that contain results superseded by this report.

[Stations are organized in order approximately upstream to downstream. Printable reports available through U.S. Geological Survey (USGS) online repositories 

have been watermarked to reflect the findings presented in this report. Data users that rely on local copies of printed reports should be aware that the suspendedsediment data in the Water-Data Reports for these stations are no longer considered reliable. Printed Water-Data Reports for samples before 2003 are not 

available online but are also deprecated by this report. NWIS, USGS National Water Information System database; QWDATA, a database within NWIS that 

contains results of discrete water-quality samples; USACE, U.S. Army Corps of Engineers; URL, uniform resource locator] 
Description of the Cooperative Program 7

Table 2. Publicly available online data sources for retrieving revised results and metadata, and publicly available online data sources 

that contain results superseded by this report.—Continued

[Stations are organized in order approximately upstream to downstream. Printable reports available through U.S. Geological Survey (USGS) online repositories 

have been watermarked to reflect the findings presented in this report. Data users that rely on local copies of printed reports should be aware that the suspendedsediment data in the Water-Data Reports for these stations are no longer considered reliable. Printed Water-Data Reports for samples before 2003 are not 

available online but are also deprecated by this report. NWIS, USGS National Water Information System database; QWDATA, a database within NWIS that 

contains results of discrete water-quality samples; USACE, U.S. Army Corps of Engineers; URL, uniform resource locator] 

Sampling location code1 URL

Superseded online Water-Data Reports3—Continued

RDR https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 632)

SIM https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 382)

SIM https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 392)

SIM https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 434)

WLO https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 396)

WLO https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 406)

WLO https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 449)

MCY https://pubs.usgs.gov/wdr/WDR-LA-03-1/pdf/wdrla03-1.pdf (p. 402)

MCY https://pubs.usgs.gov/wdr/2004/wdr-la-04-1/pdfs/WDR-LA-04-1.pdf (p. 411)

MCY https://pubs.usgs.gov/wdr/2005/wdr-la-05-1/pdfs/WDR_LA-05-1.pdf (p. 454)

1

These three-letter codes are a convention used only in this report. Corresponding locations and station codes for the sites are found in figure 1 and table 1.

2

Superseded Water-Year Summary Reports for inactive sites can be accessed at https://wdr.water.usgs.gov/allsearch.php by typing the desired station number 

in the search box. 

3

All suspended-sediment data for these stations in printed Water-Data Reports are superseded. Links shown here are for online Water-Data Reports only. 

4

The station number in use at the time the report was printed was for UPT1; the station number for UPT2 had not yet been created. The sampling location was 

UPT2 in 2003 through 2005 (fig. 1, table 1).

Description of the Cooperative Program 

The cooperative program includes collection of stream 

discharge measurements and collection and analysis of 

suspended-sediment and bed-sediment samples. This report 

addresses the data pertaining to instantaneous stream discharge 

and suspended-sediment samples, as well as daily suspendedsediment loads modeled from suspended-sediment and 

discharge data. The purpose of the program description below 

is to document practices that were in place prior to February 

2015. Samples collected and analyzed after February 2015 

have been processed with different methods than the methods 

described below. 

Cooperative Program History

The USACE MVN has been collecting sediment samples 

at selected sites (fig. 1, table 1) on the lower Mississippi and 

Atchafalaya Rivers since 1952 (Keown and others, 1977). By 

1963, the USACE MVN had established sediment sampling 

at five of the sites (table 1) that eventually became part of 

the cooperative program with the USGS in 1973. From 1963 

to 1973, the USACE MVN was exclusively responsible 

for sample collection, data analysis, and reporting of all 

information related to the project. During this period, the 

USACE MVN Testing and Materials Branch Sediment 

Laboratory in New Orleans, La., analyzed the sediment samples 

(Keown and others 1977, p. A24). 

In June 1973, the USACE MVN entered into a 

cooperative agreement with the USGS Louisiana Water 

Science Center. Through the cooperative agreement, the USGS 

Baton Rouge Sediment Laboratory at the Louisiana Water 

Science Center in Baton Rouge, La., assumed responsibility 

for laboratory analysis, following the protocol developed by 

the USACE. Additionally, in 1973, USGS field crews began 

field sampling at two sites on the lower Atchafalaya River 

(fig. 1, table 1). The USGS field crews followed the same field 

protocols and sampling design that the USACE had been using 

for the other sites. 

From 1973 through 1986, the USGS sent stream 

discharge measurements from the sites on the lower 

Atchafalaya River, as well as the raw data from laboratory 

analyses of all seven sites, to the USACE for processing. The 

USACE digitized the raw values and then used a FORTRAN 

program developed by the USACE MVN Hydraulics and 

Hydrologic Branch in 1974 (app. 1) to process the data. 

The USACE FORTRAN program used raw laboratory data, 

cross-sectional stream depth and velocity profiles, and daily 

stream discharge information to produce SSC, particle-size 

distribution, instantaneous suspended-sediment discharge, and 

daily suspended-sediment loads for a given water year. The 

USACE returned the results from their FORTRAN program 

to the USGS Louisiana Water Science Center for subsequent 

reporting by the USGS. The USGS stored the results for 

SSC, percent fines, instantaneous stream discharge, and 

instantaneous suspended-sediment discharge in QWDATA. 
8 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

In 1986, the USGS received a copy of the USACE 

FORTRAN program from the USACE and began using it 

to process data. The USGS supplied raw laboratory data, 

digitized input files, and output reports from the FORTRAN 

program to the USACE during this period. Eventually the 

USACE stopped separately digitizing the laboratory data and 

relied on digitized input files produced by the USGS, which 

USACE used to produce their own independent outputs. 

In 2007, the USACE discontinued their use of the 

USACE FORTRAN program. The USGS continued to use the 

USACE FORTRAN program and existing workflow without 

interruption to process and report sediment data. The USGS 

supplied output reports to the USACE but did not supply 

digitized input files or raw laboratory data. 

In October 2009, the USGS took over field sampling 

at two of the sites, one on the Old River Outflow Channel 

and one on the upper Atchafalaya River (table 1). The USGS 

continued using the established cooperative program field 

protocols at these two sites through the project period covered 

by this report. The USACE continued to collect discharge 

measurements and field samples at the two sites on the 

Mississippi River (table 1). Suspended-sediment sampling at 

Red River was discontinued in February 2005.

Site Locations

The seven sites (table 1) are located in the lower 

Mississippi River system in the vicinity of the Old River 

Outflow Channel and its confluence with the Red and 

Atchafalaya Rivers, as well as near the mouth of the 

Atchafalaya River (fig. 1). The discharge from the main stem 

Mississippi River into the Atchafalaya River is maintained 

by the USACE through the Old River Outflow Channel and 

the ORCC. The Old River Outflow Channel flows into the 

Red River, and the Atchafalaya River is the combined system 

below the confluence. The Atchafalaya River flows south and 

discharges into the Gulf of Mexico through two distributaries 

near Morgan City, La. (figs. 1 and 2). 

The sampling sites were selected to represent points 

upstream and downstream of major nodes in the hydrologic 

network around the ORCC (fig. 2). The Union Point/Coochie 

site (UPT) represents the stream discharge and suspendedsediment discharge of the Mississippi River upstream of the 

ORCC. The Tarbert Landing site (TAR) represents the stream 

discharge and suspended-sediment discharge on the main 

stem Mississippi River downstream of the ORCC. The Old 

River Outflow Channel site (ORO) represents the stream 

discharge and suspended-sediment discharge through the Old 

River Outflow Channel, which hydrologically connects the 

Mississippi and Atchafalaya Rivers. The Red River site (RDR) 

represents the stream discharge and suspended-sediment 

discharge in the Red River upstream of its confluence with 

the Old River Outflow Channel. The Simmesport site (SIM) 

represents the stream discharge and suspended-sediment 

discharge on the Atchafalaya River below the confluence of 

the Red River and the Old River Outflow Channel. The Wax 

Lake Outlet (WLO) and Morgan City (MCY) sites together 

represent the outflow of the Atchafalaya River that discharges 

into the lowermost delta and Gulf of Mexico. 

Within the context of the node-based sampling design, 

the sediment sampling and gaging locations at each site 

have not been consistent for the entire program history. For 

example, in 1991, the construction of the hydropower channel 

on the ORCC necessitated a change in the UPT sediment 

sampling location from its original location near the mouth of 

the new channel (UPT1) to a point 9 miles upstream (UPT2; 

fig. 1, table 1). The Old River Outflow Channel sampling 

location at ORO was moved from ORO1 approximately 

2 miles upstream (eastward) to ORO2 when the USGS took 

over field sampling from the USACE in October 2009 (fig. 1, 

table 1).

Sediment samples typically were collected within 

1 river mile of the points marked on the map (fig. 1) during 

the corresponding time periods noted in table 1. When field 

conditions made collection unsafe or impractical, sediment 

samples were collected at a secondary location within 2 river 

miles of the marked points at the discretion of the field 

crew. When the field crew sampled at a secondary location 

they selected its position to maintain representativeness of 

the sample within the hydrologic context of the node-based 

sampling design. 

Sampling Design

The sampling design for the USACE suspended-sediment 

program originally served four purposes. The goals were to 

• Produce a discharge-weighted average SSC suitable for 

use in computing instantaneous suspended-sediment 

discharge and suspended-sand discharge;

• Estimate daily and annual suspended-sediment load 

through the different nodes of the system; 

• Characterize the spatial distribution of SSC and particle 

size within the X-Y plane of the river cross section 

for subsequent parameterization of spatial models of 

sediment transport; and

• Characterize the particle-size distribution of the 

suspended sediment and the bed sediment. 

To accomplish these goals, a multivertical point-sampling 

design was used to collect the samples. The verticals were 

collected at fixed horizontal positions across the stream cross 

section. At each vertical, point samples were collected at 

defined fractions of the total depth below the water surface. 

This allowed each point sample to be related to an X-Y 

position within the cross section. The horizontal position of 

the verticals in the cross section, the number of point samples 

in each vertical, and the target fraction of the total depth 

for each point sample were assigned by USACE program 

managers. In general, during the period covered by this report, 

point samples were collected at 4 or 5 depths at 3 or 4 verticals 
Description of the Cooperative Program 9

for a total of 12–20 point samples for each cross-sectional 

sample. The number of verticals and target depths, and hence 

the number of point samples collected in each sampling event, 

changed over the history of the cooperative program and 

varied among the different sites. 

The USACE program managers also set the number of 

samples collected in each water year, which varied by site 

over time. During the late 1970s and early 1980s, sampling 

occurred biweekly at most sites and more frequently at 

some sites. Later, samples were collected less frequently as 

resources were shifted away from sediment programs. By 

the middle of the period covered in this report, 12–18 crosssectional samples were collected each water year at most sites, 

normally on a monthly basis for lower flow periods and on a 

biweekly basis during higher flow periods of the year. 

Field Methods

Field crews measured instantaneous stream discharge 

at the cross sections where sediment samples were collected. 

Stream discharge measurements were made near the time of 

sampling, usually before sediment sampling so that the correct 

depths for the point samples could be determined. Discharge 

was measured with either a “conventional” Price AA current 

meter (Buchanan and Somers, 1969) or an acoustic Doppler 

current profiler (ADCP) (Mueller and Wagner, 2009). 

Suspended-sediment samples for the cooperative program 

were collected with a P-61, P-63, or P-6-200 point sampler 

with a 3/16-inch nozzle suspended from a boat. These point 

samplers are designed to collect isokinetic samples when 

operated in the approved range of stream depths and water 

velocities (Davis, 2005). Isokinetic sampling ensures that the 

velocity of the flow into the sampler is equal, or nearly equal, 

to the stream velocity near the sampler nozzle; this condition 

must be met for representative sampling of suspended 

sediment (Edwards and Glysson, 1999, p. 15). 

The P-61 and P-63 samplers can be used with either 

pint- or quart-sized bottles (Davis, 2005). Until March 2014, 

USGS crews used pint bottles, and USACE crews used quart 

bottles. The USGS began using the P-6-200 sampler (Federal 

Interagency Sedimentation Project, 2011) with quart bottles in 

March 2014. 

Changes were made to the collection techniques over 

time. For example, an unpublished standard operating 

procedure from the USACE documented a switch from plastic 

to brass 3/16-inch nozzles for the point samplers. Similarly, in 

2004, the USACE crews began including a nozzle rinse step 

between verticals to prevent cross contamination between the 

bottom sample bottle of one vertical and the top sample bottle 

of the next vertical. 

During sample collection, the crew located the assigned 

vertical in the cross section by moving a fixed distance from 

a reference point on the bank or by moving to a set of Global 

Positioning System (GPS) coordinates that represented 

the correct position. The total depth at each vertical was 

determined by sounding weight, bed sampler, bottom sounder, 

fathometer, or ADCP. The sampler was lowered to the water 

surface, and the depth indicator was reset to zero. The sampler 

was then lowered to the target fraction of the depth specified 

in the cooperative program sampling plan. The sampler 

valve was opened, and the water sample was collected. The 

sampling duration was selected on the basis of the observed 

water velocity and nozzle size. The goal when setting the 

sampling duration was to allow the bottle to collect sufficient 

water without overfilling, although changes in field conditions 

during sampling sometimes resulted in some point samples 

not meeting the target volume. The valve was closed, and the 

sampler was lifted to deliver the sample to the operator. The 

boat operator held the boat as motionless as possible relative 

to banks and waypoints throughout the sampling process at 

each vertical. 

The P-61, P-63, and P-6-200 samplers are expected to 

collect isokinetic samples when stream velocity is greater than 

1.5 feet per second and less than 10 feet per second (P-61, 

P-6-200) or 15 feet per second (P-63) (Davis, 2005; Federal 

Interagency Sedimentation Project, 2011). When average 

stream velocities fell below 1.5 feet per second, USGS crews 

sometimes used a Van Dorn sampler (Wildco) to collect 

non-isokinetic samples. The Van Dorn sampler was manually 

lowered to the target fraction of the depth in the vertical and 

the messenger weight sent down the rope to close the sampler. 

The operator then pulled the sampler back up and transferred 

the water sample to the sample container as quickly as 

possible to not allow for settling. Water was poured swiftly 

and freely into a sample bottle without allowing the water to 

overfill, slosh, or spill from the bottle. Excess water in the 

Van Dorn sampler that did not fit into the bottle was discarded.

When stream velocities were too low to adequately 

fill the sample bottles by using standard procedures, field 

modifications such as towing the sampler through the water 

or sampling with the nozzle removed were sometimes used 

to collect non-isokinetic samples. At velocities less than 

1.5 feet per second it was unlikely that any sand would be in 

suspension, and thus the effect of non-isokinetic sampling 

conditions would be negligible. 

Field crews were not always able to use a uniform 

sampling duration for every bottle in a cross section. A 

sampling duration short enough to prevent overfilling the 

bottles in high-velocity areas of the cross section sometimes 

resulted in very small sample volumes in low-velocity areas 

of the cross section. At some points in the program history, 

some field crews responded to this situation by increasing 

the sampling duration for bottles in low-velocity zones of the 

stream cross section. 

Following collection, water samples were stored in a 

cool, dark environment to prevent biological growth in the 

containers. Bottles were labeled with the appropriate field 

metadata and transferred to the USGS Baton Rouge Sediment 

Laboratory for analysis.
10 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Laboratory Analysis Methods

The cooperative program laboratory protocol was 

developed by the USACE MVN Testing and Materials Branch 

Sediment Laboratory, New Orleans, La. The first known 

published description of the technique is in Keown and others 

(1977, p. A23). The cooperative program laboratory protocol 

was exclusively used on samples collected for the cooperative 

program; sample results for other programs that used the 

USGS Baton Rouge Sediment Laboratory were produced with 

other approved USGS methods, chiefly those described by 

Guy (1969). 

Each point-sample bottle and the river water it contained 

were weighed to the nearest 0.1 gram. The sediment was 

allowed to settle until the overlying river water was clear. 

The settling period was usually a minimum of 2 weeks. The 

overlying river water was decanted from the settled sediment 

(fig. 3). Decanting is used to concentrate the sediment in 

a sample into a manageable volume (Guy, 1969), which 

improves handling during subsequent analysis. The river water 

was decanted with a vacuum line attached to a short length 

of copper pipe. The copper pipe had an inlet hole drilled 

90 degrees to the main axis of the pipe near the end. The pipe 

was lowered slowly into each point-sample bottle to remove 

the overlying river water through the inlet hole, which allowed 

the analyst to remove most of the overlying water through the 

vacuum line without disturbing the sediment below the inlet 

hole. The overlying river water contained dissolved solids. 

The concentration of dissolved solids in the river water and the 

volume of the residual overlying river water remaining in each 

point-sample bottle were not measured during this step.

The sediment and residual overlying river water in each 

bottle were washed through a 3-inch-diameter 0.063-mm sieve 

(US 230 sieve) with deionized (DI) water to separate the sand 

from the fines (fig. 3). The material retained on the sieve was 

rinsed into a tared 100-milliliter beaker, allowed to settle for 

3–5 seconds, decanted with the vacuum system, oven dried 

at 103±2 degrees Celsius (°C), cooled in a desiccator, and 

weighed to the nearest 0.0001 gram. Separating the sand in 

this way was comparable to a wet sieve “sand break” analysis, 

which separates suspended-sediment samples into sand and 

fines to allow the reporting of the percent fines along with 

SSC. 

The dry sand in the beaker was transferred to a stack 

of 3-inch-diameter sieves (1.0-mm, 0.500-mm, 0.250-mm, 

0.0125-mm, and 0.063-mm openings) and shaken for 1 minute 

on a small automatic sieve shaker (fig. 3). The cumulative 

weight retained on each sieve was recorded to the nearest 

0.0001 gram to determine the particle-size distribution of the 

sand for each point-sample bottle. The cumulative weight 

retained on the 0.063-mm sieve during the dry sieve analysis 

could be compared to the sand mass from the wet sieve 

analysis; under ideal conditions the two values would be 

equal.

The 3-inch-diameter 0.063-mm sieve used for the wet 

sieve analysis was supported by a holder on top of a modified 

riffle splitter (figs. 3 and 4) that split the suspension passing 

the sieve into two separate portions. After the wet sieve 

step, the sieve and both sides of the splitter were thoroughly 

rinsed with DI water. The rinsate collected on one side of the 

splitter was used to determine the percent fines for the point 

sample. The rinsate from that side was captured in a tared 

100-milliliter beaker, oven dried, and weighed to the nearest 

0.0001 gram to determine the “half-fines” mass of fines for 

each bottle. The sand mass and the doubled “half-fines” mass 

were used to determine the SSC and percent fines for each 

bottle (app. 1). 

The rinsate collected from the other side of the splitter 

was physically composited among all of the point-sample 

bottles in the cross-sectional sample and used to determine the 

composite particle-size distribution of fines. This portion of 

the rinsate was collected in a larger beaker that was tared to 

the nearest 0.1 gram. The composite subsample was typically 

collected off the left side of the splitter; that is, on the side of 

the splitter to the left of the analyst. 

The composite subsample was allowed to settle until 

the overlying water was clear, usually for at least 2 weeks. 

A 50-milliliter aliquot of the supernatant was withdrawn 

with a pipette and transferred to a tared 100-milliliter beaker, 

oven dried, cooled in a desiccator, and weighed to the nearest 

0.0001 gram (fig. 3). The composite subsample was then 

decanted with the vacuum system. The residual volume of the 

composite subsample after decanting was recorded as the net 

weight of the large beaker, rounded to the nearest gram, using 

an assumed density of 1 gram per milliliter for the sediment/

water suspension in the beaker. The aliquot mass and the 

residual volume could be used to compute a dissolved-solids 

correction for the bottom-withdrawal (BW) tube analysis. 

The dissolved-solids concentration for the BW tube analysis 

was not equivalent to the environmental dissolved-solids 

concentration in the river water because the suspension in the 

beaker used for the composite subsample contained the DI 

water used to rinse the splitter. 

The remaining suspension was transferred to a blender, 

where it was mechanically dispersed, and then rinsed into a 

BW tube. The BW tube, which is similar to a 500-milliliter 

burette, was filled to the 100-centimeter line with DI water. 

A BW tube analysis was conducted on the composite fines 

(fig. 3). The BW tube analysis generally followed the method 

described by Guy (1969), which was originally developed 

by the U.S. Subcommittee on Sedimentation, Inter-agency 

Committee on Water Resources (1943). In contrast to the 

specification in Guy (1969), no chemical dispersant was 

included in the BW tube suspension.

To start the BW tube analysis, the tube was inverted 

several times over a period of 5 minutes to fully mix the 

suspension in the tube. After 5 minutes, the tube was secured 

upright, and a stopwatch was started to time the analysis. At 

predetermined times of 4, 8, 13.5, 25, 50, 66, 88, 100, and 

120 minutes after the beginning of the analysis, 10 centimeters 

of the overlying suspension was released through the valve at 

the bottom of the tube and collected into a tared 100-milliliter 
Dry sieve

Individual

sands

Oven dry

Split

Individual

half fines

Composite

half fines

15–20 point-sample

bottles

Settle Decant

W

(

was

Oven dry

EXPLANATION

Dissolved solidsDeionized waterFinesSand

US 230US 120

US 60US 35US 18

US 230

Figure 3. The laboratory method, including the wet sieve/split, “half fines,” dry sieve, and bottom-withdrawal (BW) tube analysis steps, used in the cUS 230 sieve has a 0.063-millimeter (mm) opening, the US 120 sieve has a 0.125-mm opening, the US 60 sieve has a 0.250-mm opening, the US 35 sieve and the US 18 sieve has a 1.0-mm opening. The term “fines” is used for sediment that passes a 0.063-mm sieve; the term “sand” is used for sediment tmm sieve (illustration by L.S. Coplin, U.S. Geological Survey).
12 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Figure 4. U.S. Geological Survey laboratory technician at the 

Baton Rouge Sediment Laboratory processing a water sample 

with the modified riffle splitter used to analyze cooperative 

program samples (photograph by Aimee Downs, U.S. Geological 

Survey).

beaker. A 10th beaker containing the final 10 centimeters of 

suspension was collected immediately after the 120-minute 

withdrawal. After the timed withdrawals, no suspension 

remained in the BW tube. The walls of the BW tube were 

rinsed with DI water into a tared 100-milliliter beaker. All of 

the beakers were oven dried at 103±2 °C and then cooled in 

a desiccator, and their weights were recorded to the nearest 

0.0001 gram. 

Before the BW tube analysis started, the temperature of 

the suspension was recorded. Two more temperature readings 

were taken in the middle and near the end of the settling 

period. The final recorded temperature was the average of the 

three temperature readings. 

The withdrawal weights, average water temperature, and 

settling times from a BW tube analysis can be used to compute 

particle-size distribution based on fall diameter on the basis of 

a graphical interpolation of the Oden curve (Guy, 1969; U.S. 

Subcommittee on Sedimentation, Inter-agency Committee 

on Water Resources, 1943). For the cooperative program, 

the USACE FORTRAN code computationally simulated a 

graphical interpolation of the Oden curve (app. 1). 

The outcome of the BW tube analysis was a composite 

particle-size distribution for the fines in the cross section. The 

composite percent fines in the cross section was computed 

from the sand analysis, the “half fines” analysis, and the 

BW tube analysis and was used to scale the fine particle-size 

results from the BW tube to the sand analysis results for final 

reporting (app. 1). 

The goal of the laboratory protocol for cooperative 

program samples was to provide SSC and particle-size 

distribution for every point-sample bottle in a cross section, 

as well as aggregated cross-sectional particle-size and SSC 

data. The technique was a compromise between the physical 

limitations of the laboratory methods used for determination 

of particle-size distribution of the fines and the goal of 

understanding the spatial distribution of suspended sediment 

by size within the cross section. Sediment in the fine-particle 

size range tends to be more homogenous in the stream cross 

section than are sand-sized particles (Edwards and Glysson, 

1999, p. 2).

Data Flow and Information Systems Methods

The data generated by the laboratory analysis were 

recorded on a laboratory data sheet (app. 2) and subsequently 

entered into the USACE FORTRAN program (app. 1). The 

original USACE FORTRAN program required that data be 

prepared in an 80-column “card” format. Subsequent revisions 

to the software allowed the USACE FORTRAN code to read 

digital text files as inputs but did not change the structure 

of the input data. The information on the laboratory data 

sheet was transcribed by either the USACE or USGS into 

an 80-column text file (SED file, app. 3) for input into the 

software. 

Prior to 2001, the source of the inputs to the USACE 

FORTRAN program was a handwritten laboratory form that 

was filled out by laboratory personnel as they completed 

different steps of the analysis (app. 2). After 2001, the source 

of the inputs to the USACE FORTRAN program was a printed 

Excel-format laboratory form that was used by the laboratory 

to automate some of the computations. The Excel spreadsheet 

was designed to replicate the paper laboratory form.

The laboratory form contained some information from 

the field forms that were submitted to the laboratory along 

with the point-sample bottles. Various field forms were 

used over time, but they all included the station code and 

name, date, time, and stream discharge at the time of sample 

collection, along with the cross-sectional location of each 

point-sample bottle and the total depth of the river at each 

vertical. Laboratory personnel transcribed the required 

information from the field form to the laboratory form. 

The laboratory form included information that was not 

included in the 80-column text file (SED file). Specifically, 

the text file did not contain information on the dish type, dish 

number, gross weight, and tare weight of the dishes used in 

the analysis. The USACE FORTRAN program operated on 

only net weights. Prior to 2001, net weights for dishes were 

computed by hand or with a calculator. Since 2001, net weight 

computations have been performed in the Excel spreadsheet. 

The laboratory form also contained annotations about quality 

issues that may have been observed during the laboratory 

process, such as broken bottles, broken dishes, or visible glass 

particles that may have been present in the sample.

The laboratory form did not include fields for the 

gross weight and tare weight of the point-sample bottles. 

Information in this field was calculated manually, and the 

net weight was entered directly onto the laboratory form. 
Description of the Cooperative Program 13

Bottle tare weights were inscribed on each bottle as is standard 

practice for sediment sampling programs. Bottle gross weights 

were measured in the laboratory for each sample to the nearest 

0.1 gram.

The first page of the laboratory form held information 

for 15 point-sample bottles, along with the values produced 

during the BW tube analysis. When more than 15 pointsample bottles were collected for a cross-sectional sample, 

multiple pages, or multiple Excel files, were used to hold the 

information about the additional point-sample bottles.

When sufficient data were submitted by the field crew, 

the data technicians prepared SED files and other text files that 

contained cross-sectional depth and velocity profiles for the 

sampling events (DIS files). The DIS file for some discharge 

measurements included data for the horizontal position, total 

depth, and velocity at the 0.6 fraction of the depth for many 

verticals in the cross section. When the field crew did not 

submit sufficient data, the DIS file did not contain crosssectional depth and velocity profiles. In such cases, the DIS 

file simply contained lists of sampling dates and the measured 

stream discharge for each sampling event. 

A SED file and a DIS file were prepared for each water 

year (October 1 through September 30) at each site. The 

laboratory data for the first and last cross-sectional sample for 

each water year were duplicated so that the data for the first 

cross-sectional sample in one SED file were the same as the 

data for the last sample from the previous year. 

The USACE FORTRAN program was used to produce 

the output files, which included a human-readable threepage report (3PG file), a water year summary of SSC and 

suspended-sediment discharge for each sampling event (SUM 

file), and a machine-readable file that was subsequently used 

by a different USACE FORTRAN module for computing 

daily loads (HES file). A third USACE FORTRAN module 

transformed the HES file into a different machine-readable 

format (SS1 file). A fourth USACE FORTRAN module 

(app. 1) paired the SS1 file with a list of daily discharge 

readings (DSS file) to estimate daily loads (DLD file).

The USGS data technicians submitted the output 

files and the laboratory forms to the leader of the local 

data management group or other science lead at the USGS 

Louisiana Water Science Center for review. The reviewer 

sometimes determined that specific bottles appeared to have 

been “busted”; that is, sampled too close to the river bottom. 

The data technicians would delete the rows for the rejected 

bottles from the SED files and rerun the software to produce 

updated results. 

Computations

Details of the computations used for particle-size 

distributions and other results were inferred from the USACE 

FORTRAN code (app. 1). The description of the computations 

in this section serves to document past practices only. Some of 

the methods described below are not traced to citable method 

references. Documentation here does not imply that the 

methods represent USGS-approved techniques.

SSCs were computed in parts per million by mass, in 

units of milligrams per kilogram. At concentrations below 

16,000 milligrams per kilogram, SSC in milligrams per 

kilogram is equivalent to SSC in milligrams per liter when 

rounded, assuming a standard sediment density of 2.65 grams 

per cubic centimeter and a standard water density of 1.00 gram 

per cubic centimeter (Guy, 1969); all environmental values 

for the entire dataset were well below this threshold. Symbols 

for the input values, along with their corresponding variable 

names and physical interpretation, are presented in table 3. 

The concentrations of sand, fines, and suspended 

sediment were computed for each bottle by

mg sand mL "water" 1,000 1,000

g sand L "water"

ds

S

b

m C

V    , (1)

2 mg sediment mL "water" 1,000 1,000

g sediment L "water"

ws hf

t

b

m m C

V

    , and (2)

C C f t  CS

, (3)

where

CS was the suspended-sand concentration, in 

milligrams per liter or parts per million, 

in each bottle; the USACE FORTRAN 

program called this fraction the “retained” 

fraction because it was retained on a 

0.063-mm sieve; 

mds was the cumulative mass of sand measured on 

the 0.063-mm sieve in the dry sieve sand 

analysis (table 3), in grams;

Vb was the volume of sediment/water suspension 

(“water”) in the bottle, in milliliters, 

converted from the bottle net weight by 

assuming the river water had a density of 

1 gram per cubic centimeter (table 3);

Ct was the SSC, in milligrams per liter or parts 

per million, in each bottle;

mws was the mass of sand retained on the 

0.063-mm sieve during the wet sieve/split 

procedure (table 3), in grams;

mh f was the mass of fines in the “half fines” 

beaker (table 3), in grams; and

Cf was the suspended-fines concentration, in 

milligrams per liter or parts per million, 

in each bottle; the USACE FORTRAN 

program called this fraction the “passing” 

fraction because it passed a 0.063-mm 

sieve.
Table 3. Fields used in the laboratory data sheet transcribed by either the U.S. Army Corps of Engineers (USACE) or the U.S. Geological Survey (USGfile (SED file, app. 3) for input into the USACE FORTRAN software (app. 1) or to evaluate and compute the corrected results for samples collected betwFebruary 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. [Only fields that were used to compute the revised results were fully verified during the program review. Other fields that did not affect the reported results, such as the bottom-waverage water temperature, are available from laboratory data but not cataloged here. “Fines” refers to sediment that passes through a 0.063-millimeter (mm) sieve (US 230 siev

Scale Symbol Variable name Description Unit Precision Source Individual bottle Vb TVOL Bottle volume Milliliter1 1 Volume of sediment/water suspension in the bottle bef

mws SANDW Wet sieved sand Gram 0.0001 Mass of sand retained on the 0.063-mm sieve that cove

during the wet sieve/split procedure. mds US230 Dry sieved sand Gram 0.0001 Cumulative mass of sand retained on the 0.063-mm sieanalysis of the sand fraction. mhf HFINE “Half fines” Gram 0.0001 Mass of material from the subsample of the fines that wtube analysis. This dish contained residual dissolved 

DISTRP DISTRP Distance from reference point Foot 1 Horizontal position of the vertical within the stream crDESTA DESTA Depth at station Foot 1 The total depth of the vertical. DESAM DESAM Depth of sample Foot 0.1 Depth below the water surface of the point from which 

Composite subsample VBW BWVOL BW volume Milliliter1 1 Residual supernatant volume remaining after decanting 

mdsol BWDS BW dissolved solids Gram 0.0001 Mass of material in 50 milliliters of supernatant from t

after settling. mBW BWW BW weights (10) Gram 0.0001 Mass of material in each of 10 withdrawals made durin

mwc BWWC BW wash correction Gram 0.0001 Mass of material rinsed out of the BW tube after the fi

1Volumes are measured by mass to the nearest 0.1 gram, assuming a density of 1 gram per milliliter, and then rounded before recording on the laboratory data sheet or transcri
Description of the Cooperative Program 15

When cross-sectional depth and velocity profiles were 

not entered in the DIS file, the cross-sectional suspended-fines 

concentration and SSC for the sample were computed as a 

numerical average:

1  

n

i f i

f

C

C

n

 

 , and (4)

1 ( )

n

i t C i C

n

   , (5)

where

Cf was the numerical average suspended-fines 

concentration, in milligrams per liter or 

parts per million; 

n was the number of bottles in the crosssectional sample; and

C was the numerical average SSC, reported 

as the cross-sectional SSC (p80154), in 

milligrams per liter or parts per million.

The suspended-sediment discharge was computed as the 

product of the stream discharge and the cross-sectional SSC, 

with a standard unit conversion:

3

s L short tons 0.0027

day ft mg

Q C S Q      

(6)

where

QS was the instantaneous suspended-sediment 

discharge for the sample (p80155), in short 

tons per day;

Q was the instantaneous stream discharge 

(p00061) recorded on the SED file, in 

cubic feet per second; and

0.0027 was a factor used to convert the units: 

86,400 seconds/day × 28.32 L/ft3 × 1.102 × 

10-9 short tons/mg.

When cross-sectional depth and velocity profiles were 

entered in the DIS file, the cross-sectional SSC for the sample 

was computed as a discharge-weighted average by using the 

velocity-area method (app. 1). First, a grid was constructed 

through the points halfway between each sediment vertical 

and halfway between each sediment point depth. The grid 

was extended to the edge of the cross section on the left and 

right, and the cross-sectional area in each resulting cell, α, was 

calculated. The horizontal location, stream depth, and water 

velocity at the 0.6 fraction of the depth was used to estimate 

the velocity at 1-foot depth increments for each velocity 

vertical. Many more verticals were measured for depth and 

velocity than were used to collect point suspended-sediment 

samples. The velocity at each 1-foot depth increment was 

estimated with an unreferenced power law equation that 

depended on the water temperature: 

0.1198 0.00048  1.8 32 v C z   T   , and (7)

0.6   1

v

h d v

z h

v v z d

        , (8)

where

zv was a temperature-dependent factor that 

defined the power law equation; 

TC was the water temperature, in degrees Celsius; 

vh was the velocity at a point located a distance h 

above the channel bed in the water column, 

in feet per second; 

v0.6d was the velocity at the 0.6 fraction of the total 

depth at the vertical from the input file, in 

feet per second; 

h was the distance from the channel bed to the 

point for which the velocity was being 

determined, in feet; and

d was the total depth of the stream at the 

vertical where the velocity was measured, 

in feet.

The initial average velocity for the sediment grid cell, v , was 

computed as the numerical average of all of the estimated 

velocity points (eq. 8) that fell within the cell or on the edge of 

the cell boundary.
16 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

The initial average velocities were used to create an 

initial estimate of the stream discharge, Qi, through each 

sediment grid cell:

Q v i  a, (9)

where

Qi was the initial estimate of the stream 

discharge in a sediment grid cell, in cubic 

feet per second; 

v was initial average velocity for a sediment 

grid cell, in feet per second; and

a was the computed cross-sectional area of a 

sediment grid cell, in square feet.

The stream discharges for each of the sediment grid cells 

were summed to estimate the instantaneous stream discharge. 

The instantaneous stream discharge estimated by this method 

was compared to the instantaneous stream discharge recorded 

in the SED file. The stream discharge in each grid cell was 

adjusted to ensure that the instantaneous stream discharge 

recorded in the SED file and the sum of the sediment-grid-cell 

stream discharges were similar: 

( 1)  

n Q Q ba i i i   , (10)

Q

ba

Q f Q , (11)

Q f a Q  va, and (12)

1  

n Q Q t i a i   , (13)

where

Qba was the estimated total stream discharge from 

the sediment grid cells, in cubic feet per 

second; 

f

Q was a correction factor for adjusting the grid 

cell discharges; 

Qa was the adjusted stream discharge in each 

sediment-sampling grid cell, in cubic feet 

per second; and

Qt was the stream discharge estimated by 

applying the velocity-area method to each 

sediment-sampling grid cell, in cubic feet 

per second. 

The sediment discharge for each sediment grid cell was 

computed by multiplying the stream discharge computed for 

the sediment grid cell, Qα, by the SSC recorded for the point 

at the center of the cell, with a standard unit conversion factor 

(eq. 6). The discharge-weighted average suspended-fines 

concentration and SSC were then determined as the total 

suspended-fines concentration and SSC divided by the total 

stream discharge:

3

s L short tons 0.0027

day ft mg

Q Q f aCf

      

, (14)

3

s L short tons 0.0027

day ft mg

Q Q sc a t C       

, (15)

1  

3

s L short tons 0.0027

day ft mg

n

i f i

f D

t

Q

C

Q

 

      

, and (16)

1  

3

s L short tons 0.0027

day ft mg

n

i sc i

D

t

Q

C

Q

 

      

, (17)

where

Qf was the instantaneous suspended-fines 

discharge in a sediment grid cell, in short 

tons per day; 

Qsc was the instantaneous suspended-sediment 

discharge in a sediment grid cell, in short 

tons per day; 

Cf D was the discharge-weighted suspended-fines 

concentration, in milligrams per kilogram 

or milligrams per liter; and

CD was the discharge-weighted SSC, reported 

as the cross-sectional SSC (p80154), in 

milligrams per kilogram or milligrams per 

liter. 

The instantaneous suspended-sediment discharge was the 

sum of the suspended-sediment discharge computed for each 

sediment-sampling grid cell:

1  

n Q Q s i sc i   , (18)

where all variables are as described above.
Critical Review of Field, Laboratory, and Computational Protocols 17

For either method of producing the cross-sectional SSC, 

the USGS data technicians computed the percent fines by 

dividing the suspended-fines concentration by the SSC:

0.063 100 percent

Cf pf C   , or (19)

0.063 100 percent f D

D

C

pf C   , (20)

where

0.063 pf was the percent fines (parameter code 

p70331). 

The value for pf0.063 used by the USGS was not directly 

reported on any output from the USACE FORTRAN program. 

Rather, the 3PG output file reported the numerical average or 

discharge-weighted average pf0.063. The USACE FORTRAN 

algorithm did not use the reported pf0.063 for scaling the 

results of the BW tube analysis to the sand analysis. Instead 

the algorithm computed a composite scaling factor that was 

similar to the composite:

 1

10

1 1 1

1

50

n

i ds

n n BW

i ws i hf i BW wc dsol

m k

V m m m m m



  

               

, (21)

where

k was a factor that was used to scale the 

fines particle-size distribution to the 

sand particle-size distribution, and other 

symbols were as described in table 3.

Neither the scaling factor nor the average pf0.063 from the 3PG 

file was reported in USGS data dissemination applications. 

The suspended-sediment discharge and instantaneous 

stream discharge pairs for each sampling event in a water year 

were used to construct a model for predicting daily suspendedsediment discharge. A linear regression was computed 

between the base-10 logarithm of the suspended-sediment 

discharge and the base-10 logarithm of the instantaneous 

stream discharge (app. 1). A record of stream discharge for 

each day in the water year was assembled from an appropriate 

gage. The stream discharges were used to predict the daily 

suspended-sediment discharges with the regression equation. 

The predicted daily suspended-sediment discharges from 

the regression equation were then adjusted mathematically 

to ensure that the final reported values agreed with the 

measured SSC and stream discharge value pairs (app. 1). The 

adjustments took into account the temporal relation among the 

measured SSC and stream discharge value pairs. The USACE 

FORTRAN program used this method to compute daily 

suspended-sediment loads for each water year (DLD file). 

The daily loads were summed to produce annual suspendedsediment loads. 

Reporting

When a final output was approved for a water year, 

the USGS data technicians used the output from the SUM 

file to transcribe the sample results into QWDATA. The 

SUM file contained only the cross-sectional SSC, discharge, 

and suspended-sediment discharge data; data about SSC or 

particle-size distribution in individual point-sample bottles 

were not reported to QWDATA. The cross-sectional aggregate 

particle-size distribution for sizes other than 0.063 mm 

was similarly not reported to QWDATA. Data technicians 

transcribed the SSC (p80154), percent fines (p70331), 

instantaneous stream discharge (p00061), and instantaneous 

suspended-sediment discharge (p80155) results into 

QWDATA. When discharge weighting was used to compute 

the SSC for a sampling event, the 3PG file reported both the 

discharge-weighted and the numerical average SSC. The 

SUM file used the discharge-weighted average SSC when it 

was available and the numerical average when no discharge 

weighting was used. The p70331 value did not appear 

directly on the SUM file, so the data technicians computed it 

manually during the transcription process (eq. 19, eq. 20). The 

DLD and SUM files were used to prepare part of the WaterData Reports for USGS surface-water stations. The USACE 

did not publicly serve results produced by the cooperative 

program. 

Critical Review of Field, Laboratory, 

and Computational Protocols

In 2015, the USGS and USACE jointly initiated a 

comprehensive review of the cooperative program. The review 

was conducted by USGS personnel with active participation 

and support from the USACE. The review team compared 

cooperative program methods to current USGS policies 

and practices. After the review team determined that the 

laboratory methods used by the cooperative program caused 

systematic positive bias in SSC, a second purpose emerged 

of making recommendations for how to treat the previously 

published results. For SSC, percent fines, instantaneous stream 

discharge, and instantaneous suspended-sediment discharge, 

the review team determined that it was possible to provide 

revised results with methods that could be supported by 

current practices. The review documented recommendations 

for computing and reporting the revised results for these 

parameters. For particle-size distribution and daily/annual 

suspended-sediment loads, the review team determined that 

revised values could not be provided with current methods. 

The details and justifications for these conclusions are 

described in the following sections. 
18 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sampling Design Review

The review team evaluated the sampling design relative 

to the goals of computing a discharge-weighted average SSC, 

suspended-sediment discharge, and daily/annual loads at the 

measured locations. In brief, the team found that while the 

original sampling design could produce discharge-weighted 

average SSC, changes to the program over time had resulted in 

a loss of the capacity to compute this value correctly. The team 

further found that the suspended-sediment samples were not 

collected frequently enough to enable the reliable computation 

of suspended-sediment loads for a daily time step; the 

computation of loads on a seasonal or annual basis may be 

defensible. Further details and explanations of both findings 

are described below.

Discharge-Weighted Average SSC

Issues: The computations used by the cooperative 

program to mathematically discharge-weight the point-sample 

bottle SSC could not be evaluated relative to current USGS 

techniques because standard USGS methods for sedimentsample collection produce physically discharge-weighted 

samples (Edwards and Glysson, 1999). Consequently, the 

quality of the mathematically discharge-weighted average SSC 

could not be effectively evaluated during the review, nor could 

the review team recommend that the technique be adopted 

when computing the revised results.

The representativeness of the fixed point-sample 

locations within the cross section was unknown and varied 

among sites and over the program history. The fixed verticals 

were not located at centroids of equal-discharge increments 

of the stream (EDI method, Edwards and Glysson, 1999), nor 

were there normally enough verticals to meet the requirements 

of the EWI method (Edwards and Glysson, 1999). 

The number of point samples collected at each sampling 

event changed over the course of the program and varied 

among the sites. The review team expected that greater 

accuracy and precision were achieved when more point 

samples were collected. Some sampling events did not include 

bottles collected above the 0.5 fraction of the depth at any 

vertical. Underrepresentation of the upper portion of the 

vertical could lead to a high bias in the cross-sectional SSC 

because high SSC typically occurs deeper in the vertical. 

Previously reported SSC for the cooperative program 

contained a mix of discharge-weighted average and 

numerical average values. After the ADCP was fully 

adopted, the reported SSC was no longer discharge-weighted 

mathematically because the USACE FORTRAN program 

was not updated to use the ADCP data. Prior to the adoption 

of the ADCP, any time the field crew did not submit depth 

and velocity profiles from the discharge measurements, the 

SSC was not discharge-weighted mathematically. The review 

team hypothesized that the numerical average SSC would be 

biased high relative to the discharge-weighted average SSC 

because higher SSC typically occurs at points collected deeper 

in the vertical, where stream velocity and stream discharge 

are typically lower. The higher SSC in the lower part of the 

vertical was expected to be caused by spatial differences in 

the suspended-sand concentration through the cross section; 

spatial differences in suspended-fines concentration were 

expected to be small. 

Recommended Actions for Revising Results: The review 

team recommended that a single method of computing the 

SSC and percent fines for each sampling event should be 

used to eliminate the mixture of discharge-weighted averages 

and numerical averages that had been previously reported. 

The team further recommended that a comparison be made 

between the discharge-weighted average SSC and the 

numerical average SSC when both had been reported by the 

USACE FORTRAN program. The purpose of the comparison 

was to determine if the hypothesized bias could be verified 

and potentially quantified. 

Further, the team recommended that the number of 

points collected for each sampling event (p00063) should be 

reported along with the revised results in the publicly available 

data repositories (table 2) to allow data users to account for 

variable sampling effort among different sampling events. The 

review team further recommended that samples with no points 

collected in the upper half of any vertical should be reported in 

publicly available data repositories (table 2) with annotations 

to reflect the lack of representation of the upper part of the 

verticals. 

Outcomes: The revised results were reported to publicly 

available data repositories (table 2) with the recommended 

annotations. The effect of the aggregation method for SSC was 

analyzed in more detail. Output files (3PG) were recovered 

from both the USGS and USACE servers, and the dischargeweighted average SSC and numerical average SSC were 

extracted when both values were reported. Comparisons 

between discharge-weighted average and numerical average 

results were available for 913 pairs of events that occurred 

in the study period. Slopes of a linear regression model 

between the numerical average SSC and discharge-weighted 

average SSC showed that the discharge-weighted average 

SSC was 89–98 percent of the numerical average SSC for the 

cooperative program (table 4). Thus, numerical average SSC 

could be biased high by 2–11 percent relative to dischargeweighted average SSC, supporting the review team’s 

hypothesis. 

Daily Suspended-Sediment Load

Issues: The method used by the cooperative program to 

compute daily and annual suspended-sediment loads did not 

conform to current USGS standard policies and practices. 

First, the frequency of suspended-sediment data collection 

did not support the computation of daily suspended-sediment 

loads with an acceptable level of representativeness when 

using currently available models (for example, the USGS 

Graphical Constituent Loading and Analysis System [GCLAS; 

Koltun and others, 2006]) because the daily time step was 
Critical Review of Field, Laboratory, and Computational Protocols 19

Table 4. Comparison between discharge-weighted average and numerical average suspended-sand concentration, suspended-fines 

concentration, and suspended-sediment concentration for 913 events for which data were available for samples collected between 

October 1989 and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[The discharge weighting was performed mathematically as described in the section “Computations.” The comparisons are based on results originally produced 

by the U.S. Army Corps of Engineers (USACE) FORTRAN software, not the revised results presented in this report. The values were computed from a linear 

regression of the straight numerical average value and the discharge-weighted value for the concentrations where both were available. All regressions were 

performed in R statistical software, version 3.2.1 (R Core Team, 2015). DWA, discharge-weighted average; r2, coefficient of determination; SA, numerical 

average; SC, suspended-sand concentration; FC, suspended-fines concentration; SSC, suspended-sediment concentration. “Fines” refers to sediment that passes 

through a 0.063-millimeter (mm) sieve (US 230 sieve)]

Site Number 

of pairs

Sand model

DWASC=

Sand

r

2

Fines model

DWAFC=

Fines

r

2

SSC model

DWASSC=

SSC

r

2

UPT 130 0.922(SASC)+0.66 0.989 0.965(SAFC)+5.3 0.997 0.960(SASSC)+4.4 0.996

TAR 270 0.855(SASC)+2.9 0.894 0.999(SAFC)−0.4 0.992 0.968(SASSC)+0.52 0.969

ORO 154 0.852(SASC)+2.5 0.922 1.002(SAFC)+0.3 0.999 0.976(SASSC)+2.9 0.991

RDR 64 0.855(SASC)+4.5 0.955 0.991(SAFC)+0.5 0.993 0.915(SASSC)+13.5 0.980

SIM 221 0.885(SASC)+0.81 0.937 0.985(SAFC)+0.3 0.997 0.953(SASSC)+3.2 0.980

WLO 38 0.820(SASC)+0.25 0.988 0.938(SAFC)+6.3 0.989 0.901(SASSC)+11.4 0.989

MCY 36 0.804(SASC)+0.98 0.995 0.955(SAFC)+3.8 0.997 0.894(SASSC)+13.5 0.992

significantly shorter than the interval between measurements. 

Additionally, the approach used to compute the daily 

suspended-sediment loads did not account for bias introduced 

when converting log-scale predicted values to physical units 

(Cohn and others, 1989; U.S. Geological Survey, 1993). 

Further, the algorithm used to model daily suspended-sediment 

loads did not account for hysteresis in the relation between 

suspended-sediment load and stream discharge (Gray and 

Simões, 2008), which has been observed for the Mississippi 

River (Allison and others, 2012; Mossa, 1989). Hysteresis 

weakens the relation between suspended-sediment load and 

stream discharge because equal loads can occur at different 

discharges, or equal discharges can produce different loads 

depending on the timing of the load measurements relative 

to changes in discharge (that is, rising limb or falling limb of 

the hydrograph). Finally, for data furnished by the USACE, 

insufficient metadata were supplied to verify the daily stream 

discharge values in accordance with current USGS policies on 

furnished record (U.S. Geological Survey, 2016).

Recommended Actions for Revising Results: Because the 

sampling design and method of computing daily suspendedsediment discharge in use by the cooperative program did 

not conform to current USGS standard policies and practices, 

the review team determined that the historical data for daily 

suspended-sediment loads and the annual suspended-sediment 

loads computed by summing daily suspended-sediment loads 

should be removed from USGS products. The sampling 

design was likely adequate for computing annual or seasonal 

suspended-sediment loads within acceptable uncertainties 

(Thorne and others, 2008), which would require the use of 

techniques that the review team considered interpretive. Any 

estimation of suspended-sediment loads at any time step based 

on the revised dataset should consider the full range of data 

quality information presented in this report.

Outcomes: USGS data sources that include daily 

suspended-sediment loads are annotated with a watermark or 

errata page to inform users that the daily suspended-sediment 

loads are no longer considered reliable (table 2). 

Field Methods Review

Issues: Suspended sediment must be collected 

isokinetically to produce a representative sample. Three 

issues were identified that could cause sampling to be nonisokinetic. First, overfull bottles could have prevented the 

river water from entering the bottle isokinetically, leading to 

an SSC that was biased high (Edwards and Glysson, 1999). 

Second, samplers that were operated outside the recommended 

operating conditions could have collected non-isokinetic 

samples. Third, USGS crews were known to have collected 

non-isokinetic samples using the Van Dorn sampler. 

Outside the context of the sampling design, the methods 

used to collect samples in the field generally conformed to 

established practices at both agencies. 

Recommended Actions for Revising Results: The review 

team recommended that any available information about 

the isokinetic nature of the field sampling be compiled and 

presented along with the revised results. 

Outcomes: The review team used the guidance from 

the FISP for P-61 and P-63 samplers that pint bottles 

should be filled to a maximum volume of 400 milliliters 

and quart bottles should be filled to a maximum volume of 

730 milliliters to prevent overfilling (Federal Interagency 

Sedimentation Project, n.d.). An analysis of the bottle volumes 

showed that overfilling occurred for 1,007 out of 43,321 total 

bottles collected for the cooperative program during the study 

period. Bottles that were overfilled can be identified from the 
20 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

information in the data release that accompanies this report 

(Norton and others, 2019).

Stream velocity varies over short spatial and temporal 

scales within a stream cross section. Thus, ensuring that 

the P-61 or P-63 samplers were always operated within the 

target velocity ranges was difficult. The USACE field form 

data indicated that 93 bottles had been collected at velocities 

below 1.5 feet per second and 12 bottles had been collected at 

velocities greater than 10 feet per second. Corresponding data 

were not recorded for USGS samples, so it was not possible 

to definitively identify when non-isokinetic samples had been 

collected by USGS crews.

Sufficient data were recorded on USACE field forms for 

some samples after 2006 to quantitatively evaluate whether 

samples were collected under isokinetic conditions. In 2006, 

the USACE adopted a digital field form that contained the 

sampling date, nozzle diameter, bottle location in the cross 

section, sampling duration, and stream velocity at the sampled 

point. The bottle volumes, sampling durations, and stream 

velocity were used to compute the intake efficiency for each 

point-sample bottle according to the method described in 

USGS Office of Surface Water Technical Memorandum 

2013.03 (U.S. Geological Survey, 2013):

b kV IE

tv  , (22) 

where

IE was the intake efficiency, ratio (unitless);

k was a surface area and unit conversion 

factor for the 3/16-inch nozzle, equal to 

0.1841 foot per milliliter (U.S. Geological 

Survey, 2013);

t was the duration that the point sampler was 

open, in seconds; and

v was the stream velocity at the point, recorded 

from the ADCP, in feet per second, and 

other symbols were as described in table 3.

The intake efficiency is exactly 1 (IE=1) if the velocity 

flowing into the sample bottle is the same as the velocity of 

the stream. When the velocities are equivalent, the sampling 

is isokinetic, and there is no bias in the SSC (U.S. Geological 

Survey, 2013). Low intake efficiency indicates sub-isokinetic 

sampling (IE<1), which can cause the SSC to be biased high, 

particularly for sand-sized particles. High intake efficiency 

or super-isokinetic sampling (IE>1) can cause the SSC to 

be biased low (U.S. Geological Survey, 2013). The USGS 

recommends that samples collected with intake efficiency less 

than 0.7 or greater than 1.3 be evaluated for potential bias in 

the sand concentrations (U.S. Geological Survey, 2013). 

The median intake efficiency for 4,209 bottles that were 

collected at stream velocities greater than 1.5 feet per second 

was 0.545. Seventy-three percent of the intake efficiencies 

were less than 0.7 (sub-isokinetic), and 2.5 percent were 

greater than 1.3 (super-isokinetic). Intake efficiency was 

evaluated only for bottles collected after 2006 by USACE field 

crews, and thus these results could not be applied throughout 

the study period. Further, the quality of the velocity estimate 

could not be verified, as instantaneous point stream velocities 

can be highly variable in the field. Despite the fact that it was 

not possible to generalize these observations to point-sample 

bottles for which stream velocity and sampling duration were 

not available, the review suggested that it was possible that 

non-isokinetic sampling had affected at least some of the 

cooperative program results.

The effect of sub-isokinetic sampling is strongly 

dependent on particle size, with coarser particles showing 

a much stronger effect than finer particles (U.S. Geological 

Survey, 2013). For example, at stream velocities of 5 feet 

per second, an intake efficiency of 0.5 would result in an 

estimated 30 percent positive bias for 0.45-mm sand and an 

estimated 20 percent positive bias for 0.15-mm sand; the 

effect on 0.06-mm sand would be negligible (U.S. Geological 

Survey, 2013). Little, if any, sand would be held in suspension 

at velocities less than 1.5 feet per second. Insufficient data 

were available to quantify the impact of sub-isokinetic 

sampling on all of the revised results. However, the review 

team determined that the potential for positive bias in the 

suspended-sand concentrations measured in point-sample 

bottles was greater for bottles that contained significant 

amounts of medium and coarse sand. 

Laboratory Analysis Review

The laboratory methods used by the cooperative program 

were evaluated relative to published methods (Guy, 1969). 

In brief, the review team documented two major deviations 

from standard practices. First, the evaporation method had 

been used without applying a dissolved-solids correction. 

Second, the SSC had been computed from a subsample of the 

fines rather than from the entire fines fraction in the sample. 

The lack of a dissolved-solids correction led to a high bias in 

the reported SSC and percent fines. Using a subsample of the 

fines to compute SSC led to higher uncertainty than is typical 

for other USGS sediment-analysis methods. 

Dissolved Solids

Issues: In the cooperative program laboratory method, the 

evaporation method (Guy, 1969) was used without applying 

a dissolved-solids correction. Dissolved solids are materials 

that pass through a filter but leave a residue when the filtrate 

is evaporated. They occur in many environmental waters 

because of factors such as chemical weathering of geologic 

materials or pollution. Insufficient measurements were made 

to correct the “half fines” mass for the dissolved solids in 

each point-sample bottle. Consequently, the suspended-fines 

concentrations determined through the cooperative program 

method were biased high compared to the true value as 

discussed in the following sections. Because the fines masses 

were biased high, the resulting measurements of percent fines 
Critical Review of Field, Laboratory, and Computational Protocols 21

in the sample were also biased high. The high bias in percent 

fines resulted in inaccurate scaling of the results of the BW 

tube analysis to the results of the sand analysis (eq. 21).

Current USGS guidance on the measurement of SSC 

supports two primary methods: evaporation and filtration 

(Guy, 1969). When the evaporation method is used, a 

correction must be made to adjust the sediment mass for the 

dissolved solids that are present in the residual overlying river 

water that is evaporated along with the suspended sediment, 

unless it can be demonstrated that the correction will not affect 

the SSC by more than 5 percent (Guy, 1969, p. 12). When the 

filtration method is used, no river water is retained in the dish 

that is used to measure the mass of the suspended sediment, 

and consequently a dissolved-solids correction is not required. 

The significance of the dissolved-solids correction to the 

SSC varies with the relative masses of fines and dissolved 

solids in the evaporation dish used to perform the test. The 

dissolved-solids mass in the evaporation dish depends on the 

volume of residual river water in the point-sample bottle after 

decanting and on the environmental concentration of dissolved 

solids in the river water. For river water of a given SSC, the 

fines mass in each bottle is lower when a lower volume of 

river water is collected in the point-sample bottle. Thus, it was 

possible that when pint bottles were used and less river water 

was collected, the impact of the dissolved-solids correction 

would be greater than when quart bottles were used. 

Recommended Actions for Revising Results: The review 

team recommended that the potential magnitude of the impact 

of the dissolved-solids contamination be quantified and that 

the previously published data should be revised if the impact 

of the dissolved-solids contamination had the potential to 

impact the environmental interpretation of the results. 

Outcomes: The review team used written guidelines and 

targeted testing to initially assess the likely magnitude and 

impact of dissolved solids on the cooperative program data. 

The American Society for Testing and Materials method for 

SSC requires that the dissolved-solids correction be applied 

whenever the dissolved-solids concentration is more than 

10 percent of the SSC (American Society for Testing and 

Materials, 2013). Guy (1969, p. 12) provided guidance that, 

when the dissolved-solids concentration and the SSC are 

similar, the dissolved-solids correction affects the accuracy 

of the results by the ratio of the volume of river water in the 

point-sample bottle before decanting to the volume after 

decanting (for example, if a 400-milliliter sample is decanted 

to 20 milliliters and the dissolved solids and SSCs are equal, 

then the dissolved-solids correction is 5 percent of the total 

mass measured in the evaporation dish). 

The review team compared the environmental dissolvedsolids concentration (milligrams per liter, p70300) and SSC 

among samples in the study region for which both parameters 

were reported. The samples used for the comparison of SSC 

and environmental dissolved-solids concentration were 

collected for other USGS programs at WLO and MCY and 

other sites that were not part of the cooperative program 

(STF, MEL, BRG, fig. 1). The SSC and dissolved-solids 

concentration data were retrieved from NWISWeb (U.S. 

Geological Survey, 2018, table 1) for the Atchafalaya River 

(WLO, MCY, MEL) and the Mississippi River (STF, BRG) for 

October 1, 1989, through October 1, 2015. The material used 

to measure the environmental dissolved-solids concentration 

(p70300) was dried at 180 °C, so the dissolved-solids 

concentration was not directly equivalent to the dissolvedsolids correction that would be used in an evaporation 

method analysis, which specifies that the river water be 

dried at 105 °C. However, the two values were expected to 

be comparable. The SSCs were from samples that were not 

subject to the systematic bias that affected the cooperative 

program samples. For the 1,042 sample records that met the 

search criteria (that is, had both dissolved-solids concentration 

and SSC data collected at one of the identified sites, and were 

not collected for the cooperative program), the dissolvedsolids concentration was greater than the SSC for 790 samples. 

The dissolved-solids concentration was 65 milligrams per liter 

greater than the SSC on average. Consequently, the relative 

bias caused by the lack of the dissolved-solids correction 

was anticipated to be greater than the ratio of the volume of 

river water in the point-sample bottle before decanting to 

the volume after decanting, as articulated in Guy (1969). If a 

typical point-sample bottle contained half the overfull volume 

for the bottle type and was decanted to 30 milliliters, then the 

dissolved solids would make up more than 8 percent of the 

measured suspended-sediment mass in quart bottles and more 

than 15 percent in pint bottles. The review team determined 

that this level of impact warranted further analysis.

The review team conducted an exploratory analysis of 

the 51 concurrent pairs of samples collected between 2006 

and 2014 on the lower Atchafalaya River (WLO, MCY) 

for NASQAN and the cooperative program. The dissolvedsolids concentration (p70300) of the NASQAN sample in 

each pair was used to estimate a dissolved-solids correction 

for each cooperative program point-sample bottle, assuming 

a uniform residual river water volume of 30 milliliters. The 

suspended-sediment mass was recomputed by applying the 

estimated dissolved-solids correction, and the estimated SSC 

was computed from the estimated “half fines” mass with the 

cooperative program computational method. The resulting 

estimated SSC was 40 percent lower than the original SSC, 

on average. Further, the estimated SSC more closely matched 

the SSC data for those samples that were collected by the 

NASQAN program on the same day. The exploratory analysis 

suggested that the lack of a dissolved-solids correction to 

sediment masses determined through the evaporation method 

was likely to be significant and that it had the potential to 

explain the observed discrepancies between the two sets of 

samples. 

In March 2015, members of the review team and 

USGS Office of Surface Water personnel conducted targeted 

concurrent sampling in the study area at WLO, MCY, and 

BLC (fig. 1) on the main stem Mississippi River. Comparison 

samples were collected at the same location on the same day 

with both the cooperative program methods and NASQAN 
22 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

program methods, which use depth-integrated EWI sampling 

and the filtration method for determining SSC. Sufficient 

data were collected in the laboratory to correct each pointsample bottle individually for the dissolved solids in the “half 

fines” beaker. Across 70 bottles collected with the cooperative 

program method for four cross-sectional samples collected 

during the concurrent sampling, the average proportion of 

the “half fines” mass that was attributable to the mass of 

dissolved solids was 20 percent. The true “half fines” mass 

was used to compute the SSC with the cooperative program 

computation method for each of the four cross-sectional 

samples. A comparison between the corrected and uncorrected 

SSC showed that the uncorrected SSC was biased high by 

an average of 19 percent. The review team concluded that 

the use of the evaporation method without a dissolved-solids 

correction was a significant source of systematic bias in the 

cooperative program suspended-sediment results. The review 

team found that it was necessary to revise the previously 

published data to account for the omission of the dissolvedsolids correction. A dataset of the cooperative program 

laboratory data was compiled and used to compute revised 

values as documented in this report. 

Particle-Size Distribution 

Issues: The positive bias in the fines mass resulting from 

the lack of dissolved-solids correction in the “half fines” 

analysis led to positively biased results for the particle-size 

distributions that were produced for the cross-sectional 

sample. The percent fines (p70331) was higher than the true 

value because the measured mass of fines included the mass of 

dissolved solids. 

The problem with overreporting the fines mass resulted 

in problems with the other cross-sectional particle-size 

distribution results from the dry sieve/BW tube analysis. 

The fine particle-size distribution results from the BW tube 

analysis were scaled to the sand particle-size distribution 

results on the basis of an inaccurate measurement of the total 

fines mass in the sample (eq. 21). Consequently, the results for 

particle-size distribution for sizes below 0.063 mm were all 

inaccurate.

Recommended Actions for Revising Results: The review 

team determined that the percent fines should be revised. 

Because the USGS did not report the particle-size distribution 

results in publicly available repositories, revised particle-size 

distribution results for other sizes were not computed.

Outcomes: Revised results for percent fines were 

computed and reported as described later in this report. 

Subsampling 

Issues: USGS guidance does not support reporting SSC 

produced from a subsample of the fines because of the high 

uncertainty associated with splitting a suspended-sediment 

sample (Guy, 1969, p. 2). The review team predicted that 

subsampling the fines would increase the uncertainty of the 

SSC computed for each point-sample bottle. The cooperative 

program laboratory method implicitly assumed that the splitter 

always separated the fines in each point-sample bottle into 

two equal-mass fractions (eq. 2). The overall uncertainty 

in the cross-sectional SSC may have been lower than the 

uncertainty in the individual point-sample bottle SSC because 

the error associated with any individual split was independent 

for each bottle; thus, errors in the splits for each individual 

point-sample bottle would have not all occurred in the same 

direction.

Recommended Actions for Revising Results: The review 

team determined that the uncertainty in SSC associated with 

the subsampling of the fines should be quantified.

Outcomes: Physical testing was conducted to assess the 

split quality as described in this report.

Laboratory Method Performance

Issues: Prior to 2015, the performance for the cooperative 

program laboratory method was not fully tested. Laboratory 

method performance for SSC is characterized by assessing 

the sediment recovery rates from samples of known SSC. 

Specifically, the typical amount of sediment mass gained (less 

likely) or lost (more likely) during the laboratory analysis was 

unknown. Sediment loss during handling would result in a 

negative bias in the reported SSC. The review team predicted 

that the use of the splitter could lead to lower recovery of the 

fines relative to methods used for other USGS programs. The 

splitter vanes and chute had a high surface area where fines 

could be retained, and the total rinse volume was constrained 

by the need to not overflow the 100-milliliter beaker that held 

the “half fines” subsample for each bottle. The limited rinse 

volume also had the potential to prevent all of the fines from 

being thoroughly washed off the sand that was retained on the 

sieve as the sediment/water suspension was introduced to the 

splitter. 

Recommended Actions for Revising Results: The review 

team recommended that physical testing of the bias and 

uncertainty of the analytical method, including the splitting 

process, be conducted and the test results provided along with 

the revised suspended-sediment results.

Outcomes: Physical testing of the recovery rates of the 

sand and fines was conducted to quantify the performance of 

the cooperative program laboratory methods as described later 

in this report.

Information Systems Review

Issues: The method of transferring information from the 

field form to the laboratory form, from the laboratory form 

into the SED file, and from the SUM file into QWDATA was 

subject to infrequent but potentially significant transcription 

errors. Additionally, the USACE FORTRAN program did not 

have a clear method for capturing the decisions of reviewers 
Critical Review of Field, Laboratory, and Computational Protocols 23

about the quality of point-sample bottle or cross-sectional 

sample data. The lack of a standard procedure for reviewing 

cooperative program data led to a mix of techniques to review 

and remove bottles from the analysis by various personnel 

over the history of the program. The SED files also did not 

contain a mechanism for reporting annotations from the 

laboratory data sheet that could affect the interpretation of the 

results. 

Many of the stream discharge results were transcribed 

into QWDATA without review for hydrologic context because 

QWDATA was not the primary repository of surface-water 

field measurements used for gaging streams. In some cases, 

the same results were stored or transcribed elsewhere, which 

provided a basis for identifying transcription errors. 

Recommended Actions for Revising Results: The 

review team found that the workflow that included the 

USACE FORTRAN program should be discontinued and 

a new procedure should be used for reviewing the revised 

cooperative program results for SSC and stream discharge. 

Outcomes: The review team established a uniform 

data-review procedure for suspended-sediment and stream 

discharge data and implemented it for reporting the revised 

results. Reported values for instantaneous stream discharge 

were checked for consistency and plausibility with stream 

discharges measured at nearby stream gages, checked for 

consistency with other records of the same data where 

available, and reviewed within environmental and hydrologic 

context (for example, with respect to seasonal patterns and 

storm events). Further, all revised results were electronically 

uploaded to publicly available repositories to eliminate 

problems with transcription errors.

Computations Review

Issues: The USACE FORTRAN program implicitly 

assumed that the cumulative dry sieve sand weight was a more 

accurate measurement of the sand mass in each point-sample 

bottle than was the sand weight from the wet sieve/split step 

(eq. 1). The sand mass from the wet sieve/split step of the 

cooperative program laboratory method was determined by 

the review team to be a better representation of the sand mass 

in each point-sample bottle than the cumulative dry sieve sand 

weight because less handling occurred before the sand was 

measured. 

Insufficient data were available to reliably dischargeweight the revised suspended-sand concentrations on the basis 

of concurrent depth-and-velocity profiles or ADCP data. The 

review team analyzed whether it was possible to compute a 

discharge-weighted average suspended-sand concentration 

from the available data. Two potential methods were identified 

from USGS documents: compositing all of the point-sample 

data from the cross-sectional samples and averaging the 

composite SSC within each vertical. If the verticals were 

spaced at representative intervals within the cross section, 

either of these techniques could be used to estimate a 

discharge-weighted average SSC (Edwards and Glysson, 

1999, p. 51–52). 

Assuming that the verticals were spaced at representative 

intervals, the applicability of either of these computational 

methods depended on the sampling duration used for each 

point-sample bottle during a sampling event. If a uniform 

sampling duration was used for every point-sample bottle in a 

cross-sectional sample, the composite SSC would be close to 

the discharge-weighted average SSC because less water would 

have flowed into the sample bottle in the low-velocity, and 

thus low-discharge, areas of the cross section. Point samples 

collected this way could be mathematically composited to 

produce a discharge-weighted average SSC (Edwards and 

Glysson, 1999, p. 51–52). If a uniform sampling duration 

was used within each vertical but the duration varied among 

verticals, the SSC could be composited within the vertical, and 

the discharge-weighted average SSC could be computed as the 

average of the composite SSC in each vertical (Edwards and 

Glysson, 1999, p. 51–52). If a non-uniform duration was used 

within a single vertical, the SSC would have to be computed 

by numerical average to avoid the effect of variable sampling 

duration on the composite SSC. 

Recommended Actions for Revising Results: The review 

team determined that the sand mass from the wet sieve/split 

step had been measured with a similar procedure as the “sand 

break” analysis performed for other USGS programs (Guy, 

1969) and should be used for computing the revised results. 

Further, the review team recommended that the original forms 

be reviewed to determine if the sampling duration had been 

uniform within or among the verticals for each sampling event 

to determine the best computational method for the revised 

results. The team recommended that a single computation 

method be used for all of the revised results to eliminate 

variability caused by the mixture of computation methods.

Outcomes: The revised results were computed on the 

basis of the wet sieve sand weight, not the dry sieve sand 

weight. The team hypothesized that this change would lead 

to an increase in the reported suspended-sand concentrations 

because the dry sieve sand weight was normally lower than 

the wet sieve sand weight.

In order to determine what aggregation method was most 

appropriate for the revised suspended-sand concentration 

results, the review team compiled the available information 

about the sampling duration. Prior to 2001, no systematic 

data source was found at either agency that included sampling 

duration. In 2001, the USACE adopted a field form that 

included the sampling duration and stream velocity from 

the ADCP for each point-sample bottle in a cross-sectional 

sample. In 2006, the USACE converted this form to a digital 

spreadsheet and routinely sent it to the laboratory along 

with the samples. Field forms for samples collected between 

2001 and 2006 showed that the use of non-uniform sampling 

durations within a single vertical was not uncommon for the 

USACE field crews during this time period. Digital USACE 

field forms showed that after 2006 a uniform sampling 

duration was used exclusively. USGS field crews were trained 
24 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

to use a uniform sampling duration since 1998 or earlier. 

However, it was possible that some USGS field collections 

contained non-uniform durations as field crews modified 

the collection method in response to low stream velocities 

below 1.5 feet per second. The review team concluded that, 

because written documentation showed that non-uniform 

sampling durations were used routinely for some periods 

in the sampling program history and no documentation 

existed for the majority of the cross-sectional samples, a 

single computation could not be used to report the dischargeweighted average suspended-sand concentration for all 

samples. To meet the recommendation that all revised results 

be computed with the same method, all revised suspendedsand concentrations were computed by numerical average. 

Because the numerical average was expected to produce 

suspended-sand concentrations that were biased high relative 

to the discharge-weighted value, a quantitative comparison 

between the composite (approximately discharge-weighted) 

and the numerical average suspended-sand concentrations for 

samples collected with a uniform duration was performed as 

described later in this report.

Reporting Review

Issue: The cooperative program results had been reported 

to QWDATA without making full use of available fields for 

documenting data quality. 

Recommended Actions for Revising Results: The review 

team recommended that the available annotation fields be 

used to report revised results to QWDATA to fully capture 

the outcomes of the data review and revision. Available fields 

included sample comments, result comments, remark codes, 

null qualifier codes, value qualifier codes, and data quality 

indicator codes.

Outcomes: The revised results are stored with comments 

and codes that reflect the data quality. Data users are 

encouraged to use the “one result per row” with “expanded 

attributes” option to retrieve values from NWISWeb (U.S. 

Geological Survey, 2018, table 2) and inspect the sample 

comments, result comments, remark codes, null qualifier 

codes, value qualifier codes, and data quality indicator codes 

when interpreting the revised results.

Methods Used To Revise Results

Many of the review team recommendations 

required further effort to acquire information needed for 

implementation. Physical testing was performed to determine 

the most appropriate method of applying a dissolved-solids 

correction. Physical testing was also used to assess laboratory 

method performance. A complete dataset of original laboratory 

results was assembled and reviewed for logical consistency. 

The point-sample bottle data were reviewed in cross-sectional, 

seasonal, and hydrologic context. Records of stream discharge 

were assembled and used to review the instantaneous stream 

discharge record in hydrologic context. More details of the 

physical testing and data review steps are described in the 

following sections.

Candidate Methods for Dissolved-Solids 

Correction

The review team recommendation that the suspendedfines concentration be corrected for the dissolved solids in 

the “half fines” beaker for each point-sample bottle was 

anticipated to have the greatest impact on the reported results 

across the entire dataset. The team considered three options 

for removing the mass that was attributable to the dissolved 

solids. All of the options involved estimating a revised fines 

mass from one side of the split and then scaling it to the whole 

sample.

One option was to make an assumption about the residual 

volume of river water that was present in each “half fines” 

beaker and pair it with measured or modeled environmental 

dissolved-solids concentration. The validity of this method 

depended on the uniformity of the river-water volume in each 

bottle after decanting as well as the uniformity of the riverwater volume in each beaker after the split. 

A second option was to make an assumption about 

the final rinse water plus river-water volume in each “half 

fines” beaker and then assign the measured dissolved-solids 

concentration from the BW tube analysis to this volume in 

each beaker. The validity of this method depended on the 

uniformity of the rinse volumes on both sides of the split 

across all of the point-sample bottles in the cross-sectional 

sample. 

A third option was to compute the composite mass of 

the fines from the BW tube analysis by summing the fines 

masses recovered in the BW tube analysis and making a 

dissolved-solids correction based on the recorded dissolvedsolids values from the composite subsample. The third option 

did not preserve the ability to estimate the suspended-fines 

concentration for each point-sample bottle and consequently 

did not preserve the ability to compute the aggregate 

suspended-fines concentration by any other method than 

compositing. However, the third option involved the least 

number of assumptions about the stability of laboratory 

methods over time.

All three options for removing the dissolved-solids 

signal depended on assigning an appropriate multiplier to 

account for the effects of the sample splitting process. The 

review team conducted testing at the Baton Rouge Sediment 

Laboratory in August 2015 to determine the best option for 

the dissolved-solids correction. The testing also served the 

purpose of quantifying the laboratory method performance for 

the cooperative program laboratory method in terms of bias 

and uncertainty. 
Methods Used To Revise Results 25

Preparation of Test Samples

Prepared test samples of known sediment mass mixed 

with known volumes of DI water were used to assess the 

mass recovery and split multiplier. Twenty-five test samples 

were internally prepared at the USGS Cascades Volcano 

Observatory (CVO). The samples prepared at CVO are 

designated as “internally prepared” because they were 

prepared by a member of the review team and thus were 

internal to the review process. An additional seven externally 

prepared samples were used from the USGS Quality Systems 

Branch (QSB) Sediment Laboratory Quality Assurance 

(SLQA) Project. Three of the SLQA samples were received as 

wet suspensions, and four were received as dry powders. 

Internally Prepared Test Samples

The 25 target test masses of sand and fines for the 

internally prepared samples were constructed to span the 

normal range of masses recovered from the cooperative 

program samples. A matrix of the 10th, 25th, 50th, 75th, and 

90th percentile sand mass and of the 10th, 30th, 60th, and 90th 

percentile doubled “half fines” mass was constructed from 

the laboratory data. The 5 by 4 matrix produced 20 target test 

masses for preparing samples of known mass. The geometric 

mean of the sand mass and the geometric mean of the doubled 

“half fines” mass were computed and used as the target mass 

to represent typical bottles for five additional test samples, 

which resulted in a total of 25 targets. 

Test samples were prepared from residual sediment 

from two bed-sediment samples that had been collected in 

a California settling basin in 2014. The bed material was 

used because it was readily available, plentiful, and naturally 

separated into a sample that was predominately sand and 

another that was predominately fines. The material was dried 

overnight at 105 °C and dry sieved in a RO-TAP test sieve 

shaker (W.S. Tyler) for 15 minutes. The sand used to prepare 

test samples was created by combining sand retained on the 

0.250-mm, 0.125-mm, and 0.063-mm sieves from the sandier 

sample. The fines used to prepare test samples were the pan 

material from the finer sample. The sand and fines were 

redried at 105 °C and stored in a desiccator until the weighing 

process. 

The test material was transferred into a tared small plastic 

container until the actual mass was as close as possible to the 

predetermined target mass of sand and fines. The actual mass 

of sand and fines in each container was recorded and was 

used as the expected value for method performance testing. 

The container was sealed and shipped to the Baton Rouge 

Sediment Laboratory. At the laboratory, the dry material was 

rinsed into a pint bottle with DI water, and DI water was 

added to make up a final sample volume of 50–120 milliliters. 

This volume represented a typical residual volume of water 

remaining in point-sample bottles after they were decanted.

Externally Prepared Test Samples

QSB uses 0.125- to 0.250-mm-diameter sand particles 

and 0- to 0.050-mm-diameter Arizona Test Dust to prepare 

test samples with well-known expected sand and fines masses. 

Four QSB samples were requested through the QSB doubleblind program and shipped to the Baton Rouge Sediment 

Laboratory as dry powder. The powder was rinsed into quart 

bottles at the Baton Rouge Sediment Laboratory and wetted 

with approximately 75 milliliters of DI water. Three QSB 

samples arrived at the laboratory as wet suspensions as part 

of the standard QSB single-blind SLQA study for fall 2015. 

The wet suspensions were allowed to settle for approximately 

10 days. The suspensions were decanted before pouring 

through the splitter. The supernatant was collected, filtered, 

and weighed because the samples had not undergone a full 

2-week settling period. The filtered supernatant weight was 

added to the total recovered fines for assessing recovery from 

these samples. The QSB supplied the expected masses for the 

externally prepared samples.

Physical Testing

Each test sample was weighed on a macro balance to 

determine the volume of sediment-water suspension that was 

poured through the splitter. This quantity represented the 

volume after decanting in a normal laboratory work flow. 

A tared 100-milliliter beaker was placed on each side of 

the splitter. The test sample was poured through the 3-inchdiameter 0.063-mm sieve onto the splitter as specified by 

the cooperative program laboratory method (fig. 3). The 

initial mass of the suspension on each side of the split was 

recorded by measuring the gross weight of each 100-milliliter 

beaker to the nearest 0.1 gram. The bottle and splitter were 

rinsed according to normal procedures for cooperative 

program samples, which required that the rinse volume 

not overflow the 100-milliliter beakers. The mass of the 

suspension on each side of the split after rinsing was recorded 

by measuring the gross weight of each 100-milliliter beaker a 

second time. 

For the internally prepared samples and dry externally 

prepared samples, the suspension from both sides of the 

splitter was filtered through a tared 40-milliliter perforatedbottom ceramic Gooch crucible (CoorsTek) lined with 

a Whatman grade 934-AH glass microfiber filter (GE 

Healthcare). For the wet externally prepared SLQA samples, 

the suspension on the right side of the splitter was oven dried 

in the 100-milliliter beaker. The fines from the left side of 

the splitter for the three wet SLQA samples were used to 

perform a BW tube analysis for particle-size distribution. The 

total mass recovery from the left side of the splitter for these 

samples was calculated as the sum of the recovered masses 

from the BW tube analysis. 
26 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

The sand was rinsed off the sieve and was either filtered 

or dried in a 100-milliliter beaker. The beakers and crucibles 

containing the sand and fines were dried for approximately 

36 hours at 105 °C, cooled in a desiccator, and weighed to the 

nearest 0.0001 gram. Four different analysts conducted the 

tests. One analyst poured samples into the splitter from the left 

hand; the other three poured from the right hand. The analysts 

pouring the samples through the splitter and weighing the 

dishes did not know the expected masses of sediment in the 

dishes. 

Additionally, 10 grab samples of Mississippi River water 

were collected off a dock at Baton Rouge, La., on August 3, 

2015. Five of the samples were spiked with 0.018–0.019 gram 

of sand on August 14, 2015. These samples were allowed to 

settle in the laboratory until testing was conducted on August 

25–26, 2015. A 100-milliliter aliquot of the supernatant was 

withdrawn and filtered through a glass Gooch crucible fitted 

with a 47-mm Whatman grade 934-AH glass microfiber filter. 

The filtered material represented residual suspended solids 

that might be present after settling had occurred. The filtrate 

was collected, and an 80-milliliter aliquot was pipetted into 

a tared 100-milliliter beaker to determine a dissolved-solids 

correction. The samples were decanted with the vacuum 

system, and their volume after decanting was recorded. The 

decanted samples were split into 100-milliliter beakers on 

each side of the splitter following the standard procedure for 

the cooperative program laboratory method. The post-split 

volume on each side of the splitter was recorded before rinsing 

the splitter. The splitter was rinsed with DI water, and the 

sand was washed off the sieve into a beaker. The supernatant 

from the sand beaker was collected into another tared beaker. 

The dissolved-solids beaker, sand beaker, sand-supernatant 

beaker, fines beakers, and the filter crucible were oven dried at 

105 °C, cooled in a desiccator, and weighed. The mass in each 

fines beaker was corrected for the dissolved solids present in 

the overlying water with the method from Guy (1969), where 

the residual native-water volume was the recorded volume in 

the beaker after the split and before the rinse.

Laboratory method performance was assessed by 

computing the percent recovery for sand, fines, and total 

sediment for each test sample. The percent recovery was 

computed as

  % 100 percent obs

exp

m R

m   , (23)

where

R was the recovery rate, in percent;

mobs was the observed mass of sand, fines, or total 

sediment, in grams; and

mexp was the expected mass of sand, fines, or total 

sediment, in grams.

For environmental samples that were spiked with sand, the 

expected sand mass was the sum of the spiked mass and the 

average sand mass in the unspiked environmental samples 

(0.0014 gram±0.0008 gram, n=5). 

The multiplier for scaling the fines from one side of the 

split to the whole sample was computed by taking the ratio 

of observed fines from both sides of the split to the observed 

fines from one side of the split:

( ) ( )

( )

obs L obs R

L

obs L

m m

K

m

  , and (24)

( ) ( )

( )

obs L obs R

R

obs R

m m

K

m

  , (25)

where

KL was the empirical multiplier for the left side 

of the splitter;

KR was the empirical multiplier for the right side 

of the splitter;

mobs(L) was the observed mass of fines on the left side 

of the splitter, in grams; and

mobs(R) was the observed mass of fines on the right 

side of the splitter, in grams.

To check the assumption that the post-decanted volume 

was predictable, three analysts each used the equipment 

in the Baton Rouge Sediment Laboratory to decant pint 

or quart bottles of DI water. The volumes after decanting 

were measured and combined with similar data collected on 

environmental samples during the March 2015 concurrent 

sampling event and with data from other tests conducted 

in August 2015. Altogether, the post-decanted volumes of 

121 bottles were recorded. The analysts were instructed 

to decant normally, replicating past practices, without 

consciously trying to achieve a uniform residual volume.

Revised Suspended-Fines Concentration 

Computation

The test of the post-decanted residual water volumes 

showed that the assumption that the volumes would be similar 

or predictable was not supported. The range of post-decanted 

volumes for pint bottles was 28.0–117.1 milliliters (n=100); 

the range for quart bottles was 81.4–239.5 milliliters (n=21). 

Further, the values could vary systematically; that is, one 

analyst at one time might decant more or less thoroughly than 

another analyst at another time. Any uncertainty produced 

by the wide range in potential values was not likely to be 

independent from bottle to bottle, so using any volume-based 

method could introduce systematic errors in the outputs. 

Laboratory personnel also indicated that they did not expect 

the assumption of consistent volumes to be borne out over 

time because many different analysts had worked in the 

laboratory. The review team consequently abandoned the 

attempt to correct the “half fines” beakers for dissolved solids 

at an individual-bottle scale. Instead, the review team selected 

the dissolved-solids correction method that used the data from 

the BW tube analysis to compute the revised suspended-fines 

concentration for the composite sample.
Methods Used To Revise Results 27

Because the data from the BW tube analysis were used 

to compute the corrected fines mass, the review team used 

the left-side multiplier, KL in the correction method. The 

observed KL was 2.04±0.16 (median ± interquartile range, 

n=41, table 5). We used this multiplier to scale the composite 

fines from the BW tube analysis to the whole sample after 

correcting the BW tube sediment mass for dissolved solids:

 1 ( ) 50 mL aliquot volume

l dsol

f i BW i wc BW L

m m m  m V K

                      
 
  , and (26)

1  

mg fines mL "water" 1,000 1,000

g fines L "water"

f

f C n

i b i

m C

 V    

, (27)

where

mf was the composite mass of fines in the 

sample, in grams;

l was the number of BW tube withdrawal 

weights collected, always 10;

n was the number of bottles that contributed to 

the composite fines subsample;

KL was the empirically determined multiplier for 

the split, 2.04±0.16 (table 4); and 

Cf C was the composite suspended-fines 

concentration, in milligrams per liter. 

The term “water” indicates river water, which contains water 

and suspended sediment. Other inputs were as described in 

table 3. The volume of the residual water in the suspension, 

VBW, was computed by dividing the net weight of the beaker 

that held the residual water by an assumed density of 1 gram 

per milliliter, equivalent to the density of water (table 3). 

Revised Suspended-Sand Concentration 

Computation 

The suspended-sand concentration for the cross-sectional 

sample was computed by numerical average:

 mg sand mL "water" 1,000 1,000

g sand L "water"

ws

S

b

m C

V    , and (28)

1 ( )

t

i S i

S

C

C

t

   , (29)

where

CS was the average suspended-sand concentration 

in the cross section, in milligrams per liter; 

and 

t was the number of bottles that were accepted 

by reviewers.

Other inputs were as described in table 4. Bottles that 

were rejected by reviewers were simply excluded from the 

computation of the average suspended-sand concentration. 

The wet-sieve sand mass was used to compute the suspendedsand concentrations. 

Revised SSC Computation 

The revised average suspended-sand concentration and 

the revised composite suspended-fines concentration were 

used to compute the revised reported parameters: 

C C S f C C , and (30)

0.063 100 percent

Cf C pf C   , (31) 

where

C was the revised cross-sectional SSC (p80154), 

in milligrams per liter.

The revised suspended-sediment discharge (p80155, short tons 

per day) was computed from the stream discharge (p00061) 

and the SSC as described in equation 6. The revised SSC, 

percent fines, stream discharge, and suspended-sediment 

discharge results are available from NWISWeb (U.S. 

Geological Survey, 2018; table 1). The originally reported 

results and the revised results are provided in a publicly 

accessible data release (Norton and others, 2019) and in 

appendix 4 of this report. 

Estimation of Laboratory Uncertainty

The need to use the split multiplier to scale subsamples 

of the fines to the whole sample meant that any revised values 

had inherently higher laboratory uncertainty than would be 

expected for laboratory results for other USGS programs. 

The cumulative uncertainty associated with the various 

measurements in the laboratory was estimated through the 

use of a Monte Carlo simulation with 10,000 repetitions 

(Joint Committee for Guides in Metrology, 2008). The Monte 

Carlo method was chosen because it was flexible and because 

it was able to model the treatment of the low masses that 

had been observed in samples collected for the cooperative 

program. The standard deviation of the outputs from the 

Monte Carlo analysis was reported as the uncertainty of the 

result. The relative measurement uncertainty was the standard 

deviation of the 10,000 Monte Carlo outputs divided by the 

measurement result.

The Monte Carlo method required that an uncertainty 

distribution be assigned to every input variable. Most 

inputs were net weights; that is, weight computed as the 

difference between a gross weight and a tare weight of a 

dish or bottle. The Baton Rouge Sediment Laboratory could 

not provide sufficient data to verify the standard uncertainty 

associated with a single mass measurement of a 100-milliliter 

beaker. A mass measurement in a 100-milliliter beaker was 

assumed to have a standard uncertainty of ±0.0005 gram, 

which represented an expanded uncertainty (k=2.5) of the 

standard uncertainty on a single measurement of the mass 

of a process blank in a crucible or beaker maintained by 

the laboratory from October 2015 to May 2017 (n=635). 

A process blank is a dish that is tared normally and used to 
28 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 5. Results from physical testing of the splitter used in the U.S. Geological Survey Baton Rouge Sediment Laboratory to process 

samples collected for the cooperative program in the lower Mississippi-Atchafalaya River Basin.—Continued

[“Fines” refers to sediment that passes through a 0.063-millimeter (mm) sieve (US 230 sieve). KL is the ratio of the total fines mass to the fines mass on the left 

side of the splitter. “Percent fines” is percent by mass of the sediment that passes through a 0.063-mm sieve. Asterisk (*) denotes results for which the measured 

mass was within ±0.0015 gram of the expected mass. Sample type: externally prepared sample, U.S. Geological Survey (USGS) Quality Systems Branch 

samples from the Sediment Laboratory Quality Assurance Project; internally prepared sample, fluvial bed material collected from a settling basin in California 

prepared by a member of the review team at USGS Cascades Volcano Observatory; MS River grab sample, grab sample of water from the Mississippi River at 

Baton Rouge, La.; MS River grab sample sand spike, grab sample of water from the Mississippi River at Baton Rouge, La., spiked with sand. Results coded as 

“—” were not relevant to the sample type indicated and so were not available]

Sample type

Expected 

sand mass, 

grams

Sand recovery, 

percent

Expected 

fines mass, 

grams

Fines 

recovery, 

percent

Total 

sediment 

recovery, 

percent 

(eq. 23)

KL,

unitless 

ratio

(eq. 24)

Difference 

from expected 

percent fines, 

percentage 

points

Externally 

prepared (dry) 

sample 

0.0000 (−0.0005 gram)* Known error in pour through the splitter

0.0303 137 0.0253 124 126 2.00* −1.6

0.0327 1 0.1203 66 53 1.90 19.6

0.0224 85 0.1299 95 94 2.06 1.0

Externally 

prepared (wet) 

sample1

0.0300 107 0.2025 92 95 2.43 −2.8

0.1702 97 0.1005 91 92 2.23 −1.0

0.1707 97 0.7508 87 89 2.12 −1.6

Internally 

prepared 

sample

0.0014 36* 0.7508 89 87 1.99* 2.5

0.0022 109* 0.0320 106 107 1.93* −0.2

0.0068 101* 0.0252 103* 103 1.98* 0.2

0.0210 100* 0.0250 97* 98 2.12* −1.0

0.0494 97 0.0268 103* 99 2.04* 1.3

0.0006 200* 0.0266 95 96 1.91 −1.3

0.0028 111* 0.0510 102* 103 2.21 −0.4

0.0080 99* 0.0495 99* 99 1.93 0.0

0.0190 94* 0.0403 92 92 2.10 −0.5

0.0478 94 0.0408 94 94 2.11 0.2

0.0013 77* 0.0425 92 92 2.14 0.3

0.0030 83* 0.0634 92 91 2.04* 0.4

0.0078 87* 0.0613 95 94 1.98* 0.8

0.0213 88 0.0619 97 94 2.08 1.8

0.0480 84 0.0623 94 90 1.94 2.7

0.0010 150* 0.0659 94 94 2.01* −0.5

0.0019 116* 0.1073 92 93 2.04 −0.4

0.0078 113* 0.1072 91 92 1.93 −1.5

0.0211 82 0.1097 79 79 1.95 −0.6

0.0491 97 0.1083 100* 99 1.98* 0.8

0.0102 88* 0.0643 99* 98 2.02* 1.3

0.0108 97* 0.0641 100* 99 1.98* 0.3

0.0103 83 0.0639 99* 97 1.97* 1.9

0.0111 84 0.0667 94 92 1.97 1.3

0.0086 98* 0.0699 95 96 1.89 −0.2

Table 5. Results from physical testing of the splitter used in the U.S. Geological Survey Baton Rouge Sediment Laboratory to process 

samples collected for the cooperative program in the lower Mississippi-Atchafalaya River Basin.

[“Fines” refers to sediment that passes through a 0.063-millimeter (mm) sieve (US 230 sieve). KL is the ratio of the total fines mass to the fines mass on the left 

side of the splitter (eq. 24). “Percent fines” is percent by mass of the sediment that passes through a 0.063-mm sieve. Asterisk (*) denotes results for which the 

measured mass was within ±0.0015 gram of the expected mass. Sample type: externally prepared sample, U.S. Geological Survey (USGS) Quality Systems 

Branch samples from the Sediment Laboratory Quality Assurance Project; internally prepared sample, fluvial bed material collected from a settling basin in 

California prepared by a member of the review team at USGS Cascades Volcano Observatory; MS River grab sample, grab sample of water from the Mississippi 

River at Baton Rouge, La.; MS River grab sample sand spike, grab sample of water from the Mississippi River at Baton Rouge, La., spiked with sand. Results 

coded as “—” were not relevant to the sample type indicated and so were not available]
Methods Used To Revise Results 29

Table 5. Results from physical testing of the splitter used in the U.S. Geological Survey Baton Rouge Sediment Laboratory to process 

samples collected for the cooperative program in the lower Mississippi-Atchafalaya River Basin.—Continued

[“Fines” refers to sediment that passes through a 0.063-millimeter (mm) sieve (US 230 sieve). KL is the ratio of the total fines mass to the fines mass on the left 

side of the splitter. “Percent fines” is percent by mass of the sediment that passes through a 0.063-mm sieve. Asterisk (*) denotes results for which the measured 

mass was within ±0.0015 gram of the expected mass. Sample type: externally prepared sample, U.S. Geological Survey (USGS) Quality Systems Branch 

samples from the Sediment Laboratory Quality Assurance Project; internally prepared sample, fluvial bed material collected from a settling basin in California 

prepared by a member of the review team at USGS Cascades Volcano Observatory; MS River grab sample, grab sample of water from the Mississippi River at 

Baton Rouge, La.; MS River grab sample sand spike, grab sample of water from the Mississippi River at Baton Rouge, La., spiked with sand. Results coded as 

“—” were not relevant to the sample type indicated and so were not available]

Sample type

Expected 

sand mass, 

grams

Sand recovery, 

percent

Expected 

fines mass, 

grams

Fines 

recovery, 

percent

Total 

sediment 

recovery, 

percent 

(eq. 23)

KL,

unitless 

ratio

(eq. 24)

Difference 

from expected 

percent fines, 

percentage 

points

MS River-grab 

sample

— — — — — 2.02* —

— — — — — 2.16 —

— — — — — 2.17* —

— — — — — 2.05* —

— — — — — 2.10* —

MS River-grab 

sample, sand 

spike

0.0202 83 — — — 2.32 —

0.0201 77 — — — 2.60 —

0.0195 97* — — — 2.55 —

0.0196 64 — — — 2.21 —

0.0201 74 — — — 2.43 —

Median: 96 — 95 94 2.04 0.2

Interquartile 

range:

±17 — ±7 ±7 ±0.16 ±1.7

1

The subsamples from the left side of the splitter for the three wet SLQA samples were processed through the bottom-withdrawal (BW) tube. The recovery 

was the sum of the masses recovered from the BW tube analysis.

process a prepared sample of DI water that is inserted into 

the batch by the analyst. The gross weight of the dish is 

recorded with others in the batch. As long as the net weight 

of the blank shows no significant presence of sediment in 

the dish, the difference between the gross and tare weights 

represents the measurement uncertainty due to dish handling 

and environmental factors in the laboratory during weighing. 

The expanded uncertainty accounted for variability in dish 

handling methods over time and the difference in surface area 

between the beakers and the crucibles, which could lead to a 

stronger signal from environmental factors for beakers. 

Each net weight was the difference of two weights. The 

standard uncertainty of the net weights for the Monte Carlo 

analysis was computed as

 2

2 net dish u u   , (32)

where 

unet was the uncertainty of a single net weight, in 

grams; and

udish was the uncertainty of a single dish weight, 

in grams, assumed to be a constant 

0.0005 gram. 

The distribution for each net weight used as an input was 

constructed by creating a set of 10,000 normally distributed 

values with a mean equal to the measured net weight and a 

standard deviation equal to unet. When the observed net weight 

was low, the distribution sometimes included negative net 

weights. Negative net weights were reassigned to zero to 

mimic the laboratory practice of adjusting slightly negative net 

weights to zero during weighing. The uncertainty analysis was 

conducted with R statistical software version 3.2.1 (R Core 

Team, 2015). 

The uncertainty of the overall composite fines value 

depends on uncertainty introduced by the splitter, the number 

of bottles that contributed to the composite fines subsample, 

and the relative mass of fines in each bottle. A biased split 

for a bottle with a large amount of fines would have had a 

stronger effect on the composite value than would a biased 

split for a bottle with a small amount of fines. For each 

sample, the number of bottles was known, but the amount of 

fines contributed by each bottle was unknown. To estimate an 

uncertainty for KL, we assumed that a single bottle dominated 

the split so that the distribution of the composite-scale KL

was similar to the observed distribution of bottle-scale KL. 

This assumption provided a conservative estimate of the 

uncertainty on the composite suspended-fines concentration. 
30 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

If all of the bottles in a sample contained similar masses of 

fines, the actual uncertainty would be lower than the reported 

uncertainty.

The distributions for the other inputs were constructed 

from normal distributions with estimated standard deviations. 

For the bottle net weight, a similar technique was used as 

described in equation 32, with an assumed uncertainty for a 

bottle mass measurement of ±1.0 gram. The macro balances 

weigh to the nearest 0.1 gram, so this was a conservative 

estimate of the uncertainty for a bottle mass measurement. 

The volume of the dissolved-solids aliquot in the BW tube 

analysis was assumed to be 50±0.2 milliliters. The density of 

river water was assumed to be 1.000±0.005 grams per cubic 

centimeter (Guy, 1969). The density of the decanted composite 

subsample used in the BW tube analysis was assumed to 

be 1.000±0.010 grams per cubic centimeter. The expanded 

uncertainty in the density accounted for the unknown, 

but potentially significant, sediment concentration in the 

suspension.

Historical Sediment Data 

The correction method required that the review team 

compile a complete set of historical original laboratory data 

because the information required for the computation could 

not be inferred from the previously published data alone. The 

original laboratory data were also used to correct transcription 

errors and review the results in a robust and consistent manner.

Digitized input files (SED files) and primary laboratory 

spreadsheets (Excel files) were recovered from USGS and 

USACE servers and imported into an SQL Server 2008 R2 

database. Primary laboratory paper records were retrieved 

from USACE and USGS archives, scanned, and cataloged 

so that they could be linked to their corresponding digitized 

data. When a primary paper form could not be linked to a 

digitized dataset, the laboratory data were digitized from the 

paper form into a blank laboratory spreadsheet and imported 

into the project database. Paper forms or digital primary data 

sources were recovered for 2,867 of 2,895 cross-sectional 

samples collected during the period covered by this report. 

For the 28 cross-sectional samples where SED files existed 

but no primary data could be recovered, revised results were 

computed if the digitized data in the SED files passed the 

other checks described below. 

To link input data with their originally reported values, 

data from the project sites were retrieved from QWDATA 

with the internal NWIS Reporting Application in 2015. The 

QWDATA information was downloaded in text files and 

imported into the project database.

After all of the data were assembled into the project 

database, the digitized laboratory data, QWDATA record, 

and scanned laboratory data sheet were linked by site, date, 

and time. When the times were unknown or conflicting, the 

records were linked by site and date. It was rare that more 

than one sample was collected for the cooperative program 

at a single site on the same day, which is why this method of 

linking data was used. Records of samples that had site and 

date values that did not match any other record were checked 

to see if they had transcription errors in the date by comparing 

the values for fields other than site, date, and time to the 

values for the same fields in other records. If the QWDATA 

record was determined to have an incorrect date or time, the 

QWDATA record was updated. Where the correct time could 

not be ascertained, the sample was recorded to have been 

collected at noon, which was likely close to the true sampling 

time since nearly all of the samples were collected between 

10 a.m. and 2 p.m. 

Each cross-sectional sample had either one or no 

QWDATA record. It was not possible to determine if samples 

with no QWDATA record had been rejected by reviewers 

or omitted inadvertently. Samples that had no matching 

QWDATA record were added to QWDATA during the upload 

of revised values if they passed the other data quality checks 

(table 6). 

A single cross-sectional sample could have multiple 

digital representations (for example, scanned original, SED 

files, Excel file, QWDATA record). For example, SED files 

deliberately duplicated the first and last samples of each 

water year. Both a SED file and an Excel file existed for most 

events since 2001. In some cases, both the USACE and the 

USGS servers contained SED files for a given sample. Data 

technicians sometimes prepared multiple SED files for a 

sample with different discharge values (that is, conventional 

discharge or ADCP discharge) or reflecting the decisions of 

different reviewers. 

When all of the fields used in the recomputation of the 

results were identical among all of the digital representations 

of a sample, any of the representations could be used as 

the final data for the sample. When there was conflicting 

information in the multiple representations, the review team 

compared the conflicting values to the primary laboratory 

data sheet to determine the correct final data for the sample. 

The end result of this cleanup step was that each sample 

was associated with one final digital representation of its 

laboratory data, which was then evaluated for further quality 

checks.

It was not possible to exhaustively verify every digitized 

laboratory value against its value on the primary laboratory 

data sheet. Instead, the review team applied a series of 

logical checks to the final data to identify fields that might 

be in error (table 6). The logical checks were implemented 

with structured query language (SQL) queries against the 

database. The review team confirmed fields that failed these 

logical checks against the primary data and updated the 

values if they were in error. If a sample failed a check even 

after all transcription errors were corrected, the team made a 

determination about whether to accept or reject that sample on 

a case-by-case basis. 

In addition to the logical checks, the team reviewed the 

suspended-sand concentrations for each point-sample bottle in 

cross-sectional spatial context. Graphs were prepared for every 

sample showing each point-sample bottle at its recorded depth 
Methods Used To Revise Results 31

Table 6. Logical checks performed against final sample data with structured query language (SQL) queries to identify possible 

transcription errors in data recorded for samples collected between October 1989 and February 2015 for the cooperative program in the 

lower Mississippi-Atchafalaya River Basin. 

[The logical checks were used to identify possible transcription errors. Samples that failed logical checks after correcting transcription errors were reviewed on a 

case-by-case basis. BW, bottom-withdrawal; <, less than; %, percent] 

Analysis Description Variable name 

(table 3)

BW tube All 10 BW weights present, positive, and non-null BWW

All 10 BW weights <0.9999 gram BWW

Dissolved-solids correction <0.0125 gram1 BWDS1

Each successive BW weight within 0.0010 gram of previous weight or declining BWW

Wash correction not more than 10% of total BW mass BWWC

No single BW weight more than 40% of the sum of all of the BW weights for the cross-sectional sample BWW

No single BW weight less than 1% of the sum of all of the BW weights for the cross-sectional sample BWW

Residual BW volume between 35 and 500 milliliters BWVOL

Sand Wet-sieve sand weights for all bottles are non-null and between 0 and 0.9999 gram SANDW

Wet-sieve sand weight greater than dry sieve sand weight for all bottles SANDW, US230

Dry-sieve sand weight at least half of the wet sieve sand weight, or within 0.0050 gram SANDW, US230

Bottle volume All bottles have a non-null, positive volume TVOL

The recorded volume can be contained by the bottle2 TVOL

The bottle volume is not too low2 TVOL

Split The sum of the BW weights plus the wash correction is not more than 0.0150 gram larger than the sum 

of the “half fines” weights3

BWW, BWWC, 

HFINE

1

A dissolved-solids correction greater than 0.0125 gram in 50 milliliters (250 milligrams per liter) was higher than most of the recorded environmental total 

dissolved solids (TDS) values for this system; the BWDS was expected to have a lower concentration than the TDS because it contained both river water and 

deionized water used to rinse the splitter.

2

For 11 bottles where the volume was out of range, the suspect volume was replaced with the average bottle volume for the set before computing the revised 

values. These bottles have a review code of “s” in the data release that accompanies this report (Norton and others, 2019).

3

Because the majority of the dissolved solids in the composite subsample were removed when the composite subsample was decanted, it was normal for the 

sum of the BW weights to be less than the sum of the “half fines” weights.

and horizontal position in the cross section. The graphs were 

symbolized with a color ramp and text annotation to indicate 

the suspended-sand concentration in each point-sample bottle. 

Any point-sample bottle that would change the composite 

suspended-sand concentration by more than 10 milligrams per 

liter if rejected was symbolized with a thick border (fig. 5). 

A Portable Document Format (PDF) document was 

created for each site in R statistical software, version 3.2.1 

(R Core Team, 2015), showing the graphs in order by 

sampling date at each site. Review team members inspected 

each sample for the environmental plausibility of the 

suspended-sand concentrations in cross-sectional context, 

taking into account their understanding of sampling practices 

and spatial and seasonal patterns at each site. Suspendedsand concentrations could have been implausibly high if the 

sediment sampler struck the river bottom during collection, 

especially for deep samples. Sometimes a bottom strike could 

result in residual sand in the nozzle, which could contaminate 

the next sample collected at the top of an adjacent vertical. 

Reviewers also identified bottles where the suspended-sand 

concentration was implausibly low, possibly as the result of 

something blocking the nozzle during collection. Suspect 

bottles were first checked for transcription errors in the 

sand mass or bottle volume. When a reviewer determined 

that a bottle was implausibly high or low in sand, the bottle 

was annotated accordingly and removed from subsequent 

computations of suspended-sand concentration. The review 

team rejected 381 bottles for implausible suspended-sand 

concentrations out of 43,321 total bottles.

The cross-sectional graphs (example in fig. 5) were 

also used to correct significant errors in the cross-sectional 

positions of the point-sample bottles and to identify samples 

that had missing bottles when compared to the target sampling 

design for the site. Data for specific bottles could have been 

missing for multiple reasons, including unusually high or 

low sediment mass, breakage, or inadvertent omission. It was 

difficult to identify the reason because the only tool that had 

been available for removing rejected bottles in the USACE 

FORTRAN program was to delete the row for the bottle from 

the SED file. To ensure a uniform review, the missing bottle 

data were added to the database from the primary paper form 

and reviewed in cross-sectional context to determine whether 

inclusion was appropriate. 
32 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

1,500 2,000 2,500 3,000 3,500

60

50

40

30

20

10

0

Distance from reference point, in feet

Depth of sample, in feet

25

32

24

33

56

22

24

118

43

239

25

85

103

130

328

18

33

38

73

169

328

18

Point-sample bottle suspended-sand

concentration—In milligrams per liter

Depth of vertical

Composite suspended-sand

concentration change—More than

10 milligrams per liter if rejected by

reviewers

EXPLANATION

Figure 5. Example graph used to review sand concentrations in cross-sectional context for samples collected for the cooperative 

program between October 1989 and February 2015 in the lower Mississippi-Atchafalaya River Basin. Point samples collected for 

suspended-sediment concentration and particle-size distribution are shown in their X-Y (horizontal-depth) locations in the cross 

section. All of the bottles depicted in the figure were accepted by the review team.

The USACE FORTRAN program did not provide a 

field for comments about the laboratory analysis. Various 

treatments of observations such as “glass particles observed” 

or “algae in sample” were used by different digitizers at 

different times. Every scanned primary laboratory data sheet 

was visually inspected for these types of comments. When 

notes were found, the bottle data were annotated accordingly, 

and if appropriate, the bottle was removed from the 

subsequent suspended-sand analysis.

At the end of the sediment data cleanup, the final 

representation of each cross-sectional sample matched the 

primary laboratory data. The point-sample bottle data and 

BW tube data had been checked for logical consistency, 

transcription errors had been corrected, and the point-sample 

bottle data had been reviewed in cross-sectional context. 

Instantaneous Stream Discharge 

The purpose of the instantaneous stream discharge review 

was to determine the most representative instantaneous stream 

discharge (p00061) results to use in computing instantaneous 

suspended-sediment discharge (p80155) for each sampling 

event. The reported values are not intended for use in 

computing ratings for gages in the study region. 

For all sites, the results in QWDATA for instantaneous 

stream discharge (p00061) were first verified against the most 

original form of the result. In order of preference, the most 

original result was

1. The primary field form, or a scanned copy of the field 

form.

2. The primary laboratory data sheet, or a scanned copy of 

the laboratory data sheet.

3. Electronic data transcribed from the field form or 

laboratory data sheet, if originals were not available.

Two other sources of discharge data were used to check 

the reported p00061 values in QWDATA: USGS field 

measurements and USACE-hosted instantaneous discharges 

(table 2). Additionally, reported values for p00061 were 

checked to determine if they matched the stream discharge 

that was used to compute the instantaneous suspendedsediment discharge (p80155) from the reported SSC (p80154) 

(eq. 6). 

For events in which a measurement had been recorded in 

the field measurements section of the USGS NWIS database 

(table 2), the value in QWDATA p00061 was verified against 

this measurement. Measurements were not recorded in the 

field measurements section for all samples because the 

field measurements section is a part of the USGS reporting 

structure and was not used by the USACE. When there was 

a discrepancy between the QWDATA p00061 value and the 

value in the field measurements section of the NWIS database 

for an event, the field measurement was used because it had 

undergone fewer transcription steps and was considered 

more reliable.

For some sites, stream discharge data had been collected 

by the USACE and transcribed into QWDATA by USGS staff. 

In these instances, results in QWDATA were verified against 

the USACE-hosted data. In addition, the USACE results 

were reviewed for continuity and environmental plausibility 

by visual inspection of the hydrograph, comparison to 
Corrected SSC and Related Results 33

hydrographs from nearby sites, and comparison to independent 

measurements where possible, in accordance with USGS 

policies for the review of furnished record (U.S. Geological 

Survey, 2016).

All discharge results, and especially results with 

discrepancies among multiple sources, were checked against 

the longer term hydrograph for that site and nearby sites 

to verify that the result was representative for the time of 

day during which sample collection occurred, depending 

on whether the hydrology showed rising limb or falling 

limb conditions. This check was also used as a test of 

reasonableness to identify and correct transcription errors.

All results were also verified for correct rounding. If a 

result had been misrounded and additional significant digits 

were available, the rounding was corrected to three significant 

digits, which was the defined precision for stream discharge in 

QWDATA.

At TAR, the Tarbert Landing site (fig. 1, table 1), data 

for p00061 in QWDATA had been manually entered from 

the USACE once-daily data collected at noon from USACE 

station 01100Q, which is colocated with the suspendedsediment cross section. Stream discharge values at USACE 

station 1100Q were computed from stages recorded at a 

gage at Red River Landing, approximately 4 river miles 

downstream (fig. 1). The original results in QWDATA were 

found to have several transcription errors. Rather than fix 

these errors on an individual basis, the USACE data were 

downloaded from the USACE website (U.S. Army Corps of 

Engineers, 2017) and used to populate the results for p00061 

in QWDATA.

At ORO, the Old River Outflow site (fig. 1, table 1), data 

for p00061 were compared to data collected at 8 or 9 a.m. 

from the USACE station 02600Q, which is colocated with 

ORO2 (fig. 1, table 1), to identify any results that had been 

affected by large errors in data entry. If results for p00061 

were missing from all other data sources, the USACE result 

was used.

At SIM, the Simmesport site (fig. 1, table 1), data for 

p00061 were compared to data collected at 8 or 9 a.m. from 

the USACE station 03045Q to identify any results that had 

been affected by large errors in data entry. If results for 

p00061 were missing from all other sources, the USACE 

result was used.

At RDR, the Red River site (fig. 1, table 1), results for 

p00061 were compared to the differences of the USACE daily 

stream discharge measurements collected at SIM and ORO 

(SIM minus ORO) to identify and correct any results affected 

by large errors in data entry or errors in sampling date. 

At MCY, the Morgan City site, and WLO, the Wax 

Lake Outlet site (fig. 1, table 1), results from both sites were 

evaluated for proportionality to each other and to USACE 

station 03045Q at SIM to identify any results that had been 

affected by large errors in data entry or misidentifications of 

sampling date or location. Suspected errors were resolved 

by reviewing all data sources relative to the longer term 

hydrograph stream discharge data for these sites.

At UPT, the Union Point site (fig. 1, table 1), no 

measurements were recorded in the field measurements 

section of the database, and several sampling events lacked 

primary field forms with recorded results for discharge. 

Some cross-sectional samples that had not been recorded 

in QWDATA appeared to have been collected from a 

nearby site on the Mississippi River that was downstream 

of the Old River Outflow Channel and therefore were not 

representative of the UPT site. These samples were rejected 

for UPT on the basis of the hydrologic data and other 

annotations in the field notes. Discrete data for p00061 

at UPT were compared to the sums of the USACE daily 

measurements collected at TAR and ORO. These checks were 

useful in identifying large errors in data entry and errors with 

sampling dates. 

At high flows, the comparison of UPT to TAR+ORO 

showed that the reported discharge at UPT was below 

that predicted by the TAR+ORO value. The review team 

determined that, when the value of TAR+ORO discharge 

was greater than 1,120,000 cubic feet per second, the 

flow at UPT was not well constrained within the stream 

banks. Consequently, stream discharge at UPT tended to be 

underreported at these higher flows. The originally reported 

stream discharges were measured from bank to bank and 

an estimate added for the overbank flow. The estimate 

appeared to be low relative to the stream discharge that was 

predicted on the basis of the hydrologic analysis. A linear 

regression model of the relation between UPT and TAR+ORO, 

{UPT=[(TAR+ORO) × 0.9813] + 6182.4, r2=0.9872, n=316}, 

was used to calculate estimates of stream discharge for 

47 events with higher flows at UPT. The estimated stream 

discharge was used to estimate the suspended-sediment 

discharge for these 47 cross-sectional samples (eq. 6). The 

suspended-sediment discharge is based on the SSC measured 

in the channel because no sampling was conducted in the 

overbank portion of the flow. If the overbank flow carried less 

suspended sediment than did the channel flow, suspendedsediment discharge estimated with this method could be 

higher than the true value. Both the stream discharge and the 

suspended-sediment discharge are annotated with a remark 

code that indicates they are estimated; data users should 

be aware that results for these cross-sectional samples are 

likely less reliable than for samples where the flow was well 

constrained by the channel. 

Corrected SSC and Related Results

Revised results for the stream discharge and suspendedsediment parameters are presented in appendix 4 and are 

publicly available through NWISWeb (U.S. Geological 

Survey, 2018, table 2) and in the data release that accompanies 

this report (Norton and others, 2019). The environmental 

impact of the change in reported results could be described 

by quantifying the amount by which the originally reported 
34 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

results were biased relative to the revised results. The bias in 

the originally reported results could be quantified in either the 

original units or in relative terms:

 b o X X ld  new, and (33) 

100 percent b

r

new

b

X

   , (34) 

where

b was the difference between the old and new

results, in their original units (that is, 

milligrams per liter or short tons per day); 

Xold was the originally reported result; 

Xnew was the revised result; and

br was the relative bias in the original result, in 

percent.

The relative bias in samples where the revised result was low 

could be high, even if the absolute change due to the revision 

was of minimal environmental impact (for example, if SSC 

was revised from 10 milligrams per liter to 5 milligrams 

per liter, the relative bias was 100 percent). Conversely, 

the relative bias in a high value could be low even when 

the environmental change might be large (for example, if 

suspended-sediment discharge was revised from 450,000 short 

tons per day to 400,000 short tons per day, then the relative 

bias was 12.5 percent, but the environmental effect was a 

reduction in estimated suspended-sediment discharge of 

50,000 short tons per day). Where one value provided more 

relevant information, we have discussed that value in the text. 

Data users can derive either value for any specific sample 

from the data release that accompanies this report (Norton and 

others, 2019).

A second method of quantifying the effect of the revision 

could be used to describe the apparent change in the result due 

to the revision, again in either the original units or in relative 

terms:

 c n X X ew  old , and (35) 

100 percent c

r

old

c X

   , (36) 

where

c was the “absolute change” defined as the

difference between the new and old results, 

in their original units (that is, milligrams 

per liter or short tons per day); and

c was the relative change from the original 

result, in percent.

The relative change was negative when the result was 

revised downward. The absolute value of the relative change 

was usually less than the absolute value of the relative bias 

because the originally reported values for suspended-sediment 

parameters were usually larger than their corresponding 

revised values. The relative change is less environmentally 

relevant than the relative bias, so it is not discussed 

extensively in the text. However, the information about the 

change is presented in tables and can be computed from the 

information in the data release that accompanies this report 

(Norton and others, 2019).

Change in Reported SSC

The revised SSC was lower than the originally reported 

SSC for 94 percent of the 2,361 cross-sectional samples 

that had both a revised and an original SSC. Sites on the 

lower Atchafalaya River (MCY, WLO) were more strongly 

affected than were sites on the main stem Mississippi River 

(UPT, TAR) (fig. 6, table 7). However, the location of the 

site was not the only factor that affected the strength of the 

downward revision. Samples that were collected in pint 

bottles were revised downward more strongly than were 

samples that were collected in quart bottles. Because some 

sites were collected exclusively in pint bottles whereas 

others were collected exclusively in quart bottles, it was not 

possible to separate the effect of the bottle type from the effect 

of the site. 

The median relative bias in the originally reported 

SSC was 59 percent for samples collected in pint bottles 

(n=768) and 23 percent for samples collected in quart 

bottles (n=1,593). The median absolute change in SSC was 

−66 milligrams per liter for samples collected in pint bottles

and −40 milligrams per liter for samples collected in quart

bottles. Pint bottles contained less suspended-sediment mass

than did quart bottles for the same SSC, so the impact of

the dissolved-solids contamination was greater for samples

collected in the pint bottles than for those collected in the

quart bottles.

The comparison of revised to original SSC incorporates 

the effect of all of the changes that were implemented by 

the review team, not just the dissolved-solids correction. 

However, the dissolved-solids signal was the main source of 

systematic bias in the previously reported SSC. For all tables, 

the records for UPT1/UPT2 and ORO1/ORO2 (table 1) have 

been combined because the two sampling locations represent 

the same hydrologic node in the system.
Corrected SSC and Related Results 35

UPT(Q) TAR(Q) RDR(Q) ORO(Q) ORO(P) SIM(Q) SIM(P) MCY(P) WLO(P)

Site (bottle type)

−200

0

200

400

600

800

1,000

1,200

Relative bias in reported suspended-sediment concentration, in percent

316 459 119 322 62 377 54 327 325

EXPLANATION

32 Number of values

Individual value above the

 90th percentile

90th percentile

75th percentile

50th percentile

 (median)

25th percentile

10th percentile

Individual value below the

 10th percentile

Figure 6. Relative bias in reported suspended-sediment concentration for samples collected for the cooperative program between 

October 1989 and February 2015 in the lower Mississippi-Atchafalaya River Basin. The relative bias is computed as described in 

equation 34. For sites (fig. 1, table 1) where samples were collected in pint (P) and quart (Q) bottles, separate boxes are shown for both 

bottle types. Further details of the change are presented in table 7.

Uncertainty of SSC

The measurement uncertainty for the original and revised 

SSC results incorporated the uncertainty that was introduced 

by the mass measurements and the split. Though no formal 

data quality objectives existed for measurement uncertainty, 

the review team believed that relative measurement 

uncertainty in SSC below 10 percent or 10 milligrams per liter 

would indicate that the revised results were acceptably precise. 

The relative measurement uncertainty met these criteria for all 

but 1 of the 2,697 cross-sectional samples for which revised 

SSC was reported. The measurement uncertainty for the 

revised SSC and percent fines are reported in the data release 

that accompanies this report (Norton and others, 2019). 

Other sources of uncertainty arise from unmeasured 

handling steps such as potential drips or incomplete rinses of 

the sieve. The measurement uncertainty is therefore a lower 

limit of the true uncertainty for the entire laboratory process. 

There were not sufficient data available to quantify the whole 

process uncertainty over the life of the program. 
36 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 7. Summary statistics for the relative bias in suspended-sediment concentration and the absolute change in suspendedsediment concentration by site and bottle type for samples collected between October 1989 and February 2015 for the cooperative 

program in the lower Mississippi-Atchafalaya River Basin. 

[Percentiles were computed by using the default quantile algorithm in R statistical computing software, version 3.2.1 (R Core Team, 2015). %, percent; Q, quart 

bottle; P, pint bottle]

Site code1 Bottle type Count 10th% 25th% 50th% 75th% 90th%

Relative bias in original suspended-sediment concentration results, percent (eq. 34)

UPT Q 316 5.6 15.0 26.2 42.9 63.7

TAR Q 459 0.8 10.9 19.3 32.8 54.6

RDR Q 119 −7.7 3.3 15.3 34.1 110.9

ORO Q 322 8.7 17.4 29.5 52.6 82.0

ORO P 62 19.0 35.8 66.7 110.4 154.9

SIM Q 377 0.0 8.8 20.8 36.7 76.4

SIM P 54 27.8 45.6 87.3 178.7 220.4

MCY P 327 15.6 29.9 58.1 133.1 249.6

WLO P 325 17.3 27.3 54.0 119.0 229.5

Absolute change from original suspended-sediment concentration results, milligrams per liter (eq. 35)

UPT Q 316 −81 −59 −43 −30 −16

TAR Q 459 −71 −54 −40 −24 −2

RDR Q 119 −102 −52 −22 −7 19

ORO Q 322 −77 −58 −43 −26 −12

ORO P 62 −113 −87 −70 −54 −40

SIM Q 377 −73 −53 −38 −22 −0.2

SIM P 54 −178 −114 −83 −58 −43

MCY P 327 −143 −97 −67 −48 −32

WLO P 325 −125 −88 −62 −43 −33

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).

Change in Reported Percent Fines

The revised percent fines was lower than or equal to 

the originally reported percent fines for 93 percent of the 

2,361 cross-sectional samples that had both a revised and an 

original percent fines. Only the absolute change is reported 

for particle-size results because the reporting units are already 

scaled relative to the sample mass; the relative change in a 

relative value is difficult to interpret. The absolute change 

in the percent fines was similar across all sites and both 

bottle types (fig. 7, table 8). The overall median change in 

the percent fines was −4 percentage points. The effect of the 

revision was weaker for percent fines than for SSC because 

cross-sectional samples with very large relative changes in 

SSC usually had little to no suspended sand, so the resulting 

percent fines was still very close to 100 percent even when the 

SSC was revised strongly downward. 

Change in Reported Instantaneous Stream 

Discharge

At most sites the revised instantaneous stream 

discharge was similar to the original instantaneous stream 

discharge, and the review process corrected transcription 

errors or resolved conflicts among multiple data sources. 

Correction of transcription errors and the resolution of 

conflicts among data sources resulted in a few large changes 

to the reported discharge, but there was no overall trend of 

upward or downward revision except for the 47 samples 

collected at high flows at the UPT site, subsite UPT2 (fig. 1, 

table 1). At UPT2, a regression model was used to estimate 

stream discharges when the TAR+ORO discharge on the 

same day was greater than 1,120,000 cubic feet per second. 

The effect of extrapolating the UPT2 discharge was that 

the originally reported discharges were revised upward 

for the high-flow events. The median upward revision for 

the 47 extrapolated discharges was 140,000 cubic feet per 

second (10th percentile=20,000 cubic feet per second, 

and 90th percentile=336,000 cubic feet per second). The 

regression model was also used to estimate discharges for 

UPT for three additional events where no original discharge 

data could be recovered. The modeled discharges are 

annotated as estimates in the reported data. 
Corrected SSC and Related Results 37

Site (bottle type)

UPT(Q) TAR(Q) RDR(Q) ORO(Q) ORO(P) SIM(Q) SIM(P) MCY(P) WLO(P)

−100

 −50

 0

 50

 100

Absolute change in percent fines, in percentage points

315 459 119 322 62 377 54 327 325

EXPLANATION

32 Number of values

Individual value above the

 90th percentile

90th percentile

75th percentile

50th percentile

 (median)

25th percentile

10th percentile

Individual value below the

 10th percentile

Figure 7. Absolute change in percent fines for samples collected between October 1989 and February 2015 for the cooperative 

program in the lower Mississippi-Atchafalaya River Basin. The absolute change is computed as described in equation 35, where 

the original units are percent. “Percent fines” refers to the percent by mass of the sediment that passes through a 0.063-millimeter 

sieve (US 230 sieve), which is reported on U.S. Geological Survey parameter 70331. For sites (fig. 1, table 1) where samples have been 

collected in pint (P) and quart (Q) bottles, separate boxes are shown for both bottle types. One sample that had an originally reported 

percent fines greater than 100 percent was excluded from the visualization.

Table 8. Summary statistics for the absolute change in reported percent fines by site and bottle type for samples collected between 

October 1989 and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[“Percent fines” is percent by mass of the sediment that passes through a 0.063-millimeter (mm) sieve (US 230 sieve). Percentiles were computed by using the 

default quantile algorithm in R statistical computing software, version 3.2.1 (R Core Team, 2015). %, percent; Q, quart bottle; P, pint bottle]

Site code1 Bottle type Count 10th% 25th% 50th% 75th% 90th%

Absolute change from original percent fines, percentage points (eq. 35)

UPT Q 316 −11 −8 −5 −2 0

TAR Q 459 −11 −8 −5 −3 0

RDR Q 119 −13 −8 −4 −1 1

ORO Q 322 −9 −6 −3 −1 0

ORO P 62 −13 −9 −5 −3 −1

SIM Q 377 −11 −7 −5 −2 0

SIM P 54 −19 −10 −5 −3 −1

MCY P 327 −10 −7 −3 −1 0

WLO P 325 −10 −5 −3 −1 0

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).
38 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Change in Reported Suspended-Sediment 

Discharge

The revised suspended-sediment discharge was lower 

than the originally reported suspended-sediment discharge for 

92 percent of cross-sectional samples. The relative bias in the 

originally reported suspended-sediment discharge was similar 

to the relative bias in the originally reported SSC (tables 7 

and 9) because there was not a clear pattern of upward or 

downward revision for most instantaneous stream discharge 

values. The sites on the main stem Mississippi River (UPT, 

TAR) had a smaller relative bias in the SSC (fig. 6, table 7), 

but a higher instantaneous stream discharge (fig. 8), than 

did the other sites. Consequently, the absolute change in 

suspended-sediment discharge was greater at these two sites 

than at the other sites (fig. 9, table 9). The revision resulted 

in a median change in the suspended-sediment discharge of 

−62,000 short tons per day at UPT, −49,700 short tons per day 

at TAR, −3,800 short tons per day at RDR, −17,500 short tons 

per day at ORO, −22,600 short tons per day at SIM, −24,000 

short tons per day at MCY, and −15,900 short tons per day at 

WLO (fig. 9, table 9). Both the relative bias (eq. 34) and the 

relative change (eq. 36) are reported for suspended-sediment 

discharge for the convenience of data users (table 9).

Table 9. Summary statistics for the relative bias in suspended-sediment discharge, the absolute change in suspended-sediment 

discharge, and the relative change in suspended-sediment discharge by site for samples collected between October 1989 and February 

2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[Percentiles were computed by using the default quantile algorithm in R statistical computing software, version 3.2.1 (R Core Team, 2015). %, percent; Q, quart 

bottle; P, pint bottle]

Site code1 Bottle type Count 10th% 25th% 50th% 75th% 90th%

Relative bias in original suspended-sediment discharge results, percent (eq. 34)

UPT Q 316 2.4 10.5 24.9 41.9 62.8

TAR Q 459 −1.2 9.2 19.2 33.0 57.7

RDR Q 119 −7.6 3.6 15.6 34.2 113.0

ORO Q/P 384 8.6 18.4 33.1 58.4 106.6

SIM Q/P 431 −4.1 9.1 23.4 48.0 104.1

MCY P 327 16.0 30.0 58.3 133.9 254.1

WLO P 325 16.7 26.8 53.8 119.3 229.3

Absolute change from original suspended-sediment discharge results, short tons per day (eq. 35)

UPT Q 316 −145,000 −101,000 −62,000 −33,900 −8,500

TAR Q 459 −125,000 −82,000 −49,700 −22,000 3,200

RDR Q 119 −36,000 −12,900 −3,800 −695 8,400

ORO Q/P 384 −47,600 −29,000 −17,500 −9,590 −3,600

SIM Q/P 431 −54,600 −35,900 −22,600 −10,800 10,000

MCY P 327 −53,400 −34,100 −24,000 −15,400 −7,910

WLO P 325 −37,000 −24,200 −15,900 −10,000 −5,000

Relative change from original suspended-sediment discharge results, percent (eq. 36)

UPT Q 316 −38.6 −29.5 −19.9 −9.5 −2.4

TAR Q 459 −36.6 −24.8 −16.1 −8.4 1.2

RDR Q 119 −53.0 −25.5 −13.5 −3.5 8.3

ORO Q/P 384 −51.6 −36.9 −24.9 −15.6 −7.9

SIM Q/P 431 −51.0 −32.5 −19.0 −8.4 4.3

MCY P 327 −71.8 −57.2 −36.8 −23.1 −13.8

WLO P 325 −69.6 −54.4 −35.0 −21.2 −14.3

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).
Corrected SSC and Related Results 39

UPT TAR RDR ORO SIM MCY WLO

Site

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

Revised instantaneous stream discharge, in cubic feet per second

372 538 179 488 538 381 381

EXPLANATION

90th percentile

75th percentile

50th percentile

(median)

25th percentile

10th percentile

32 Number of values

Figure 8. Revised instantaneous stream discharge from measurements that were made concurrently with cross-sectional suspendedsediment samples at each site in the lower Mississippi-Atchafalaya River Basin for the periods of revised record, October 1989 through 

February 2015. The plotted values are for individual instantaneous stream discharge measurements and should not be used to infer the 

total stream discharge through these sites (fig. 1, table 1), which requires more frequent time-series data.

Change in Suspended-Sand Discharge

The original suspended-sand discharge was compared to 

the revised suspended-sand discharge to assess the potential 

effect of the revision on models of sand transport in the 

system. The suspended-sand discharge in short tons per day 

was computed from the originally reported and the revised 

results by

 0.063

3

s L short tons 1 0.0027

100 day ft mg sand

pf Q C Q              

, (37) 

where

Qsand was the calculated suspended-sand discharge, 

in short tons per day;

C was either the revised cross-sectional SSC 

(eq. 30) or the originally reported crosssectional SSC (CD [eq. 17] or C [eq. 5]), in 

milligrams per liter;

pf0.063 was either the revised or original percent fines 

in percent; and

Q was either the revised or original 

instantaneous stream discharge, in cubic 

feet per second. 

Overreporting the amount of fines in the system caused a 

high bias in both the SSC and the percent fines. However, 

the percentage of suspended sand is computed as the inverse 

of the percent fines, so the percentage of suspended sand 

was biased low. Thus, the computation used to produce 

the suspended-sand discharge with the originally reported 

values was a product of values that were biased in opposite 

directions. 

The overall change in the suspended-sand discharge as 

a result of the revision was weakly positive, with the revised 

values being similar to the original values for most samples. 

For 76 percent of events, the revised value for suspendedsand discharge was higher than the original value, with the 

median change ranging from 202 short tons per day at RDR to 

1,860 short tons per day at TAR to (fig. 10, table 10). Within 

that general pattern, some events had large revisions to their 

sand discharge, usually as the result of major changes to the 

reported instantaneous stream discharge or to bottles being 

added or removed by the contextual review. Only the absolute 

change in suspended-sand discharge is shown in table 10 

because the relative bias and relative change could not be 

computed when the revised suspended-sand discharge was 

zero short tons per day.
40 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Site

UPT TAR RDR ORO SIM MCY WLO

−200,000

−150,000

−100,000

 −50,000

 0

 50,000

Absolute change in instantaneous suspended-sediment

discharge, in short tons per day

316 459 119 384 431 327 325

EXPLANATION

90th percentile

75th percentile

50th percentile

(median)

25th percentile

10th percentile

32 Number of values

Figure 9. Absolute change between the revised values and the originally reported values of instantaneous suspended-sediment 

discharge for samples collected between October 1989 and February 2015 for the cooperative program in the lower MississippiAtchafalaya River Basin. The absolute change is computed as described in equation 35. The boxplot is shown without the points below 

the 10th or above the 90th percentiles for visual clarity. The outlying points had a wide range because transcription errors, though 

relatively infrequent, could produce factor-of-10 errors in the reported values, which created wide tails in the absolute differences. The 

values shown are for instantaneous (discrete) measurements of suspended-sediment discharge only and should not be used to infer

total suspended-sediment load in the system without additional analysis. See figure 1 and table 1 for site codes and locations.

Change in Population-Scale Summary Statistics

The change from the originally reported results to the 

revised results could be computed for only the 2,361 crosssectional samples for which original and revised results 

existed. There were an additional 174 cross-sectional samples 

that were rejected during the review for which original 

results existed but not revised results. Conversely, there were 

an additional 336 cross-sectional samples that were added 

during the review for which revised results existed but not 

original results. To include these cross-sectional samples in the 

before-and-after comparison, population-scale statistics were 

computed for the original results and revised results without 

directly comparing them for each cross-sectional sample 

(tables 11 and 12). The remaining 24 cross-sectional samples 

had no originally reported results and no revised results 

because they were rejected by the review team.

The population-scale analysis supported the conclusions 

(1) that the outcome of the revision was to shift sediment 

parameters downward and (2) that the shift was likely of 

environmental significance. For example, at TAR, the median 

SSC was 227 milligrams per liter for the original results and 

187 milligrams per liter for the revised results (table 11). This 

−40 milligram per liter change in the median SSC resulted 

in a change in the median suspended-sediment discharge of 

−63,000 short tons per day (original median=378,000 short 

tons per day; revised median=315,000 short tons per day) 

(table 12). On the Atchafalaya River at SIM, the median 

SSC was 226 milligrams per liter as originally reported and 

162 milligrams per liter for the revised results (table 11). This 

−64 milligram per liter change in the median SSC resulted 

in a change in the median suspended-sediment discharge of 

−38,000 short tons per day (original median=143,000 short 

tons per day; revised median=105,000 short tons per day) 

(table 12). The TAR and SIM sites represent hydrologic 

nodes that provide information about the suspended-sediment 

available in the lower Mississippi and Atchafalaya Rivers 

(figs. 1 and 2), which helps inform management decisions in 

the region.
Corrected SSC and Related Results 41

Site

UPT TAR RDR ORO SIM MCY WLO

−20,000

−10,000

 0

 10,000

 20,000

 30,000

 40,000

Absolute change in suspended-sand discharge, in short tons per day

315 459 119 384 431 327 325

EXPLANATION

90th percentile

75th percentile

50th percentile

(median)

25th percentile

10th percentile

32 Number of values

Figure 10. Absolute change in the computed instantaneous suspended-sand discharge for samples collected between October 1989 

and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. The original instantaneous suspendedsand discharge was computed from the reported parameters (eq. 37). The absolute change is computed as described in equation 

35. The boxplot is shown without the points below the 10th or above the 90th percentiles for visual clarity. The outlying points had a 

wide range because transcription errors, though relatively infrequent, could produce factor-of-10 errors in the reported values, which 

created wide tails in the absolute differences. The absolute change in suspended-sand discharge as the result of the revision for most 

events was weakly positive. See figure 1 and table 1 for site codes and locations.

Table 10. Summary statistics for the absolute change in suspended-sand discharge by site for samples collected between October 

1989 and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[Percentiles were computed by using the default quantile algorithm in R statistical software, version 3.2.1 (R Core Team, 2015). One sample was removed from 

this computation because its originally reported percent finer than 0.063 millimeter was greater than 100 percent. %, percent; Q, quart bottle; P, pint bottle]

Site code1 Bottle type Count 10th% 25th% 50th% 75th% 90th%

Absolute change from original suspended-sand discharge results, short tons per day (eq. 35)

UPT Q 315 −13,100 −96 1,430 7,440 33,100

TAR Q 459 −14,900 −882 1,860 11,400 25,600

RDR Q 119 −2,760 2 202 1,580 14,100

ORO Q/P 384 −1,490 −31 289 933 2,250

SIM Q/P 431 −484 154 786 4,080 23,900

MCY P 327 −108 39 416 1,280 3,780

WLO P 325 −66 34 314 847 2,260

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).
42 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 11. Population-scale summary statistics for original and revised results for suspended-sediment concentration for samples 

collected between October 1989 and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[Percentiles were computed by using the default quantile algorithm in R statistical software, version 3.2.1 (R Core Team, 2015). %, percent]

Site code1 Bottle type Result type Count 10th% 25th% 50th% 75th% 90th%

Population-scale summary statistics for original and revised suspended-sediment concentrations, milligrams per liter 

UPT Quart Original 332 123 163 218 279 375

Revised 354 76 118 166 242 325

TAR Quart Original 481 136 175 227 295 379

Revised 515 94 135 187 255 343

RDR Quart Original 140 73 97 190 395 615

Revised 171 39 65 142 314 610

ORO Both Original 412 116 144 187 238 316

Revised 457 64 96 132 189 256

SIM Both Original 477 131 166 226 342 493

Revised 488 61 102 162 273 413

MCY Pint Original 346 100 153 214 301 387

Revised 357 35 61 124 202 305

WLO Pint Original 347 95 144 204 275 350

Revised 355 35 62 121 190 274

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).

Table 12. Population-scale summary statistics for original and revised results for suspended-sediment discharge for samples 

collected between October 1989 and February 2015 for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[Percentiles were computed by using the default quantile algorithm in R statistical software, version 3.2.1 (R Core Team, 2015). %, percent]

Site code1 Bottle type Result type Count 10th% 25th% 50th% 75th% 90th%

Population-scale summary statistics for original and revised suspended-sediment discharge, short tons per day 

UPT Quart Original 332 110,000 209,000 421,000 664,000 898,000

Revised 354 65,400 135,000 326,000 580,000 816,000

TAR Quart Original 481 101,000 193,000 378,000 567,000 758,000

Revised 515 62,500 135,000 315,000 489,000 667,000

RDR Quart Original 140 3,890 8,430 50,000 177,000 303,000

Revised 156 2,340 5,990 26,200 121,000 296,000

ORO Both Original 412 23,100 41,100 80,000 129,000 202,000

Revised 457 12,900 28,100 58,400 104,000 167,000

SIM Both Original 477 31,000 66,100 143,000 275,000 424,000

Revised 488 16,700 42,900 105,000 237,000 386,000

MCY Pint Original 346 17,400 35,500 81,700 149,000 245,000

Revised 356 5,830 14,200 45,500 100,000 184,000

WLO Pint Original 347 11,600 23,600 53,500 93,000 145,000

Revised 355 4,190 10,200 34,600 67,600 110,000

1

The three-letter site codes are a convention used only in this report (table 1, fig. 1).
Critical Evaluation of Revised Results 43

Critical Evaluation of Revised Results

After the revised results were computed, the review 

team evaluated the revised results for bias and uncertainty, 

independent of their change relative to the originally 

reported results. Specifically, the review team evaluated 

available sources of information about the effect of the SSC 

computation method that was used to calculate the revised 

cross-sectional SSC from the point-sample bottle results, the 

effect of laboratory practices on the revised suspended-fines 

concentration, and the bias and uncertainty in the revised SSC. 

Effect of SSC Computation Method 

The revised SSC was the sum of the average suspendedsand concentration and the composite suspended-fines 

concentration (eq. 30). Neither value was technically discharge 

weighted. Discharge-weighted SSC should be used to compute 

suspended-sediment discharge (Edwards and Glysson, 

1999). The review team assessed the potential impact of the 

computation method on the applicability of the revised SSC to 

computation of suspended-sediment discharge. 

Suspended-Sand Concentration

The revised suspended-sand concentrations were 

computed by numerical average (eq. 30). For the originally 

reported results, prior investigation had shown that numerical 

averaging produced a positive bias in the suspended-sand 

concentration of 8–20 percent relative to the dischargeweighted average (table 4). The relation between the 

numerical average suspended-sand concentration and the 

discharge-weighted average suspended-sand concentration 

depended on site-specific and sample-specific factors such as 

the sampling design (number and arrangement of sampling 

verticals and depths) and the stream discharge during 

sampling. There were not enough data to quantify the effects 

of sampling design for every arrangement used at each site 

across the entire study period. 

For cross-sectional samples collected in water year 

2006 and thereafter, USACE crews documented a uniform 

sampling duration for every bottle in the cross section. Over 

the same period, USGS crews had been trained to use a 

uniform sampling duration. Further, the sampling effort and 

cross-sectional locations of the verticals had been stable over 

this period. When the sampling duration was uniform for all 

of the point-sample bottles in a cross-sectional sample, the 

composite suspended-sand concentration was expected to be 

close to the discharge-weighted suspended-sand concentration. 

For these 830 cross-sectional samples, the composite 

(approximately discharge-weighted average) suspended-sand 

concentration ranged from 89.7 percent to 99.5 percent of 

the straight numerical average suspended-sand concentration 

(table 13). The slopes less than 1 (m<1) indicated that 

the numerical average suspended-sand concentration was 

higher than the composite suspended-sand concentration. 

However, the difference between the composite suspendedsand concentration and the numerical average suspendedsand concentration was less than 10 milligrams per liter for 

799 out of these 830 cross-sectional samples. Although the 

findings from the recent cross-sectional samples could not 

be applied with confidence across the entire study period, 

they suggested that the bias caused by using the numerical 

average suspended-sand concentration for the revised results 

was constrained and that the practice of numerical averaging 

produced suspended-sand concentrations that were useful for 

the purposes of estimating suspended-sand discharge.

Table 13. Linear regression models between composite suspended-sand concentration and average suspended-sand concentration 

for the 830 cross-sectional samples collected since October 1, 2005, for which revised suspended-sand concentration is reported for 

samples collected for the cooperative program in the lower Mississippi-Atchafalaya River Basin. 

[The models are from a linear regression of the numerical average suspended-sand concentration and the composite suspended-sand concentration. All 

regressions were performed in R statistical software, version 3.2.1 (R Core Team, 2015). CSSC, composite suspended-sand concentration, in milligrams per 

liter; SASC, numerical average suspended-sand concentration, in milligrams per liter; r2, coefficient of determination]

Sampling location1 Number of pairs Composite suspended-sand 

concentration model CSSC= r2

UPT 117 0.995(SASC)−0.38 0.992

TAR 161 0.995(SASC)−0.82 0.989

ORO1 70 0.918(SASC)+0.63 0.993

ORO2 93 0.960(SASC)−0.25 0.996

SIM 154 0.935(SASC)+0.69 0.996

WLO 116 0.989(SASC)−0.03 0.998

MCY 119 0.897(SASC)+0.13 0.996

1

The sampling location is described in table 1.
44 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Suspended-Fines Concentration

The impact of the computation method on the SSC was 

predicted to be weaker for suspended fines than for suspended 

sand. In most systems, the suspended-fines are well mixed 

spatially through the cross section (Edwards and Glysson, 

1999, p. 2; U.S. Subcommittee on Sedimentation, Interagency Committee on Water Resources, 1963, p. 28 and 33). 

Under this condition, almost any field sampling technique 

will produce a reasonable representation of the suspendedfines concentration. There was no direct way to quantify the 

effect of using the composite suspended-fines concentration 

for the revised results because it was not possible to compute 

the suspended-fines concentration by any method other than 

compositing (eq. 27). Indirect evidence from the originally 

reported results suggested that the discharge-weighted 

suspended-fines concentration was 93.8 percent to 100 percent 

of the numerical average suspended-fines concentration 

(table 4). The suspended-fines concentrations used in this 

comparison were computed prior to the correction for the 

presence of dissolved-solids contamination. Of the 913 pairs 

of originally reported discharge-weighted and numerical 

average suspended-fines concentrations, 844 had a difference 

of less than 10 milligrams per liter. These observations 

supported the use of the composite suspended-fines discharge 

for computing the revised SSC.

Effect of Laboratory Practices on Revised 

Suspended-Fines Concentrations

The revised suspended-fines concentrations depended 

on the applicability of the split multiplier, KL, measured 

experimentally in 2015, to samples collected over the 

entire study period (eq. 27). No data were available to 

directly determine whether the details of the splitting 

procedure for environmental samples had been precisely 

consistent through time. Observations of the laboratory 

methods suggested that there could be effects associated 

with the splitter itself, such as the levelness of the splitter, 

the placement of the splitter on the laboratory bench, or 

the physical condition of the splitter. The review team also 

anticipated that there could be analyst-specific differences in 

the method of introducing the sediment-water suspension to 

the splitter, the thoroughness of the rinse, or the frequency of 

drips and spills. To characterize the applicability of using KL

values for the entire study period, an indirect estimate of the 

stability of the laboratory technique over time was computed 

by comparing the sum of the “half fines” masses to the fines 

mass recovered from the composite subsample for each 

sampling event. We defined the mass difference across the 

sides of the split for each sample as 

1

n m m dif f   i h  m f

, (38) 

where

mdif was the difference in the masses recovered 

from the left and right sides of the splitter, 

in grams;

mf was the fines mass recovered from the 

composite subsample (eq. 26), in grams; 

n was the number of point-sample bottles in the 

cross-sectional sample; and

mhf was the “half fines” mass in each pointsample bottle (table 3), in grams.

Under ideal conditions, the sum of the “half fines” and the 

composite subsample fines masses would be equal, and mdif

would be equal to zero. 

The observed mdif was affected by many factors, many 

of which depended on laboratory technique. Because mdif

compares the composite fines mass after the dissolved-solids 

correction to the composite fines mass before the dissolvedsolids correction, it is influenced by the environmental 

dissolved-solids concentration, decanting technique, and the 

number of point-sample bottles collected for a cross-sectional 

sample. Further, mdif is affected by the splitting technique. 

If a change in the evenness of the split occurs, mdif changes 

because more sediment is recovered from one side of the split 

than was typical before the change. Changes to the evenness 

of the split could have occurred, for example, by the splitter 

being moved within the laboratory or when the laboratory was 

moved from one building to another in 1993. Similarly, if a 

change in the handling for either the “half fines” or BW tube 

steps occurs, the mass recovery rate for fines on one side of 

the split changes, and this causes mdif to change. 

The review team checked mdif for changes over time to 

provide an indirect assessment of the stability of the laboratory 

technique (fig. 11). The purpose of the assessment was to look 

at the long-term, broad-scale trends in mdif, not to evaluate 

the observed mdif for any individual cross-sectional sample. 

Because mdif incorporated environmental effects, sampling 

design effects, and laboratory handling effects, the review 

team knew that some individual samples could have an mdif

value that was unusually high or low. Based on a Loess 

visualization (smwrGraphs R package version 1.1.1, DeCicco, 

2016, span=0.3), mdif declined from 1990 to 1997 and then 

remained stable from 1997 to 2015 (fig. 11). Individual 

cross-sectional samples sometimes had an mdif value that 

was far from the central tendency of the observed results, 

including 18 samples with mdif greater than 0.5 gram or less 

than −0.5 gram that are not displayed on the figure so that the 

results from the remaining 2,679 samples can be displayed in 

detail (fig. 11). The visualization suggested that the methods 

used in the cooperative program had been stable since at least 

1997. Revised suspended-fines concentration results from 

1990 to 1997 may be affected by factors that caused more 

fines to be recovered from the BW tube analysis than was 

typical for samples that were collected after 1997.
−0.5−0.4−0.3−0.2−0.1

 0.0 0.1 0.2 0.3 0.4 0.5

Difference in the masses recovered from the bottom-withdrawal (BW) tube

and "half-fines" analyses,mdif, over time, in grams

1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 

Sample date

EXPLANATION

 Long-term trend Cross-sectional sample

Figure 11. Difference in the masses recovered from the bottom-withdrawal (BW) tube and “half fines” analyses, mdif (eq. 38), over time. The long-terby using Loess regression with a span of 0.3 in the smwrGraphs package version 1.1.1 (DeCicco, 2016) in R statistical software, version 3.2.1 (R Core Twith mdif less than −0.5 gram or greater than 0.5 gram were excluded from the visualization to ensure that the variation in mdif for the remaining 2,679 ccould be displayed in detail.
46 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Information About Bias and Uncertainty in 

Revised SSC

The physical testing as a part of the program review in 

2015 was the first documented direct assessment of sediment 

recovery rates for the cooperative program laboratory method. 

The sediment laboratory protocols and resulting recovery 

rates can be affected by the decanting technique, dish 

handling technique, rinse effort, attentiveness of the analyst, 

oven maintenance, balance maintenance, and desiccator 

maintenance. Although the laboratory method was stable over 

time, as documented, it is possible that changes to the details 

of the method implementation occurred over the 1989–2015 

period for which revised data are provided. 

Method performance in terms of total sediment recovery 

observed during the physical testing conducted in August 2015 

was found to be comparable to the method performance for 

analyses conducted for other USGS programs by the Baton 

Rouge Sediment Laboratory. The median mass recovery rate 

for the test samples processed with the cooperative program 

method was 94±7 percent (median ± interquartile range, n=31, 

table 5). The corresponding recovery rate for similar-mass 

single-blind SLQA samples processed by the laboratory from 

2008 to 2017 with other methods was 96±3 percent (median 

± interquartile range, n=60, U.S. Geological Survey, 2017). 

The three samples (externally prepared-wet, table 5) that were 

processed in the BW tube had recovery rates similar to the rest 

of the test samples, suggesting that the handling involved in 

the BW tube analysis likely did not cause significantly lower 

recovery rates than did the handling used for the other test 

samples. 

Overall, the revised results from the cooperative program 

method are expected to be comparable to results produced by 

other USGS laboratory methods, but with higher uncertainty. 

All traditional laboratory methods for SSC consistently show 

a slight negative bias (American Society for Testing and 

Materials, 2013; Gordon and others, 2000; Gray and others, 

2000; Guo, 2006; Nordqvist and others, 2014; U.S. Geological 

Survey, 2017). Results reported from sediment laboratories 

are not quantitatively adjusted for bias caused by sediment 

recovery rates lower than 100 percent. End users of any 

sediment data should consider whether the laboratory bias 

and uncertainty could affect the conclusions of the project and 

account for the bias and uncertainty, if necessary. 

Conclusions

The revised results for SSC, percent fines, instantaneous 

stream discharge, and instantaneous suspended-sediment 

discharge are the outcome of a number of improvements to 

data quality. The stream discharge data have been thoroughly 

reviewed in hydrologic context and updated where necessary. 

The suspended-sand concentrations have been reviewed in 

cross-sectional, seasonal, and site-specific context with a 

consistent process. Transcription errors have been corrected. 

While these factors affect some individual samples very 

strongly, the most significant overall effect is caused by 

removing the dissolved-solids mass from the suspended-fines 

concentrations. The dissolved solids affected the suspendedfines concentration for every sample, with a stronger effect 

on samples that were collected in pint bottles than on those 

that were collected in quart bottles because of the lower 

suspended-sediment mass collected in pint sample bottles. 

Most of the suspended-sediment results for samples 

collected from October 1989 through February 2015 were 

originally biased high and were revised downward (SSC 

[p80154], 2,182 samples; suspended-sediment discharge 

[p80155], 2,182 samples; percent fines [p70331], 2,010 

samples). The median relative bias in the originally reported 

SSC was

• 26.2 percent for samples collected in quart bottles 

at UPT, 

• 19.3 percent for samples collected in quart bottles 

at TAR, 

• 15.3 percent for samples collected in quart bottles 

at RDR, 

• 29.5 percent for samples collected in quart bottles 

at ORO, 

• 66.7 percent for samples collected at pint bottles 

at ORO,

• 20.8 percent for samples collected in quart bottles 

at SIM, 

• 87.3 percent for samples collected in pint bottles 

at SIM, 

• 58.1 percent for samples collected in pint bottles 

at MCY, and 

• 54.0 percent for samples collected in pint bottles 

at WLO.

The TAR and SIM sites represent hydrologic nodes that 

provide information about the suspended sediment available 

in the lower Mississippi and Atchafalaya Rivers, which helps 

inform management decisions in the region. The median 

revised suspended-sediment discharge for October 1989 

through February 2015 at TAR was 315,000 short tons per day, 

compared to 378,000 short tons per day as originally reported. 

At SIM, the median revised suspended-sediment discharge for 

October 1989 through February 2015 was 105,000 short tons 

per day, compared to 143,000 short tons per day as originally 

reported. Most of the downward revision was due to a change 

in the suspended-fines concentration; the concentration and 

discharge of suspended sand in the system are similar to the 

previously reported values.
References Cited 47

Overall, the revised results from the cooperative program 

method are expected to be comparable to results produced by 

other USGS laboratory methods, but with higher uncertainty 

than is typical for data associated with samples collected by 

using USGS methods. The results have been coded in longterm data repositories to reflect this fact by adding a comment 

that refers data users to this report. However, the review team 

believes that the improvement resulting from the removal of 

known problems outweighs the loss of precision in the reported 

results. End users of the data should take into account the 

sources of bias and uncertainty described in this report when 

developing models of sediment dynamics in the study region.

References Cited

Allison, M.A., Demas, C.R., Ebersole, B.A., Kleiss, B.A., 

Little, C.D., Meselhe, E.A., Powell, N.J., Pratt, T.C., and 

Vosburg, B.M., 2012, A water and sediment budget for the 

lower Mississippi-Atchafalaya River in flood years 2008–

2010: Implications for sediment discharge to the oceans 

and coastal restoration in Louisiana: Journal of Hydrology, 

v. 432–433, p. 84–97, accessed July 19, 2016, at http://www.

sciencedirect.com/science/article/pii/S0022169412001205.

American Society for Testing and Materials, 2013, D-3977 

standard test for determining sediment concentration in water 

samples: West Conshohocken, Pa., ASTM International.

American Society for Testing and Materials, 2014, Test 

sieving methods: Guidelines for establishing sieve analysis 

procedures, 5th edition: West Conshohocken, Pa., ASTM 

International.

Brunner, G.W., 2016 HEC-RAS River Analysis System user’s 

manual, version 5.0: Davis, Calif., U.S. Army Corps of 

Engineers Hydrologic Engineering Center, 960 p.

Buchanan, T.J., and Somers, W.P., 1969, Discharge 

measurements at gaging stations: Techniques of WaterResources Investigations of the United States Geological 

Survey, book 3, chap. A8, 65 p.

Cohn, T.A., DeLong, L.L., Gilroy, E.J., Hirsch, R.M., and 

Wells, D.K., 1989, Estimating constituent loads: Water 

Resources Research, v. 25, no. 5, p. 937–942.

Davis, B.E., 2005, A guide to the proper selection and use of 

federally approved sediment and water-quality samplers: 

Vicksburg, Miss., U.S. Geological Survey Open File Report 

2005–1087, 20 p.

DeCicco, L., 2016, smwrGraphs package version 1.1.1: 

Accessed June 2017 at https://owi.usgs.gov/R.

Edwards, T.K., and Glysson, G.D., 1999, Field methods for 

measurement of fluvial sediment: Techniques of WaterResources Investigations of the United States Geological 

Survey, book 3, chap. C2, 89 p.

Federal Interagency Sedimentation Project, [n.d.], 

Operator’s manual for the US P-61-A1 point-integrating 

suspended-sediment sampler: Accessed July 6, 2017, 

at https://water.usgs.gov/fisp/docs/Instructions_US_P61-A1_030115.pdf.

Federal Interagency Sedimentation Project, 2011, Technical 

Committee Memorandum 2011.01, January 2011, US P-6 

point integrating suspended-sediment sampler: Accessed 

December 2017 at https://water.usgs.gov/fisp/docs/FISP_

Tech_Memo_US_P-6.pdf.

Gordon, J.D., Newland, C.A., and Gagliardi, S.T., 2000, 

Laboratory performance in the Sediment Laboratory 

Quality-Assurance Project, 1996–1998: U.S. Geological 

Survey Water Resources Investigations Report 99–4184, 

39 p.

Gray, J.R., Glysson, G.D., Turcios, L.M., and Schwarz, G.E., 

2000, Comparability of suspended-sediment concentration 

and total suspended solids data: U.S. Geological Survey 

Water Resources Investigations Report 00–4191, 14 p.

Gray, J.R., and Simões, F.J.M., 2008, Appendix D—

Estimating sediment discharge, in Garcia, M., ed., 

Sedimentation engineering: Processes, measurements, 

modeling, and practice: Reston, Va., American Society 

of Civil Engineers Manual 110, p. 1067–1088, accessed 

July 19, 2016, at http://water.usgs.gov/osw/techniques/

Gray_Simoes.pdf. 

Guo, Q., 2006, Correlation of total suspended solids 

(TSS) and suspended sediment concentration (SSC) test 

methods: Report prepared for New Jersey Department 

of Environmental Protection, November 2006, accessed 

May 17, 2016, at http://www.state.nj.us/dep/dsr/soils/

tss%20vs%20ssc%20test%20methods.pdf. 

Guy, H.P., 1969, Laboratory theory and methods for sediment 

analysis: Techniques of Water-Resources Investigations 

of the United States Geological Survey, book 5, chap. C1, 

58 p.

Heath, R.E., Brown, G.L., Little, C.D., Pratt, T.C., Ratcliff, 

J.J., Abraham, D.D., Perkey, E., Ganesh, N.B., Martin, K., 

and May, D.P., 2015, Old River Complex sedimentation 

investigation, Mississippi River Geomorphology and 

Potamology Program, Report 6: U.S. Army Engineer 

Research and Development Center Coastal and Hydraulics 

Laboratory, 149 p.

Joint Committee for Guides in Metrology, 2008, Evaluation 

of measurement data—Supplement 1 to the “Guide to the 

expression of uncertainty in measurement”—Propagation of 

distributions using a Monte Carlo method: Accessed July 7, 

2107, at https://www.bipm.org/utils/common/documents/

jcgm/JCGM_101_2008_E.pdf.
48 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Keown, M.P., Dardeau, E.A., and Kennedy, J.G., 1977, 

Inventory of sediment sample collection stations in the 

Mississippi River Basin: Technical Report M–77–1, U.S. 

Army Corps of Engineers Waterways Experiment Station, 

Vicksburg, Miss., 49 p.

Koltun, G.F., Eberle, M., Gray, J.R., and Glysson, G.D., 

2006, User’s manual for the Graphical Constituent Loading 

Analysis System (GCLAS): U.S. Geological Survey 

Techniques and Methods, 4–C1, 51 p.

Mossa, Joann, 1989, Hysteresis and nonlinearity of 

discharge-sediment relationships in the Atchafalaya and 

lower Mississippi Rivers: Sediment and the Environment 

(Proceedings of the Baltimore Symposium, May 1989), 

International Association of Hydrological Sciences (IAHS) 

Publication no. 184, p. 105–112.

Mueller, D.S., and Wagner, C.R., 2009, Measuring discharge 

with acoustic Doppler current profilers from a moving boat: 

U.S. Geological Survey Techniques and Methods 3–A22, 

72 p. 

Nguyen, I.H., Cox, A.N., Brown, J.L., Davinroy, R.D., Floyd, 

J., and Rivera, R., 2011, Mississippi River and Old River 

Control Complex sedimentation investigation and hydraulic 

response model study: U.S. Army Corps of Engineers St. 

Louis District Technical Report M53, 101 p.

Nordqvist, K., Galfi, H., Oserlund, H., Marsalek, J., 

Westerlund, C., and Viklander, M., 2014, Measuring solids 

concentrations in urban stormwater and snowmelt—A new 

operational procedure: Environmental Science: Processes 

and Impacts, v. 16, p. 2172–2183.

Norton, K.K., Olsen, L.D., Baumann, T.E., Simmons, L.B., 

Clark, A.P., Demcheck, D.K., and Johnson, M., 2019, 

Revised data and supporting information for seven sites 

located on the lower Mississippi and Atchafalaya Rivers 

sampled as part of a cooperative sediment program with 

the U.S. Army Corps of Engineers, October 1989 through 

February 2015: U.S. Geological Survey data release, 

https://doi.org/10.5066/F7K936GW.

Porterfield, G., 1972, Computations of fluvial-sediment 

discharge: U.S. Geological Survey Techniques of Water 

Resources Investigations, book 3, chap. C3, 66 p.

R Core Team, 2015, R: A language and environment for 

statistical computing: Vienna, Austria, https://R-project.org.

Thorne, C., Harmar, O., Watson, C., Clifford, N., Biedenharn, 

D., and Measures, M., 2008, Current and historical sediment 

loads in the lower Mississippi River: London, England, U.S. 

Army European Research Office, 146 p.

U.S. Army Corps of Engineers, 2017, Rivergages.com—Water 

levels of rivers and lakes: Accessed March 2017 at http://

rivergages.mvr.usace.army.mil/WaterControl/new/layout.

cfm#.

U.S. Geological Survey, 1993, Recommendations for use of 

retransformation methods in regression models used to 

estimate sediment loads (“the bias correction problem”): 

U.S. Geological Survey, Office of Surface Water Technical 

Memorandum 93.08, issued December 31, 1992, accessed 

July 19, 2016, at https://water.usgs.gov/admin/memo/SW/

sw93.08.html.

U.S. Geological Survey, 2013, Guidelines for FISP bag 

sampler intake efficiency tests and operational velocities: 

U.S. Geological Survey, Office of Surface Water Technical 

Memorandum 2013.02, issued June 13, 2013, accessed 

July 7, 2017, at https://water.usgs.gov/admin/memo/SW/

sw13.03.pdf.

U.S. Geological Survey, 2016, Water Mission Area policy on 

accepting furnished records: U.S. Geological Survey, Office 

of Surface Water Technical Memorandum 2016.04, issued 

July 7, 2016, accessed July 7, 2017, at https://water.usgs.

gov/admin/memo/SW/sw16.04.pdf.

U.S. Geological Survey, 2017, Sediment Laboratory Quality 

Assurance Project study results: U.S. Geological Survey 

Quality Systems Branch, accessed July 7, 2017, at https://

bqs.usgs.gov/slqa/frontpage_study_results.htm.

U.S. Geological Survey, 2018, USGS water data for the 

Nation: U.S. Geological Survey National Water Information 

System database, accessed November 2016 at https://doi.

org/10.5066/F7P55KJN.

U.S. Subcommittee on Sedimentation, Inter-agency Committee 

on Water Resources, 1943, A study of new methods for 

size analysis of suspended sediment samples—A study of 

methods used in measurement and analysis of sediment 

loads in streams: Report 7, 100 p.

U.S. Subcommittee on Sedimentation, Inter-agency Committee 

on Water Resources, 1963, Determination of fluvial sediment 

discharge—A study of methods used in measurement and 

analysis of sediment loads in streams: Report 14, 151 p.
Appendix 1 49

Appendix 1.

U.S. Army Corps of Engineers (USACE) FORTRAN source code for modules used to process 

laboratory results and compute suspended-sediment load for a cooperative program between 

the U.S. Geological Survey and the USACE in the lower Mississippi-Atchafalaya River Basin 

from 1973 to February 2015

Appendix 1 51

 INCLUDE 'FMENUS.INC'

 INCLUDE 'FGRAPH.FI'

C **** interface to call system services routine ****

 INTERFACE TO SUBROUTINE system[C](STRING)

 CHARACTER*1 STRING[REFERENCE]

 END

C==========================================================================

C 

C PROGRAM HH007

C -------------

C

C LABORATORY SUSPENDED SEDIMENT ANALYSIS PROGRAM 

C WRITTEN FOR H&H BRANCH

C *************************************************************

C

C WRITTEN BY J. P. CHIRIELEISON JR.

C AUGUST, 1974

C

C DOCUMANTATION ON FILE ADP, U.S. ARMY CORPS OF ENGINEERS,NOD.

C WRITTEN FOR HONEYWELL 635 COMPUTER LOCATED AT WES, VICKSBURG,MISS.

C

C

C REVISED JUNE, 1975 BY T. J. DUFRENE JR.

C LINES 6128-6131 ADDED

C

C

C REVIESED JUNE, 1976 BY T. J. DUFRENE JR.

C PROGRAM CHANGED TO ACCOMADATE BW DATA NOT AVAILABLE

C

C

C REVIESED JULY, 1976 BY T. J. DUFRENE JR.

C PROGRAM CHANGED SO THAT OUTPUT CONTAINS SUSPENDED SEDIMENT % FINER

C THAN, BED MATERIAL, LOAD AND CONCENTRATION IN 'HEIS' FORMAT.C

C

C REVISED FEBRUARY 1978 BY T. J. DUFRENE JR.

C PROGRAM CHANGED TO WRITE BED MATERIAL DATA IN THE

C BED MATERIAL FORMAT.

C

C OPTIONS FOR SELECTIVE PRINT OUT ADDED MAY 1978.

C ***************************************************************

C

C CONVERTED TO HARRIS 800 BY V. J. LAW JANUARY 1988

C CHANGED LFN ASSIGNMENTS BY ADDING 10

C

C ***************************************************************

C

C CONVERTED TO THE PC WITH MENUS BY: DON RAWSON

C SOURCE: HH007.FOR

C ENGID: HH007

C COMPLETED: 2/19/91

C
52 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C

C FC 1 = FIELD DATA FC 2 = CROSS SECTION DATA

C FC 3 = OUTPUT FC 4 = HEIS TAPE OUTPUT

C FC 5 = BED MATERIAL OUTPUT FC 10 = CHOICE FILE

C FC 11 = FIELD DATA FC 12 = CROSS SECTION DATA

C FC 13 = OUTPUT FC 14 = HEIS TAPE OUTPUT

C FC 15 = BED MATERIAL OUTPUT FC 20 = CHOICE FILE

C FC 30 = CRT

C TEST = '*'

C RECT1 = 'N' NO HEIS OR BED DATA WRITTEN

C ADP = ' NO' FC 3 PRINT OUT SURPRESSED

C IPAGES(1)=1 PAGE 1 TURNED OFF

C IPAGES(2)=1 PAGE 2 TURNED OFF

C IPAGES(3)=1 PAGE 3 TURNED OFF

C INPUT IN CHOICE FILE AS *A NO111

C **********************************************************

C

C

C MAIN

C ----

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER TITLE*50, PNAME*50

 INTEGER*1 getmouse,dummy

 INTEGER*2 mice

 TITLE='LABORATORY SUSPENDED SEDIMENT ANALYSIS PROGRAM'C

 PNAME='ENG. ID: HH007 - Version 1.0 - 16 AUG 1990'C

 dummy=getmouse(-2,mice,mice)

 CALL PTITLE(TITLE,PNAME)

 CALL mvprint(22, 3, 15,'STATUS: 'C)

 CALL GETDEFAULTS('LOAD')

 CALL DPROJECT

 CALL DOPTIONS

 CALL MENU

 CALL clearscreen ( $GCLEARSCREEN )

 STOP ' PROGRAM HH007 TERMINATED NORMALLY'

 END

C=========================================================================

 SUBROUTINE START(ERROR,MSG)

C -----------------------

C

C SUBROUTINE STARTS COMPUTATIONS

C

 INCLUDE 'FMENUS.REC'
Appendix 1 53

 DIMENSION NFS(10,8),DISRP(10),DESTA(10),DESAM(10,8),NPV(10)

 DIMENSION DISHV(10),DEPHH(10,8),HDIST(100),DEPXS(100)

 DIMENSION VEL(100)

 DIMENSION DEPHV(10),HLL(10),HLR(10),AREA(10,8),V(10,8)

 & ,PPMR(10,8),PPMT(10,8),PPMP(10,8),KB(119),I0(30),

 & TQSVR(8),TQSVP(8),TQSVT(8),MO(11),TQSHR(8),TQSHP(8),

 & TQSHT(8),BWW(10),BMP(18),PER(10),GSA(5,10,8),AGSA(5),WGSA(5)

 & ,NGS(20),PP120(10,8),TQ120(8)

 DIMENSION IBMP2(18), IPAGES(3)

 CHARACTER*5 IDATTY(36)

 CHARACTER*1 I0,KB

 CHARACTER*8 FILL, AIADP*5, AYR*2, AMO*2, ADA*2

 CHARACTER*3 FN0,FN1,FN2, IDOBS*5, IDESAM*5, ATC*7, AGAGE*6

 CHARACTER*6 TYSR,TPSS

 CHARACTER*74 TITLE, RECT*1, RECT1*1, ADP*3, TEST*1, AADP*5, EST*1

 CHARACTER*110 REC

 CHARACTER ATO*4

 CHARACTER AIID*7, ADESTA*5

 CHARACTER * 12 CDISH

 CHARACTER*30 MESS

 CHARACTER*60 FILE(25), PROJECT, DIRECTORY, MSG

 INTEGER XCORD,YCORD,JJJ

 INTEGER*4 IPDISH,ITQSR,ITQSP,ITQST,IWAPPMR,IWAPPMP,IWAPPMT

 LOGICAL ERROR

 COMMON /OPTIONS/ TEST,RECT1,ADP,IPAGES,RECT

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL FOPEN(ERROR,MSG)

 IF(ERROR)THEN

 RETURN 

 ENDIF

 

 ERROR = .FALSE.

 JJJ=1

 IDATTY(1)='80217'

 IDATTY(2)='80216'

 IDATTY(3)='80215'

 IDATTY(4)='80214'

 IDATTY(5)='80213'

 IDATTY(6)='80179'

 IDATTY(7)='80169'

 IDATTY(8)='80177'

 IDATTY(9)='80168'

 IDATTY(10)='80167'

 IDATTY(11)='80239'

 IDATTY(12)='80166'

 IDATTY(13)='80218'

 IDATTY(14)='80165'

 IDATTY(15)='80219'

 IDATTY(16)='80224'

 IDATTY(17)='80164'

 IDATTY(18)='70335'
54 Revisions to Suspended-Sediment Concentration, Mississippi-Atchafalaya River Basin, October 1989 to February 2015

 IDATTY(19)='70334'

 IDATTY(20)='70333'

 IDATTY(21)='70332'

 IDATTY(22)='70331'

 IDATTY(23)='70341'

 IDATTY(24)='70340'

 IDATTY(25)='70339'

 IDATTY(26)='70338'

 IDATTY(27)='80154'

 IDATTY(28)='80155'

 IDATTY(29)='80220'

 IDATTY(30)='80221'

 IDATTY(31)='80222'

 IDATTY(32)='80223'

 IDATTY(33)='00055'

 IDATTY(34)='00061'

 IDATTY(35)='00010'

 IDATTY(36)='00065'

 DATA KB,I0/119*' ','A','B','C','D','E',

 & 'F','G','H','I','J','K','L','M','N','O','P','Q','R','S',

 & 'T','U','V','W','X','Y','Z','#','*','.','-'/

 XCORD = 10 

 YCORD = 80

 NWRITE=0

 FN0=' '

 FN1='010'

 FN2='011'

 IDOBS='99995'

 FILL=' '

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22, 12, 15,'PROCESSING [ ]'C)

C

 WRITE(30,16)

 16 FORMAT('STATION DATE CONCENTRATION (P.P.M.)',16X,

 & 'LOAD (TONS/DAY)',12X,'DISCHARGE')

 

C CALL PTEXT(10,80,REC)

C YCORD=YCORD+15

C IF(YCORD.GE.340)YCORD=110

 WRITE(30,811)

811 FORMAT(' CODE MO/DA/YR',2(4X,'COARSE FINE',4X,

 &'TOTAL',5X),' PDISH. QBA')

C CALL PTEXT(10,95,REC)

C YCORD=YCORD+30

C IF(YCORD.GE.340)YCORD=110

 12 FORMAT('1')

 11 FORMAT(/)
Appendix 1 55

C IPAGES(1)=0

C IPAGES(2)=0

C IPAGES(3)=0

C

C ******************************************

C READING CHOICE FILE

C ******************************************

C

 IF(TEST.EQ.'*')GO TO 29

 29 RECT=RECT1

 IF(ADP.EQ.' NO') NWRITE=1

C

C **************************************

C READING 'A' CARD

C **************************************

C

 13 READ(11,2,END=999,ERR=800)AADP,TITLE

 2 FORMAT(A5,A74)

 READ(AADP,23)IADP

 23 FORMAT(I5)

C

 CALL INITAL (DISRP,DESTA,NPV,DISHV,HLL,HLR,BWW,PER,DEPHV,MO,NFS,

 & DESAM,DEPHH,AREA,V,PPMR,PPMP,PPMT,TQSVR,TQSVP,

 & TQSVT,TQSHR,TQSHP,TQSHT,GSA,WGSA,AGSA,HDIST,DEPXS,

 & VEL,BMP)

 IF(NWRITE.GT.0)GO TO 40

 WRITE(13,3)TITLE

 3 FORMAT('1',46X,'U.S. ARMY ENGINEER DISTRICT'/45X,'NEW ORLEANS',

 & ' CORPS OF ENGINEERS'//45X,'SUSPENDED SEDIMENT OBSERVATION',

 & /23X,A74//25X,'GAGE',58X,'WATER'/2X,'ADPS DATE',6X,

 & 'READING TIME',9X,2('TYPE '),' # OF',6X,

 & 'TEMPERATURE DEPTH DISCHARGE'/' CODE MO-DA-YR',6X,

 & 'FEET FROM TO SAMPLER SAMPLES VERTICALS',

 & 5X,'(DEG C) FEET C.F.S.')

 40 CONTINUE

C

C ***********************************************

C READING 'B' CARD

C ***********************************************

 READ(11,5,ERR=801)IDA,IMO,IYR,AGAGE,IFR,ITO,TYSR,TPSS,NVERT,ATC,

 & EST,DTCF,CDISH

 DO 77705 IK = 1, 12

 IF (CDISH(IK:IK) .EQ. ' ') THEN

 CDISH(IK:IK) = '0'

 ENDIF

77705 CONTINUE

 READ(CDISH,'(F12.0)')PDISH

 CALL CODET(ITO,ATO)

 5 FORMAT(3I2,A6,I6,I4,1X,2A6,I6,5X,A7,A1,F6.1,A12)

 READ(ATC,33)ITC

 33 FORMAT(I7)

 TC=ITC
56 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 TC=TC/10.

 ITC=ITC*1000

 READ(AGAGE,34)IGAGE

 34 FORMAT(I6)

 GAGE=IGAGE

 GAGE=GAGE/10.

 IGAGE=IGAGE*1000

 MDYF=IMO*10000+IDA*100+IYR

 IF(NWRITE.GT.0)GO TO 41

 WRITE(13,4)AADP,IMO,IDA,IYR,GAGE,IFR,ITO,TYSR,TPSS,NVERT,

 & TC,DTCF,PDISH

 4 FORMAT(1X,A5,I7,2('/',I2),F10.1,I10,I5,1X,2(4X,A6),10X,

 & I2,F14.1,F12.1,F14.0//)

 41 IBAD=0

 TOTBWW=0.

C

C ***********************************************

C READING 'C' CARD

C ************************************************

C

 READ(11,6,ERR=802)(BWW(I),I=1,10)

 6 FORMAT(17X,10F6.0)

C DO LOOP 30 GETS THE TOTAL WT. OF BOT. WITHDRAWAL SAMPLES AND

C DETERMINES IF THEY ARE DECREASING VALUES, IF THEY ARE NOT

C 'IBAD' IS SET = 4 AND NOTED ON THE OUTPUT.

 DO 30 I=1,10

 IF(I-10)22,30,30

 22 IP=I+1

 IF(BWW(I)-BWW(IP))25,30,30

 25 IBAD=4

 30 TOTBWW=TOTBWW+BWW(I)

C 'IBAD' IS SET = -4 IF BOTTOM WITHDRAWAL ANALYSIS WAS NOT TAKEN.

 IF(BWW(10))81,81,82

 81 IBAD=-4

 82 CONTINUE

C

C

C ***********************************************

C READING 'D' CARD

C ***********************************************

C

 READ(11,7,ERR=803)WC,SSC,TOVO,TCL

 7 FORMAT(12X,F6.0,12X,2(11X,F6.0),F16.1)

C

C ************************************************

C READING 'E' CARD

C ************************************************

C

 READ(11,8,ERR=804)(BMP(I),I=1,18)

 8 FORMAT(7X,18F4.1)

 IF(IBAD)70,72,72

 70 DO 71 I=1,9

 71 PER(I)=0.

 GO TO 73
Appendix 1 57

 72 CONTINUE

C --------------

 CALL ODEN(BWW,TOVO,WC,SSC,TCL,PER)

C --------------

 73 CONTINUE

 TOTWS=0.

 TOT230=0.

 TOTHF=0.

 NS=1

 NV=1

C

C ***********************************************

C READING 'F' CARD

C ***********************************************

C

 80 READ(11,9,ERR=805)NFS(NV,NS),SANDW,US18,US35,US60,US120,US230,

 & HFINE,TVOL,DISRP(NV),DESTA(NV),DESAM(NV,NS),KOD2,KOD3

 9 FORMAT(I4,13X,F5.0,4F4.0,F5.0,14X,F5.0,2F4.0,F3.0,F4.1,1X,2I1)

 N18=US18+.001

 UN18=N18

 IF(US18.GT.UN18)US18=US18*10000.

 N35=US35+.001

 UN35=N35

 IF(US35.GT.UN35)US35=US35*10000.

 N60=US60+.001

 UN60=N60

 IF(US60.GT.UN60)US60=US60*10000.

 N120=US120+.001

 UN120=N120

 IF(US120.GT.UN120)US120=US120*10000.

C FIND THE CONCENTRATION IN P.P.M.(RETAINED PASSED & TOTAL) OF

C EACH SAMPLE

 PPMR(NV,NS)=100.*US230/TVOL

 PP120(NV,NS)=100.*US120/TVOL

 PPMT(NV,NS)=100.*(SANDW+2.*HFINE)/TVOL

 PPMP(NV,NS)=PPMT(NV,NS)-PPMR(NV,NS)

C ACCUMULATE THE WT. OF WET SAND AND DRY SAND RETAINED ON THE

C U.S. 230 SIEVE AND THE ACCUMULATED WT. OF 1/2 FINES.

 TOTWS=TOTWS+SANDW

 TOT230=TOT230+US230

 TOTHF=TOTHF+HFINE

 T=SANDW+2.*HFINE

C FIND THE GRAIN SIZE % FINER OF EACH SAMPLE FOR THE

C 1.,.5,.25,.125 & .0625 M.M. SIZES

 GSA(1,NV,NS)=100.*(T-US18)/T

 GSA(2,NV,NS)=100.*(T-US35)/T

 GSA(3,NV,NS)=100.*(T-US60)/T

 GSA(4,NV,NS)=100.*(T-US120)/T

 GSA(5,NV,NS)=100.*(T-US230)/T

 IF(KOD3-1)100,130,100

 100 IF(KOD2-1)120,110,120

 110 NPV(NV)=NS

 NS=1

 NV=NV+1
58 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, October 1989 to February 2015

 GO TO 80

 120 NS=NS+1

 GO TO 80

C FROM HERE TO STATEMENT 510 COMPUTES SUB-AREAS REPRESENTATIVE

C OF EACH SAMPLE TAKEN IN THE CROSS SECTION

 130 NVM=NV-1

 NVP=NV+1

 NPV(NV)=NS

C COMPUTE DISTANCES HALFWAY BETWEEN VERTICALS

 DO 150 I=1,NVM

 IP=I+1

 150 DISHV(I)=(DISRP(I)+DISRP(IP))/2.

C COMPUTE DEPTHS HALFWAY BETWEEN HORIZONTALS

 DO 160 I=1,NV

 NPVM=NPV(I)-1

 IF(NPVM)157,157,155

 155 DO 156 J=1,NPVM

 JP=J+1

 156 DEPHH(I,J)=(DESAM(I,JP)+DESAM(I,J))/2.

 157 CONTINUE

 160 CONTINUE

 NOXS=3

C READ IN HORIZ. DIST., X-SEC & 60% VERTICAL VELOCITIES

 NVV=0

 165 NVV=NVV+1

C

C ************************************************

C READING 'G' CARD

C ************************************************

C

C IF ITYPE=3 THIS MEANS A REG. X-SEC CARD; IF ITYPE=4 THIS MEANS

C VEL. READ IN AS REV.(IN HUNDREDS)

 164 READ(12,167,ERR=807)ITYPE,LOC,MDYX,IFNL,ICNL,IFNG,ICNG,

 & HDIST(NVV),IDEPP,REV,TIME,IVFA,IACO

 IF(JJJ.EQ.1)THEN

 JJJ=2

 call mvputch(22 ,24, 4, 179)

 ELSEIF(JJJ.EQ.2)THEN

 JJJ=3

 call mvputch(22 ,24, 4, 45)

 ELSEIF(JJJ.EQ.3)THEN

 JJJ=4

 call mvputch(22 ,24, 4, 92)

 ELSEIF(JJJ.EQ.4)THEN

 JJJ=1

 call mvputch(22 ,24, 4, 47)

 ENDIF

 167 FORMAT(I1,I5,I6,18X,4I4,6X,F4.0,I4,F4.0,F3.0,I3,I4)

 IF(ITYPE.EQ.9)NOXS=2

 IF(NVV.GT.1)GO TO 162

 IF(MDYX.NE.MDYF)GO TO 161

 IF(LOC.NE.IADP)GO TO 161
Appendix 1 59

 GO TO 162

 161 WRITE(13,171)

 171 FORMAT('******* FIELD SEDIMENT DATA DOESN''T AGREE WITH THE',

 & ' CROSS SECTION & VEL. DATA IN DATE AND/OR LOCATION *******')

 WRITE(30,171)

 CALL mvprint(22 , 12, 14,'FIELD SEDIMENT DATA DOESN''T AGREE'C)

 RETURN

 162 DEPXS(NVV)=IDEPP

 DEPXS(NVV)=DEPXS(NVV)/10.

 FNL=IFNL

 FNL=FNL/1000.

 CNL=ICNL

 CNL=CNL/1000.

 FNG=IFNG

 FNG=FNG/1000.

 CNG=ICNG

 CNG=CNG/1000.

 VFA=IVFA

 VFA=VFA/100.

 ACO=IACO

 ACO=ACO/1000.

 IF(ITYPE-3)166,163,159

 159 VEL(NVV)=REV/100.

 GO TO 165

 163 RPS=REV/TIME

 IF(RPS-1.)168,168,169

 168 VEL(NVV)=VFA*ACO*(RPS*FNL+CNL)

 GO TO 165

 169 VEL(NVV)=VFA*ACO*(RPS*FNG+CNG)

 GO TO 165

 166 NVV=NVV-1

 KV=1

 DO 175 I=1,NVV

 IF(DISHV(KV)-HDIST(I))170,175,175

 170 IM=I-1

 DEPHV(KV)=(DEPXS(I)-DEPXS(IM))*(DISHV(KV)-HDIST(IM))

 DEPHV(KV)=DEPXS(IM)+DEPHV(KV)/(HDIST(I)-HDIST(IM))

 KV=KV+1

 IF(KV-NVM)175,175,176

 175 CONTINUE

C *******************************

C COMPUTE LENGTHS OF HORIZONTALS ON LEFT, THEN ON RIGHT

C *******************************

 176 DO 183 I=1,NVV

 IF(HDIST(I)-DISHV(1))183,184,184

 183 CONTINUE

 184 NVVD=I-1

 NVVM=NVV-1

 NPVM=NPV(1)-1

 NXL=1

 IF(NPVM)210,210,177

 177 DO 200 I=1,NPVM
60 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 DO 190 J=1,NVVD

 JP=J+1

 IF(DEPHH(1,I)-DEPXS(J))190,185,180

 180 IF(DEPHH(1,I)-DEPXS(JP))185,190,190

 185 HLL(I)=DISHV(1)-HDIST(J)-(HDIST(JP)-HDIST(J))*

 & (DEPHH(1,I)-DEPXS(J))/(DEPXS(JP)-DEPXS(J))

 NXL=JP

 190 CONTINUE

 200 CONTINUE

 210 NPVM=NPV(NV)-1

 J=NVV+1

 DO 187 I=1,NVV

 J=J-1

 IF(HDIST(J)-DISHV(NVM))188,188,187

 187 CONTINUE

 188 NVVD=I-1

 NXR=NVV

 IF(NPVM)241,241,215

 215 DO 240 I=1,NPVM

 KD=NVV+1

 DO 230 J=1,NVVD

 KD=KD-1

 KDM=KD-1

 IF(DEPHH(NV,I)-DEPXS(KD))230,225,220

 220 IF(DEPHH(NV,I)-DEPXS(KDM))225,230,230

 225 HLR(I)=HDIST(KD)-DISHV(NVM)-(HDIST(KD)-HDIST(KDM))*

 & (DEPHH(NV,I)-DEPXS(KD))/(DEPXS(KDM)-DEPXS(KD))

 NXR=KDM

 230 CONTINUE

 240 CONTINUE

C ******************************

C COMPUTE AREAS ON LEFT SIDE

C ******************************

 241 TDP=0.

 HLT=HLL(1)

 THD=DISHV(1)-HDIST(1)

 NVVD=NVV/2

 SA=0.

 DO 260 I=2,NVVD

 IM=I-1

 IF(DEPXS(I)-DEPXS(IM))248,242,248

 242 DEPXS(I)=DEPXS(I)+.0000001

 248 IF(HDIST(I)-DISHV(1)+HLL(1))250,270,270

 250 SA=(DISHV(1)-HDIST(I)+THD)/2.*(DEPXS(I)-TDP)+SA

 TDP=DEPXS(I)

 THD=DISHV(1)-HDIST(I)

 260 CONTINUE

 270 IF(DISHV(1)-HDIST(2)-HLL(1))275,275,274

 274 HLT=DISHV(1)-HDIST(2)

 275 AREA(1,1)=(HLL(1)+THD)/2.*(DEPHH(1,1)-TDP)+SA+DEPXS(1)/2.*

 & (DISHV(1)-HDIST(1)-HLT)

 TDP=DEPHH(1,1)

 THD=HLL(1)

 NPVM=NPV(1)-2
Appendix 1 61

 IF(NPVM)360,360,277

 277 DO 350 I=1,NPVM

 IP=I+1

 SA=0.

 DO 320 J=2,NVVD

 JM=J-1

 IF(DEPXS(J)-DEPXS(JM))290,280,290

 280 DEPXS(J)=DEPXS(J)+.0000001

 290 IF(HDIST(J)-DISHV(1)+HLL(I))320,320,300

 300 IF(HDIST(J)-DISHV(1)+HLL(IP))310,330,330

 310 SA=SA+(DISHV(1)-HDIST(J)+THD)/2.*(DEPXS(J)-TDP)

 THD=DISHV(1)-HDIST(J)

 TDP=DEPXS(J)

 320 CONTINUE

 330 AREA(1,IP)=SA+(HLL(IP)+THD)/2.*(DEPHH(1,IP)-TDP)

 TDP=DEPHH(1,IP)

 THD=HLL(IP)

 350 CONTINUE

C ******************************

C COMPUTE AREAS ON RIGHT SIDE

C ******************************

 360 TDP=0.

 HRT=HLR(1)

 THD=HDIST(NVV)-DISHV(NVM)

 SA=0.

 KD=NVV

 DO 390 I=2,NVVD

 KD=KD-1

 KDP=KD+1

 IF(DEPXS(KDP)-DEPXS(KD))378,372,378

 372 DEPXS(KD)=DEPXS(KD)+.0000001

 378 IF(HLR(1)+DISHV(NVM)-HDIST(KD))380,400,400

 380 SA=(HDIST(KD)-DISHV(NVM)+THD)/2.*(DEPXS(KD)-TDP)+SA

 TDP=DEPXS(KD)

 THD=HDIST(KD)-DISHV(NVM)

 390 CONTINUE

 400 IF(HDIST(NVVM)-DISHV(NVM)-HLR(1))395,395,394

 394 HRT=HDIST(NVVM)-DISHV(NVM)

 395 AREA(NV,1)=(HLR(1)+THD)/2.*(DEPHH(NV,1)-TDP)+SA+

 & DEPXS(NVV)/2.*(HDIST(NVV)-DISHV(NVM)-HRT)

 TDP=DEPHH(NV,1)

 THD=HLR(1)

 NPVM=NPV(NV)-2

 DO 450 I=1,NPVM

 IP=I+1

 SA=0.

 KD=NVV

 DO 430 J=2,NVVD

 KD=KD-1

 KDP=KD+1

 IF(DEPXS(KDP)-DEPXS(KD))409,401,409

 401 DEPXS(KD)=DEPXS(KD)+.0000001

 409 IF(HLR(I)+DISHV(NVM)-HDIST(KD))430,430,410

 410 IF(HLR(IP)+DISHV(NVM)-HDIST(KD))420,440,440
62 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 420 SA=SA+(HDIST(KD)-DISHV(NVM)+THD)/2.*(DEPXS(KD)-TDP)

 THD=HDIST(KD)-DISHV(NVM)

 TDP=DEPXS(KD)

 430 CONTINUE

 440 AREA(NV,IP)=SA+(HLR(IP)+THD)/2.*(DEPHH(NV,IP)-TDP)

 TDP=DEPHH(NV,IP)

 THD=HLR(IP)

 450 CONTINUE

 KNG=1

C **************************************************

C COMPUTE AREAS ALONG BOTTOM, INCLUDING LEFT AND RIGHT

C **************************************************

 N=NPV(1)-1

 SA=.5*(HLL(N)-(DISHV(1)-HDIST(NXL)))*(DEPXS(NXL)-DEPHH(1,N))

 IF(DEPXS(NXL).GE.DEPHH(1,N))GO TO 455

 NNP=N+1

 NGS(KNG)=NFS(1,NNP)

 KNG=KNG+1 

 455 K=1

 NXRM=NXR-1

 DO 500 I=NXL,NXRM

 IP=1+I

 IF(K-NV)460,470,470

 460 IF(DISHV(K)-HDIST(IP))480,480,470

 470 SA=SA+(HDIST(IP)-HDIST(I))*(DEPXS(IP)+DEPXS(I)-2.*DEPHH(K,N))/2.

 IF(DEPXS(I).GE.DEPHH(K,N))GO TO 500

 NNP=N+1

 NGS(KNG)=NFS(K,NNP)

 KNG=KNG+1

 GO TO 500

 480 NP=N+1

 AREA(K,NP)=SA+(DISHV(K)-HDIST(I))*(DEPXS(I)+DEPHV(K)-2.*

 & DEPHH(K,N))/2.

 IF(DEPXS(I).GE.DEPHH(K,N))GO TO 485

 NNP=N+1

 NGS(KNG)=NFS(K,NNP)

 KNG=KNG+1

 485 KP=K+1

 N=NPV(KP)-1

 SA=(HDIST(IP)-DISHV(K))*(DEPXS(IP)+DEPHV(K)-2.*DEPHH(KP,N))/2.

 IF(DEPXS(IP).GE.DEPHH(KP,N))GO TO 490

 NNP=N+1

 NGS(KNG)=NFS(KP,NNP)

 KNG=KNG+1

 490 K=KP

 500 CONTINUE

 N=NPV(NV)-1

 NP=N+1

 AREA(NV,NP)=SA+.5*(HLR(N)-(HDIST(NXR)-DISHV(NVM)))*

 & (DEPXS(NXR)-DEPHH(NV,N))

 IF(DEPXS(NXR).GE.DEPHH(NV,N))GO TO 501

 NNP=N+1

 NGS(KNG)=NFS(NV,NNP)

 KNG=KNG+1
Appendix 1 63

 501 CONTINUE

C **********************************

C COMPUTE AREAS IN MIDDLE SECTION(S)

C **********************************

 DO 510 I=2,NVM

 IM=I-1

 N=NPV(I)-1

 IF(N)510,510,502

 502 HD=DISHV(I)-DISHV(IM)

 AREA(I,1)=HD*DEPHH(I,1)

 IF(1-N)505,510,510

 505 DO 507 J=2,N

 JM=J-1

 507 AREA(I,J)=HD*(DEPHH(I,J)-DEPHH(I,JM))

 510 CONTINUE

 CALL CALVEL (NV,NVV,DISHV,HDIST,NPV,DEPHH,DEPXS,TC,V,VEL)

 IF(NWRITE.GT.0.OR.IPAGES(1).EQ.1)GO TO 42

 WRITE(13,615)

 615 FORMAT(1X,'FIELD DISTANCE TOTAL DEPTH PORTION OF',

 & ' CROSS SECTION US 120 SUSP. SED. CONCENTRATION',

 & ' GRAIN SIZE ',

 & 'ANALYSIS OF TOT.SUS.'/' SAMPLE FROM REF. STATION OF',

 & 7X,'REPRESENTED BY SAMPLE CONC US 230 SEIVE 0.0625'

 & ,' M.M.'

 & ,3X,'MATERIAL - CUMULATIVE % FINER'/' NUMBER POINT',5X,

 & 'DEPTH SAMPLE DISCHARGE VELOCITY AREA IN RETAINED',

 & ' PASSED TOTAL PARTICLE DIAMETER IN M.M.'/1X

 & ,6X,2(' FEET'),4X,'FEET',5X,'C.F.S. F.P.S. SQ.'

 & ,'FT. P.P.M. P.P.M.',2(' P.P.M.'),4X,'1.00 ',

 & '.500 .250 .125 .0625'/1X,127('-'))

 42 TPPMT=0.

 TPPMR=0.

 TPPMP=0.

 TPP120=0.

 NSAM=0

 AT=0.

 QT=0.

 DO 620 I=1,NV

 N=NPV(I)

 DO 620 J=1,N

 Q=AREA(I,J)*V(I,J)

 QT=QT+Q

 NSAM=NSAM+1

 TPPMT=TPPMT+PPMT(I,J)

 TPPMP=TPPMP+PPMP(I,J)

 TPPMR=TPPMR+PPMR(I,J)

 TPP120=TPP120+PP120(I,J)

 AT=AT+AREA(I,J)

 620 CONTINUE
64 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C *************************************************

C ADJUST ALL SUBVELOCITIES SO QT AGREES WITH PDISH

C *************************************************

 QBA=QT

 QF=PDISH/QT

 QT=0.

 IF(NOXS.EQ.2)QF=0.

 DO 613 I=1,NV

 N=NPV(I)

 DO 613 J=1,N

 V(I,J)=QF*V(I,J)

 Q=AREA(I,J)*V(I,J)

 613 QT=QT+Q

 614 XN=NSAM

 VAVG=QT/AT

 APPMT=TPPMT/XN

 APPMR=TPPMR/XN

 APPMP=TPPMP/XN

 APP120=TPP120/XN

 DO 660 I=1,NV

 N=NPV(I)

 DO 660 J=1,N

 DO 660 K=1,5

 AGSA(K)=AGSA(K)+GSA(K,I,J)

 660 WGSA(K)=WGSA(K)+GSA(K,I,J)*AREA(I,J)*V(I,J)/QT

 DO 659 K=1,5

 659 AGSA(K)=AGSA(K)/XN

 TQSR=0.

 TQP120=0.

 TQSP=0.

 TQST=0.

 DO 657 I=1,NV

 N=NPV(I)

 DO 657 J=1,N

 VA27=V(I,J)*AREA(I,J)*.0027

 TQSVR(I)=TQSVR(I)+PPMR(I,J)*VA27

 TQSVP(I)=TQSVP(I)+PPMP(I,J)*VA27

 TQSVT(I)=TQSVT(I)+PPMT(I,J)*VA27

 TQSHR(J)=TQSHR(J)+PPMR(I,J)*VA27

 TQSHP(J)=TQSHP(J)+PPMP(I,J)*VA27

 TQ120(J)=TQ120(J)+PP120(I,J)*VA27

 657 TQSHT(J)=TQSHT(J)+PPMT(I,J)*VA27

 DO 658 I=1,NV

 TQSR=TQSR+TQSVR(I)

 TQP120=TQP120+TQ120(I)

 TQSP=TQSP+TQSVP(I)

 658 TQST=TQST+TQSVT(I)

 WAPP120=TQP120/(.0027*QT)

 WAPPMR=TQSR/(.0027*QT)

 WAPPMP=TQSP/(.0027*QT)

 WAPPMT=TQST/(.0027*QT)

C ****************************************************************

C FIND THE MAX # OF PTS IN ANY ONE VERT. & IF ALL VERT. HAVE SAME #

C ****************************************************************
Appendix 1 65

 MPV=NPV(1)

 NSAME=0

 DO 640 I=2,NV

 IF(MPV-NPV(I))630,640,635

 630 MPV=NPV(I)

 635 NSAME=1

 640 CONTINUE

 IQ=0

 IR=0

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

C --------------

 CALL CODE(IADP,IYR,IMO,IDA,AIADP,AYR,AMO,ADA)

C --------------

 IF(ATC.EQ.' ')GO TO 31

 IF(EST.EQ.'E')GO TO 37

 IF(RECT.EQ.'N')GO TO 32

 CALL CODE2(DTCF,IDESAM)

 WRITE(14,791)RECT,AIADP,IDATTY(35),AYR,AMO,ADA,ATO,IDESAM,ITC,

 & FN0,FN0,FILL

 GO TO 32

 31 WRITE(30,1)' NO TEMPERATURE ON B CARD FOR FOLLOWING OBSERVATION'

C CALL PTEXT(10,340,REC)

 GO TO 32

 37 WRITE(30,1)' ESTIMATED TEMPERATURE ON B CARD FOR FOLLOWING OBSE

 $RVATION.'

C CALL PTEXT(10,340,REC)

 32 IF(AGAGE.EQ.' ')GO TO 35

 IF(RECT.EQ.'N')GO TO 36

 WRITE(14,791)RECT,AIADP,IDATTY(36),AYR,AMO,ADA,ATO,IDOBS,IGAGE,

 & FN0,FN0,FILL

C CALL PTEXT(XCORD,YCORD,REC)

C YCORD=YCORD+15

C IF(YCORD.GE.340)YCORD=110

 GO TO 36

 35 WRITE(30,1)' NO GAGE READING ON B CARD FOR FOLLOWING OBSERVATION'

C CALL PTEXT(10,340,REC)

 36 CONTINUE

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

 DO 633 I=1,NV

 N=NPV(I)

 DO 633 J=1,N

 ID=INT(DISRP(I))

 IF(NOXS.EQ.2)GO TO 616

 IQ=INT(AREA(I,J)*V(I,J))

 IR=INT(AREA(I,J))

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

 616 CALL CODE2(DESAM(I,J),IDESAM)

 IF(RECT.EQ.'N')GO TO 627

 CALL ROUND2(PPMT(I,J),IPPMT)
66 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 CALL ROUND2(PPMP(I,J),IPPMP)

 CALL ROUND2(PPMR(I,J),IPPMR)

 IID=ID*100

 CALL CODE7(IID,AIID)

 CALL CODE2(DESTA(I),ADESTA)

C

 WRITE(14,617)RECT,AIADP,IDATTY(27),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IPPMT,FN0,FN0,FILL

 WRITE(14,617)RECT,AIADP,IDATTY(31),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IPPMP,FN0,FN0,FILL

 WRITE(14,617)RECT,AIADP,IDATTY(29),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IPPMR,FN0,FN0,FILL

 617 FORMAT(A1,A5,3X,A6,3A2,A4,1X,A5,1X,A7,1X,A5,2X,I11,2A3,A8)

 DO 618 K=1,5

 CALL ROUND1(GSA(K,I,J),IGSA)

 KK=K+17

 618 WRITE(14,617)RECT,AIADP,IDATTY(KK),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IGSA,FN0,FN0,FILL

 IF(NOXS.EQ.2)GO TO 627

 IIQ=IQ*10000

 CALL ROUND2(V(I,J),IV)

 WRITE(14,617)RECT,AIADP,IDATTY(33),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IV,FN1,FN0,FILL

 WRITE(14,617)RECT,AIADP,IDATTY(34),AYR,AMO,ADA,ATO,IDESAM,AIID,

 & ADESTA,IIQ,FN1,FN0,FILL

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

C

 627 IF(NWRITE.GT.0.OR.IPAGES(1).EQ.1)GO TO 633

 WRITE(13,628)NFS(I,J),ID,DESTA(I),DESAM(I,J),IQ,V(I,J),

 & IR,PP120(I,J),PPMR(I,J),PPMP(I,J),PPMT(I,J),

 & (GSA(K,I,J),K=1,5)

 628 FORMAT(1X,I5,I10,F9.1,F8.1,I10,F9.2,I9,2F8.2,2F9.2,F9.1,4F6.1)

 633 CONTINUE

 619 IF(NOXS.EQ.2)GO TO 651

 IF(NWRITE.GT.0.OR.IPAGES(1).EQ.1)GO TO 43

 WRITE(13,429)APP120,APPMR,APPMP,APPMT,(AGSA(I),I=1,5),QT,AT,VAVG,

 & WAPP120,WAPPMR,WAPPMP,WAPPMT,(WGSA(J),J=1,5)

 429 FORMAT(1X,127('-')/3X,'STRAIGHT NUMERICAL AVERAGES',30X,F9.2,

 &F8.2,2F9.2,F9.1,4F6.1/3X,'TOTALS',21X,F14.0,F18.0/3X,'DISCHARGE',

 & ' WEIGHTED AVERAGES',F22.2,F17.2,F8.2,2F9.2,F9.1,4F6.1,/)

 43 IF(KNG.LE.1)GO TO 625

 GO TO 653

 651 IF(NWRITE.GT.0.OR.IPAGES(1).EQ.1)GO TO 432

 WRITE(13,428)APPMR,APPMP,APPMT,(AGSA(I),I=1,5)

 428 FORMAT(1X,119('-')/3X'STRAIGHT NUMERICAL AVERAGES ',29X,

 & 3F9.2,F9.1,4F6.1/////' AVERAGES HAVE NOT BEEN DISCHARGE',

 & ' WEIGHTED BECAUSE VELOCITY AND CROSS SECTION DATA WAS ',

 & 'NOT AVAILABLE.')

 IF(NV.GT.2)GO TO 432

 WRITE(13,431)

 431 FORMAT(/' OR LESS THAN THREE VERTICALS WERE TAKEN.')

 432 DO 427 I=1,5

 427 WGSA(I)=AGSA(I)

 TQSR=APPMR*PDISH*.0027
Appendix 1 67

 TQSP=APPMP*PDISH*.0027

 TQST=APPMT*PDISH*.0027

 WAPPMT=APPMT

 WAPPMR=APPMR

 WAPPMP=APPMP

 GO TO 701

 653 IF(NWRITE.GT.0.OR.IPAGES(1).EQ.1)WRITE(13,24)AIADP,IMO,IDA,IYR

 WRITE(13,624)

 624 FORMAT(////'******* THE FOLLOWING FIELD SAMPLE(S) SHOULD',

 & ' BE ELIMINATED AND THIS DATE RERUN. *******'//)

 KNG=KNG-1

 DO 623 I=1,KNG

 IF(I.EQ.1)GO TO 622

 IM=I-1

 IF(NGS(IM)-NGS(I))622,623,622

 622 WRITE(13,632)NGS(I)

 632 FORMAT(15X,I6)

 623 CONTINUE

 WRITE(13,621)

 621 FORMAT(/'******* THE PRESENCE OF THESE FIELD SAMPLE(S)',

 & ' HAS CAUSED A SMALL ERROR IN THE RESULTS DUE TO THE LOCATION',

 & '. *******')

 625 CONTINUE

 N=(NV*8-24)/2

 IF(N.LT.1)N=1

C

C *************************************************

C WRITING OUTPUT FOR PAGE 2

C **************************************************

 IF(NWRITE.GT.0.OR.IPAGES(2).EQ.1)GO TO 666

 IF(IPAGES(1).EQ.1)GO TO 634

 18 FORMAT(1H1)

 WRITE(13,18)

 WRITE(13,24)AIADP,IMO,IDA,IYR

 24 FORMAT(A5,I6,2('/',I2),96X,'PAGE 2')

 634 WRITE(13,629)(KB(I),I=1,N),I0(28),

 & I0(28),I0(28),I0(28),KB(1),

 & I0(3),I0(18),I0(15),I0(19),I0(19),KB(1),I0(19),I0(5),I0(3),

 & I0(20),I0(9),I0(15),I0(14),KB(1),I0(16),I0(18),I0(15),I0(6),

 & I0(9),I0(12),I0(5),KB(1),I0(28),I0(28),I0(28),I0(28)

 629 FORMAT(///119A1///)

 WRITE(13,626)

 626 FORMAT(//' CROSS SECTION LAYOUT OF FIELD SAMPLE NUMBERS'//

 & )

 WRITE(13,650)(KB(I),KB(I),KB(I),I0(22),I0(5),I0(18),

 & I0(20),I0(29),I=1,NV)

 650 FORMAT(1X,119A1)

 WRITE(13,631)(I0(27),I,I=1,NV)

 631 FORMAT(9(5X,A1,I2))

 N=NV*8

 WRITE(13,650)(I0(30),I=1,N)

 DO 652 I=1,MPV

 WRITE(13,655)(NFS(J,I),J=1,NV)

 655 FORMAT(10I8)
68 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 652 CONTINUE

 WRITE(13,650)(I0(30),I=1,N)

 WRITE(13,650)(KB(I),KB(I),KB(I),I0(20),I0(15),I0(20),I0(1),

 & I0(12),I=1,NV),KB(1),KB(1),I0(7),I0(18),I0(1),I0(14),I0(4),

 & KB(1),I0(20),I0(15),I0(20),I0(1),I0(12)

 666 DO 702 N=1,3

 IF(NWRITE.GT.0.OR.IPAGES(2).EQ.1)GO TO 670

 IF(N-2)661,662,663

 661 WRITE(13,674)

 674 FORMAT(///' LOADS IN THE FOLLOWING TABLES CORRESPOND'/

 & ' TO FIELD SAMPLE NUMBERS IN THE ABOVE TABLE'////

 & ' SAND FRACTION (MATERIAL COARSER THAN 0.0625 M.M) IN TONS',

 & '/DAY'//)

 GO TO 670

 662 WRITE(13,664)

 664 FORMAT(////' SILT-CLAY FRACTION (MATERIAL FINER THAN 0.0625',

 & ' M.M.) IN TONS/DAY'//)

 GO TO 670

 663 WRITE(13,665)

 665 FORMAT(////' TOTAL SUSPENDED SEDIMENT LOADS IN TONS/DAY'//)

C

 670 DO 689 I=1,MPV

 DO 675 J=1,NV

 IF(N-2)671,672,673

 671 X=PPMR(J,I)

 GO TO 675

 672 X=PPMP(J,I)

 GO TO 675

 673 X=PPMT(J,I)

 675 MO(J)=X*V(J,I)*AREA(J,I)*.0027

 IF(N-2)681,682,683

 681 MO(NVP)=TQSHR(I)

 GO TO 680

 682 MO(NVP)=TQSHP(I)

 GO TO 680

 683 MO(NVP)=TQSHT(I)

 680 IF(NSAME)685,684,685

 684 NSPN=NVP

 GO TO 690

 685 NSPN=NV

 690 IF(NWRITE.GT.0.OR.IPAGES(2).EQ.1)GO TO 689

 WRITE(13,655)(MO(K),K=1,NSPN)

 689 CONTINUE

 NV8=NV*8

 IF(NWRITE.GT.0.OR.IPAGES(2).EQ.1)GO TO 44

 WRITE(13,650)(I0(30),II=1,NV8)

 44 MO(NVP)=0

 DO 694 I=1,NV

 IF(N-2)691,692,693

 691 MO(I)=TQSVR(I)

 GO TO 694

 692 MO(I)=TQSVP(I)

 GO TO 694

 693 MO(I)=TQSVT(I)
Appendix 1 69

 694 CONTINUE

 IF(N-2)695,696,697

 695 MO(NVP)=TQSR

 GO TO 700

 696 MO(NVP)=TQSP

 GO TO 700

 697 MO(NVP)=TQST

 700 IF(NWRITE.GT.0.OR.IPAGES(2).EQ.1)GO TO 702

 WRITE(13,655)(MO(K),K=1,NVP)

 702 CONTINUE

 701 SDC=1.-(TOT230)/(TOTWS+TOTHF+TOTBWW+WC+SSC*TOVO/50.)

 DO 720 I=1,9

 720 PER(I)=PER(I)*SDC

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

 IF(RECT.EQ.'N')GO TO 721

 J=0

 DO 722 I=18,22

 J=J+1

 CALL ROUND1(WGSA(J),IWGSA)

 722 WRITE(14,791)RECT,AIADP,IDATTY(I),AYR,AMO,ADA,ATO,IDOBS,IWGSA,FN1,

 & FN2,FILL

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

C

C ****************************************************

C WRITING OUTPUT FOR PAGE 3

C ******************************************************

 721 IF(NWRITE.GT.0.OR.IPAGES(3).EQ.1)GO TO 739

 IF(IPAGES(1).EQ.1.AND.IPAGES(2).EQ.1)GO TO 723

 WRITE(13,18)

 WRITE(13,26)AIADP,IMO,IDA,IYR,NOXS

 26 FORMAT(A5,I6,2('/',I2),96X,'PAGE',I2)

 723 WRITE(13,740)(WGSA(I),I=1,5),(PER(J),J=2,9)

 740 FORMAT(//////3X,

 & 17('* '),'COMBINED SUSPENDED',

 & ' SEDIMENT GRAIN SIZE ANALYSIS',17(' *')///6X,'DIAMETER ',

 & 'IN M.M. 1.00 .500 .250 .125 .0625',6X,

 & '.0442 .0312 .0221 .0156 .0110 .0075 .0055 .0039',

 & /8X,'PERCENT FINER ',5F7.1,F11.1,7F7.1/23X,'.',33X,'.',

 & ' .',53X,'.'/24X,'.',31X,'. .',51X,'.'/25X,

 & '...MECHANICAL SIEVE ANALYSIS...',9X,12('.'),

 & 'BOTTOM WITHDRAWAL ANALYSIS',13('.')///)

 739 IF(IBAD)741,747,742

 741 IF(NWRITE.GT.0.OR.IPAGES(3).EQ.1)GO TO 745

 WRITE(13,744)

 744 FORMAT(1X,' NOTE: BOTTOM WITHDRAWAL DATA WAS NOT AVAILABLE',

 & ', THEREFORE THE ABOVE ANALYSIS'/9X,'FOR DIAMETERS FINER THAN',

 & ' 0.0625 MM SHOULD NOT BE TAKEN AS 0% FINER THAN'///)

 GO TO 745

 742 IF(NWRITE.GT.0.OR.IPAGES(3).EQ.1)GO TO 745

 WRITE(13,743)

 743 FORMAT(1X,' NOTE: DUE TO BAD LAB RESULTS FROM THE BOTTOM',

 & ' WITHDRAWAL METHOD, THE ABOVE ANALYSIS'/9X,'FOR DIAMETERS',

 & ' FINER THAN 0.0625 M.M. SHOULD NOT BE TAKEN TO BE VERY ',

 & 'ACCURATE'///)
70 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

 GO TO 745

 747 J=1

 IF(RECT.EQ.'N')GO TO 745

 DO 746 I=23,26

 J=J+2

 CALL ROUND1(PER(J),IPER)

 746 WRITE(14,791)RECT,AIADP,IDATTY(I),AYR,AMO,ADA,ATO,IDOBS,IPER,FN0,

 & FN2,FILL

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

 745 IBED=0

 IF(BMP(1))770,770,750

 750 IF(NWRITE.GT.0.OR.IPAGES(3).EQ.1)GO TO 761

 WRITE(13,760)(BMP(I),I=1,18)

 760 FORMAT(///2X,21('* '),'BED MATERIAL GRAIN SIZE ANALYSIS',

 & 21(' *')///' DIA. IN M.M. 25.4 19.1 12.7 9.52 4.76 ',

 & '3.36 2.00 1.41 1.00 .500 .350 .250 .177 .125 ',

 & '.088 .074 .062 PAN'/' % FINER ',18F6.1///)

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

 761 J=0

 IF(RECT.EQ.'N')GO TO 771

 DO 766 I=1,17

 J=J+1

 CALL ROUND1(BMP(J),IBMP)

 766 IBMP2(I)=IBMP/1000

 WRITE(15,792)I0(1),AIADP,AYR,AMO,ADA,(IBMP2(I),I=2,13)

 WRITE(15,792)I0(2),AIADP,AYR,AMO,ADA,(IBMP2(I),I=14,18)

 792 FORMAT(A1,'1',A5,9X,3A2,10X,12I4)

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

 GO TO 771

 770 IBED=10

 771 CONTINUE

 WRITE(30,772) IADP,IMO,IDA,IYR,WAPPMR,WAPPMP,WAPPMT,TQSR,

 & TQSP,TQST,PDISH,QBA

C CALL PTEXT(XCORD,YCORD,REC)

C YCORD=YCORD+15

C IF(YCORD.GE.340)YCORD=110

 772 FORMAT(I6,I5,2('/',I2),F10.2,2F9.2,6X,5F10.0)

 IF(NWRITE.GT.0.OR.IPAGES(3).EQ.1)GO TO 762

 WRITE(13,730)I0(3),I0(15),I0(1),I0(18),I0(19),I0(5),TQSR,

 & WAPPMR,KB(1),I0(6),I0(9),I0(14),I0(5),KB(1),TQSP,WAPPMP,

 & KB(1),I0(20),I0(15),I0(20),I0(1),I0(12),TQST,WAPPMT

 730 FORMAT(/////1X,23('* '),'SUSPENDED SEDIMENT SUMMARY',

 & 23(' *'),////38X,43('*')/38X,'*',10X,2(':',14X),' *'/

 & 38X,'* MATERIAL : LOAD : CONCENTRATION *'/38X,

 & '* TYPE : (TONS/DAY) : (P.P.M.) *'/38X,'*',

 & 10('-'),2(':',14('-')),'-*',3(/38X,'* ',6A1,2X,':',

 & F11.0,' :',F11.2,' *'/38X,'*',10X,2(':',14X),' *')/

 & 38X,43('*')//)

C \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/ \/

 762 CALL ROUND0(TQSR,ITQSR)

 CALL ROUND0(TQSP,ITQSP)
Appendix 1 71

 CALL ROUND0(TQST,ITQST)

 CALL ROUND2(WAPPMR,IWAPPMR)

 CALL ROUND2(WAPPMP,IWAPPMP)

 CALL ROUND2(WAPPMT,IWAPPMT)

 IBAD=ABS(IBAD)

 J=17-IBAD+IBED

 IF(RECT.EQ.'N')GO TO 13

 IF(PDISH)788,788,786

 786 CALL ROUND0(PDISH,IPDISH)

 WRITE(14,971)RECT,AIADP,IDATTY(34),AYR,AMO,ADA,ATO,IDOBS,IPDISH,

 & FN0,FN2,FILL

 WRITE(14,971)RECT,AIADP,IDATTY(30),AYR,AMO,ADA,ATO,IDOBS,ITQSR,

 & FN1,FN2,FILL

 WRITE(14,971)RECT,AIADP,IDATTY(32),AYR,AMO,ADA,ATO,IDOBS,ITQSP,

 & FN1,FN2,FILL

 WRITE(14,971)RECT,AIADP,IDATTY(28),AYR,AMO,ADA,ATO,IDOBS,ITQST,

 & FN1,FN2,FILL

 788 WRITE(14,791)RECT,AIADP,IDATTY(29),AYR,AMO,ADA,ATO,IDOBS,IWAPPMR,

 & FN1,FN2,FILL

 WRITE(14,791)RECT,AIADP,IDATTY(31),AYR,AMO,ADA,ATO,IDOBS,IWAPPMP,

 & FN1,FN2,FILL

 WRITE(14,791)RECT,AIADP,IDATTY(27),AYR,AMO,ADA,ATO,IDOBS,IWAPPMT,

 & FN1,FN2,FILL

 791 FORMAT(A1,A5,3X,A6,3A2,A4,1X,A5,16X,I11,2A3,A8)

C 

C MODIFIED FOR PC VERSION BY DON RAWSON 27 SEP 90

C IPDISH, ITQSR, ITQSP, ITQST RETURNS A VALUE OUT FO ROUNDO LARGER THEN

C INTEGER*4 WILL SUPPORT.

C

 971 FORMAT(A1,A5,3X,A6,3A2,A4,1X,A5,16X,I7,'0000',2A3,A8)

C /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

 GO TO 13

C

C _______________________________________________________________

C

 999 WRITE(30,1)' E N D O F J O B'

1 FORMAT(A110)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'END OF JOB'C)

 GO TO 998

 800 WRITE(30,1)'ERROR ON TITLE CARD(CARD # 1) OF FIELD DATA'

 WRITE(30,1)REC

 MSG = 'ERROR ON TITLE CARD(CARD # 1) OF FIELD DATA'C

 ERROR = .TRUE.

 GO TO 998

 801 WRITE(30,1)'ERROR ON DATE DISCHARGE CARD (CARD #2) OF FIELD DATA'

 MSG = 'ERROR ON DATE DISCHARGE CARD (CARD #2) OF FIELD DATA'C

 ERROR = .TRUE.

 GO TO 998

 802 WRITE(30,1)'ERROR ON BOT.WITH. CARD (CARD # 3) OF FIELD DATA'

 MSG = 'ERROR ON BOT.WITH. CARD (CARD # 3) OF FIELD DATA'C

 ERROR = .TRUE.

 GO TO 998
72 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 803 WRITE(30,1)'ERROR ON CARD # 4 OF FIELD DATA'

 MSG = 'ERROR ON CARD # 4 OF FIELD DATA'C 

 ERROR = .TRUE.

 GO TO 998

 804 WRITE(30,1)'ERROR ON BED MAT. CARD (CARD # 5) OF FIELD DATA'

 MSG='ERROR ON BED MAT. CARD (CARD # 5) OF FIELD DATA'C

 ERROR = .TRUE.

 GO TO 998

 805 WRITE(30,806) NV,NS

 806 FORMAT('ERROR ON SED CARD OF FIELD DATA-NV=',I2,'NS=',I2)

 MSG='ERROR ON SED CARD'C

 ERROR = .TRUE.

 GO TO 998

 807 WRITE(REC,808) NVV

 808 FORMAT('ERROR ON X-SECTION CARD #',I4)

 WRITE(30,1)REC

 MSG=REC//CHAR(0)

 ERROR = .TRUE.

 998 CONTINUE

 CLOSE(UNIT=11)

 CLOSE(UNIT=12)

 CLOSE(UNIT=20)

 CLOSE(UNIT=13)

 CLOSE(UNIT=14)

 CLOSE(UNIT=15)

 IF(.NOT.ERROR)THEN

 CALL clean(0, 22, 12, 22, 27)

 CALL mvprint(22, 12, -14,'SORTING...'C)

 WRITE(REC,444)FILE(5)

444 FORMAT('COPY ',A12,' SORT.HES > nul')

 CALL SYSTEM(REC//CHAR(0))

 CALL SYSTEM('\\SEDIMENT\\HEIS'C)

 WRITE(REC,445)FILE(5)(1:12)

445 FORMAT('COPY SORTED.SDF ',A12,' > nul')

 CALL SYSTEM(REC//CHAR(0))

 CALL SYSTEM('DEL SORTED.SDF 'C)

 CALL SYSTEM('DEL SORT.HES 'C)

 CALL clean(0, 22, 12, 22, 70)

 ENDIF

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE ODEN(BWW,TOVO,WC,SSC,TCL,PER)

C ----------------------------------------

C ABSOLUTE VISCOSITY OF WATER FOR TEMP. 1 THRU 35 DEGREES CENT.

 DIMENSION BWW(10),PER(9),AV(35),PD(9),SETT(10)

 AV(1)=.00001765

 AV(2)=.00001706

 AV(3)=.00001652
Appendix 1 73

 AV(4)=.00001598

 AV(5)=.00001549

 AV(6)=.00001502

 AV(7)=.00001457

 AV(8)=.00001413

 AV(9)=.00001373

 AV(10)=.00001333

 AV(11)=.00001296

 AV(12)=.00001261

 AV(13)=.00001226

 AV(14)=.00001194

 AV(15)=.00001163

 AV(16)=.00001133

 AV(17)=.00001104

 AV(18)=.00001077

 AV(19)=.00001050

 AV(20)=.00001025

 AV(21)=.00001000

 AV(22)=.00000977

 AV(23)=.00000954

 AV(24)=.00000932

 AV(25)=.00000911

 AV(26)=.00000891

 AV(27)=.00000871

 AV(28)=.00000853

 AV(29)=.00000834

 AV(30)=.00000816

 AV(31)=.00000799

 AV(32)=.00000783

 AV(33)=.00000767

 AV(34)=.00000752

 AV(35)=.00000737

C PARTICLE DIAMETER(IN MM) OF GRAIN SIZES TO BE ANALIZED

 PD(1)=.0625

 PD(2)=.0442

 PD(3)=.0312

 PD(4)=.0221

 PD(5)=.0156

 PD(6)=.0110

 PD(7)=.0078

 PD(8)=.0055

 PD(9)=.0039

C SETTLEING TIMES(IN MIN.) USED IN PLOTTING ODEN CURVE

 SETT(1)=.001

 SETT(2)=40./9.

 SETT(3)=80./8.

 SETT(4)=135./7.

 SETT(5)=250./6.

 SETT(6)=500./5.

 SETT(7)=660./4.

 SETT(8)=880./3.

 SETT(9)=1000./2.

 SETT(10)=1200.

C ADD SUSPENDED SOLIDS AND WASH CORRECTIONS TO B.W. SAMPLES
74 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 DO 30 I=1,10

 30 BWW(I)=BWW(I)+SSC*TOVO/500.+WC/10.

C GET CUMULATIVE WTS. IN REVERSE ORDER OF CORRECTED B.W. SAMPLES

 K=10

 DO 40 I=1,9

 K=K-1

 KP=K+1

 40 BWW(K)=BWW(K)+BWW(KP)

C GET SEDIMENT IN SUSPENSION BY MULT. BY DEPTH FACTOR

 XI=10.

 DO 50 I=2,10

 XI=XI-1.

 50 BWW(I)=BWW(I)*(10./XI)

C GET % IN SUSPENSION

 DO 60 I=2,10

 60 BWW(I)=100.*BWW(I)/BWW(1)

 BWW(1)=100.

C FIND ABSOLUTE VISCOSITY OF WATER FOR THE LAB TEMP.

 LTC=TCL+.01

 TTC=LTC

 LTCP=LTC+1

 ABVIS=AV(LTC)+(AV(LTCP)-AV(LTC))*(TCL-TTC)

 DO 200 I=1,9

 IP=I+1

C COMPUTE SETTLING VELOCITY OF PARTICLE DIA. 'I' BY STOKES LAW

 SETV=2./9.*(1.65/ABVIS)*(PD(I)/(2.*10.))**2

C COMPUTE SETTELING TIME TO SETTLE 100 CM. - IN MINUTES

 SETIME=100./(60.*SETV)

C TO APPROX. ODEN CURVE USE A PARABOLA FOR THE FIRST

C 3 POINTS AND A HYPERBOLA FOR THE REMAINING POINTS

 IF(I-3)135,135,65

 65 CONTINUE

C FIND THE 2 POINTS ON THE ODEN CURVE CLOSEST TO SETT(J)

 DO 70 J=2,10

 JM=J-1

 JP=J+1

 IF(SETIME-SETT(J))75,85,70

 70 CONTINUE

 GO TO 120

 75 IF(J-2)80,80,85

 80 T1=SETT(2)

 T2=SETT(3)

 P1=BWW(2)

 P2=BWW(3)

 GO TO 130

 85 T2=SETT(J)

 T1=SETT(JM)

 P2=BWW(J)

 P1=BWW(JM)

 GO TO 130

 120 T1=SETT(9)

 T2=SETT(10)

 P1=BWW(9)

 P2=BWW(10)
Appendix 1 75

 130 CONTINUE

C SOLVE 2 EQ. & 2 UNKNOWNS TO GET A HYPERBOLIC EQ. FOR THE 2 POINTS

 YO=(T1*P1-T2*P2)/(T1-T2)

 C=T1*P1-T1*YO

 Y=C/SETIME+YO

C TAKE DERIVITIVE AND GET SLOPE AT POINT SETIME

 DXDY=-C/(Y-YO)**2

 GO TO 195

 135 D1=ABS(SETIME-SETT(2))

 D2=ABS(SETIME-SETT(3))

 IF(D1-D2)136,137,137

 136 M=2

 GO TO 138

 137 M=3

 138 MM=M-1

 MP=M+1

 P1=BWW(MM)

 P2=BWW(M)

 P3=BWW(MP)

 T1=SETT(MM)

 T2=SETT(M)

 T3=SETT(MP)

C SOLVE 3 EQ. AND 3 UNKNOWNS FOR A PARABOLIC FIT FOR FIRST FEW PTS.

 A=((P2-P3)*(T1-T2)-(P1-P2)*(T2-T3))/

 & ((P2-P3)*(P1**2-P2**2)-(P1-P2)*(P2**2-P3**2))

 B=((T1-T2)-A*(P1**2-P2**2))/(P1-P2)

 C=T3-A*P3**2-B*P3

 YH=(-B+SQRT(B**2-4.*A*(C-SETIME)))/(2.*A)

 YL=(-B-SQRT(B**2-4.*A*(C-SETIME)))/(2.*A)

 D1=ABS(YH-BWW(M))

 D2=ABS(YL-BWW(M))

 IF(D1-D2)140,140,150

 140 Y=YH

 GO TO 160

 150 Y=YL

 160 CONTINUE

C TAKE DERIVITIVE AND GET SLOPE AT POINT SETIME

 DXDY=2.*A*Y+B

 195 PER(I)=Y-SETIME/DXDY

 200 CONTINUE

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE ROUND1(A,I)

C ----------------------

C

C

 INTEGER*4 I,II

 AA=A*10.+.5

 II=AA
76 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 I=II*1000.

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE ROUND0(A,I)

C ----------------------

C

C

 

 INTEGER*4 I,II,INT4

 AA=A+.5

 II=INT4(AA)

 I=II

C I=II*10000.

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE ROUND2(A,I)

C ----------------------

C

C

 INTEGER*4 I,II,INT4

 AA=A*100.+.5

 II=INT4(AA)

 I=II*100.

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE CODE(IADP,T1,T2,T3,AIADP,AT1,AT2,AT3)

C ------------------------------------------------

C THIS SUBROUTINE CHANGES INTERGERS TO ALPHNUMERIC CHARACTERS.

C IT CHECKS FOR BLANK SPACES AND REPLACES THEM WITH '0'.

C

C

 CHARACTER AIADP*5, A(5)*1, B(2)*1

 CHARACTER AT(3)*2

 CHARACTER*2 AT1,AT2,AT3

 INTEGER T1, T2, T3, T(3)

 T(1)=T1

 T(2)=T2
Appendix 1 77

 T(3)=T3

C

 WRITE(AIADP,10)IADP

 10 FORMAT(I5)

 READ(AIADP,15)A

 15 FORMAT(5A1)

 DO 20 I=1,5

 20 IF(A(I).EQ.' ')A(I)='0'

 WRITE(AIADP,15)A

C

C

 DO 100 J=1,3

 WRITE(AT(J),40)T(J)

 40 FORMAT(I2)

 READ(AT(J),50)B

 50 FORMAT(2A1)

 DO 70 I=1,2

 70 IF(B(I).EQ.' ')B(I)='0'

 WRITE(AT(J),50)B

 100 CONTINUE

C

 AT1=AT(1)

 AT2=AT(2)

 AT3=AT(3)

C

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE CODE2(DE,IDESAM)

C ---------------------------

C

C SUBROUTINE CODE2 SETS DEPTH OF OBS. AND DEP OF STA TO ALPH.

C AND CHECKS FOR BLANKS WHICH IT SETS TO '0'.

C

C

 CHARACTER IDESAM*5, A(5)*1

C

 ID=INT(DE*100.)

 WRITE(IDESAM,10)ID

 10 FORMAT(I5)

 READ(IDESAM,15)A

 15 FORMAT(5A1)

 DO 220 I=1,5

 220 IF(A(I).EQ.' ')A(I)='0'

 WRITE(IDESAM,15)A

C

 RETURN

 END
78 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C

C==============================================================================

C

 SUBROUTINE CODET(I,A)

C ---------------------

C

C THIS SUBROUTINE ZERO FILLS TIME

C

 CHARACTER A*4, EA(4)*1

C

 WRITE(A,10)I

 10 FORMAT(I4)

 READ(A,11)EA

 11 FORMAT(4A1)

 DO 20 J=1,4

 20 IF(EA(J).EQ.' ')EA(J)='0'

 WRITE(A,11)EA

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE CODE7(I,A)

C ---------------------

C

C THIS SUBROUTINE CHANGES INTERGERS TO CHARACTERS AND ZERO FILLS.

C WRITTEN TO BE USED ON DIST. FROM REF. POINT

C

 CHARACTER A*7, EA(7)*1

C

 WRITE(A,10)I

 10 FORMAT(I7)

 READ(A,11)EA

 11 FORMAT(7A1)

 DO 20 J=1,7

 20 IF(EA(J).EQ.' ')EA(J)='0'

 WRITE(A,11)EA

 RETURN

 END

C

C==============================================================================

C

 SUBROUTINE INITAL (DISRP,DESTA,NPV,DISHV,HLL,HLR,BWW,PER,DEPHV,MO,

 & NFS,

 & DESAM,DEPHH,AREA,V,PPMR,PPMP,PPMT,TQSVR,TQSVP,

 & TQSVT,TQSHR,TQSHP,TQSHT,GSA,WGSA,AGSA,HDIST,DEPXS,

 & VEL,BMP)

C -----------------------------------------------------------------
Appendix 1 79

 DIMENSION NFS(10,8),DISRP(10),DESTA(10),DESAM(10,8),NPV(10)

 DIMENSION DISHV(10),DEPHH(10,8),HDIST(100),DEPXS(100)

 DIMENSION VEL(100)

 DIMENSION DEPHV(10),HLL(10),HLR(10),AREA(10,8),V(10,8)

 & ,PPMR(10,8),PPMT(10,8),PPMP(10,8),

 & TQSVR(8),TQSVP(8),TQSVT(8),MO(11),TQSHR(8),TQSHP(8),

 & TQSHT(8),BWW(10),BMP(18),PER(10),GSA(5,10,8),AGSA(5),WGSA(5)

C INITIALIZING

 DO 15 I=1,10

 DISRP(I)=0.

 DESTA(I)=0.

 NPV(I)=0.

 DISHV(I)=0.

 HLL(I)=0.

 HLR(I)=0.

 BWW(I)=0.

 PER(I)=0.

 DEPHV(I)=0.

 MO(I)=0.

 DO 15 J=1,8

 NFS(I,J)=0

 DESAM(I,J)=0.

 DEPHH(I,J)=0.

 AREA(I,J)=0.

 V(I,J)=0.

 PPMR(I,J)=0.

 PPMP(I,J)=0.

 PPMT(I,J)=0.

 IF(I.GT.1)GO TO 14

 TQSVR(J)=0.

 TQSVP(J)=0.

 TQSVT(J)=0.

 TQSHR(J)=0.

 TQSHP(J)=0.

 TQSHT(J)=0.

 14 CONTINUE

 DO 15 K=1,5

 GSA(K,I,J)=0.

 IF(I.GT.1.OR.J.GT.1)GO TO 15

 WGSA(K)=0.

 AGSA(K)=0.

 15 CONTINUE

 DO 17 I=1,100

 HDIST(I)=0.

 DEPXS(I)=0.

 VEL(I)=0.

 IF(I.GT.18)GO TO 17

 BMP(I)=0.

 17 CONTINUE

 RETURN

 END
80 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C

C==============================================================================

C

 SUBROUTINE CALVEL (NV,NVV,DISHV,HDIST,NPV,DEPHH,DEPXS,TC,V,VEL)

C ---------------------------------------------------------------

 DIMENSION NPV(10)

 DIMENSION DISHV(10),DEPHH(10,8),HDIST(100),DEPXS(100)

 DIMENSION V(10,8),VEL(100)

C ****************************************************************

C DO LOOP 610 CALCULATES AVG. VELOCITIES IN EACH SUB-AREA. THIS IS

C DONE BY CALCULATHNG VELOCITIES AT EACH FOOT IN ELEVATION WITHIN

C THE SUB-AREA WHERE A MEASURED VELOCITY VERTICAL WAS TAKEN. THESE

C VELOCITIES ARE THEN AVERAGED OVER EACH SUB AREA.

C ****************************************************************

 IS=1

 DO 610 I=1,NV

 IF(I-NV)518,535,535

 518 DO 525 K=IS,NVV

 IF(DISHV(I)-HDIST(K))520,522,525

 520 IE=K-1

 GO TO 530

 522 IE=K

 GO TO 530

 525 CONTINUE

 530 NIS=K

 GO TO 540

 535 IE=NVV

 540 N=NPV(I)

 DO 590 J=1,N

 JM=J-1

 CT=0.

 DO 580 K=IS,IE

 IF(J-1)545,545,550

 545 DC=0.

 GO TO 554

 550 DC=DEPHH(I,JM)

 554 IF(DC-DEPXS(K))557,580,580

 557 DA=DEPXS(K)-DC+1.

 ZV=.1198+.00048*(TC*1.8+32.)

 DO 570 ID=1,1000

 DA=DA-1.

 IF(DA)575,575,560

 560 IF(J-N)562,565,562

 562 IF(DEPXS(K)-DEPHH(I,J)-DA)565,565,575

 565 V(I,J)=V(I,J)+VEL(K)*(1.+ZV)*(DA/DEPXS(K))**ZV

 570 CT=CT+1

 575 CONTINUE

 580 CONTINUE

 V(I,J)=V(I,J)/CT
Appendix 1 81

 590 CONTINUE

 IS=NIS

 610 CONTINUE

 RETURN

 END

C

C========================================================================

C

 SUBROUTINE GETDEFAULTS(LOPTION)

C ------------------------------

C 

C OPEN INPUT AND OUTPUT FILES

C 

 INCLUDE 'FMENUS.REC'

 CHARACTER REC*80, LOPTION*4

 CHARACTER*60 FILE(25),PROJECT,DIRECTORY,PRJDIR

 CHARACTER TEST*1,RECT1*1,ADP*3,RECT*1

 CHARACTER*9 OPTMAX(5,7)

 INTEGER IPAGES(3)

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /OPTIONS/ TEST,RECT1,ADP,IPAGES,RECT

 COMMON /MAXOPT/ OPTMAX

 INQUIRE(FILE='\SEDIMENT\DEFAULT',EXIST=EXIST)

 IF(EXIST)THEN

 IF(LOPTION.EQ.'LOAD')THEN

 OPEN(10,FILE='\SEDIMENT\DEFAULT',STATUS='OLD')

 READ(10,10,ERR=110)PROJECT

10 FORMAT(//29X,A60)

 CLOSE (10)

 ENDIF

 PRJDIR='\SEDIMENT\PROJECT\'//PROJECT(1:12)

 INQUIRE(FILE=PRJDIR,EXIST=EXIST)

 IF(EXIST)THEN

 OPEN(10,FILE=PRJDIR,STATUS='OLD')

 READ(10,11)DIRECTORY

11 FORMAT(//29X,A60)

 READ(10,30,ERR=100)OPTMAX(1,1),OPTMAX(1,2),OPTMAX(1,3),

 & OPTMAX(1,4),OPTMAX(1,5),OPTMAX(1,6),

 & FILE(1),FILE(2),FILE(4),FILE(5),FILE(6),FILE(7)

30 FORMAT(///29X,2A1,A3,3A1,6(/29X,A60))

 READ(10,31,ERR=100)OPTMAX(2,1),OPTMAX(2,2),OPTMAX(2,3),

 & OPTMAX(2,4),OPTMAX(2,5),OPTMAX(2,6),OPTMAX(2,7),

 & FILE(8),FILE(9)

31 FORMAT(///,29X,A2,1X,2(A5,1X),A6,1X,A6,2A2,

 & 2(/29X,A60))
82 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 READ(10,32,ERR=100)OPTMAX(3,1),OPTMAX(3,2),OPTMAX(3,3),

 & OPTMAX(3,4),OPTMAX(3,5),FILE(10),FILE(11)

32 FORMAT(///,30X,A1,1X,A5,1X,A6,1X,A6,A2,2(/29X,A60))

 READ(10,33,ERR=100)FILE(12),FILE(13),FILE(14)

33 FORMAT(//,3(/29X,A60))

 READ(10,34,ERR=100)FILE(15)

34 FORMAT(///,29X,A60)

 READ(10,35,ERR=100)FILE(16),FILE(17)

35 FORMAT(//,2(/29X,A60))

 READ(10,36,ERR=100)FILE(18),FILE(19)

36 FORMAT(//,2(/29X,A60))

 READ(10,37,ERR=100)OPTMAX(4,1),OPTMAX(4,2),OPTMAX(4,3),

 & OPTMAX(4,4),OPTMAX(4,5),OPTMAX(4,6),FILE(20),FILE(21)

37 FORMAT(///,30X,A1,1X,A1,2(1X,A5),2(1X,A6),2(/29X,A60))

 READ(10,38,ERR=100)OPTMAX(5,1),OPTMAX(5,2),OPTMAX(5,3),

 & OPTMAX(5,4),FILE(22),FILE(23)

38 FORMAT(///,30X,A5,1X,A5,1X,A6,1X,A6,2(/29X,A60))

 READ(10,39,ERR=100)FILE(24),FILE(25)

39 FORMAT(//,2(/29X,A60))

 

 TEST=OPTMAX(1,1)(1:1)

 RECT1=OPTMAX(1,2)(1:1)

 ADP=OPTMAX(1,3)(1:3)

 READ(OPTMAX(1,4),'(I1)')IPAGES(1)

 READ(OPTMAX(1,5),'(I1)')IPAGES(2)

 READ(OPTMAX(1,6),'(I1)')IPAGES(3)

 CLOSE (10)

 CALL CHDIRECTORY

 

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'PROJECT FILE DOES NOT EXIST..'C)

 ENDIF

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DEFAULT FILE DOES NOT EXIST..'C)

 ENDIF 

 RETURN

100 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'ERROR READING PROJECT FILE..'C)

 RETURN 

110 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'ERROR READING DEFAULT FILE..'C)
Appendix 1 83

 RETURN 

 END

C

C==============================================================================

C

 SUBROUTINE MENU

C ---------------

C

C LOAD SETUP FOR GRAPHICS AND LOAD FONT LIBRARY

C

 INCLUDE 'FMENUS.REC'

 CHARACTER*60 MSG

 INTEGER*2 OP,OPTION

 LOGICAL MORDAT /.TRUE./

 LOGICAL ERROR

 RECORD /MENUS/ MAINMEN

 RECORD /OPTS/ MAINOPT(9)

 MAINOPT(1).PLACE = 3

 MAINOPT(1).KEY = 76

 MAINOPT(1).CMD = ' Load 'C

 MAINOPT(2).PLACE = 10

 MAINOPT(2).KEY = 82

 MAINOPT(2).CMD = ' cReate 'C

 MAINOPT(3).PLACE = 19

 MAINOPT(3).KEY = 83

 MAINOPT(3).CMD = ' Save 'C

 MAINOPT(4).PLACE = 26

 MAINOPT(4).KEY = 67

 MAINOPT(4).CMD = ' Change 'C

 MAINOPT(5).PLACE = 34

 MAINOPT(5).KEY = 84

 MAINOPT(5).CMD = ' sTart 'C

 MAINOPT(6).PLACE = 41

 MAINOPT(6).KEY = 68

 MAINOPT(6).CMD = ' Directory 'C

 MAINOPT(7).PLACE = 52

 MAINOPT(7).KEY = 79

 MAINOPT(7).CMD = ' Options 'C

 MAINOPT(8).PLACE = 61

 MAINOPT(8).KEY = 77

 MAINOPT(8).CMD = ' Mkdir 'C

 MAINOPT(9).PLACE = 72

 MAINOPT(9).KEY = 81

 MAINOPT(9).CMD = ' Quit 'C

 MAINMEN.HIGH = 78

 MAINMEN.NORM = 23

 MAINMEN.FRAM = 0

 MAINMEN.ALIGN = 24

 MAINMEN.TITLE = ''C
84 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 CALL SLAPMENU( MAINMEN, MAINOPT)

 CALL SETMENU( MAINMEN, 9, 0, 1)

10 IF( MORDAT ) THEN

 OP = OPTION( MAINMEN, 9, 1)

 SELECT CASE ( OP )

 CASE ( 0 )

 CALL clean(0, 22, 12, 22, 78)

 CALL LPROJECT

 CALL DOPTIONS

 CASE ( 1 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CPROJECT

 CASE ( 2 )

 CALL clean(0, 22, 12, 22, 78)

 CALL SAVEDP

 CASE ( 3 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CFILES

 CASE ( 4 )

 CALL clean(0, 22, 12, 22, 78)

 CALL START(ERROR,MSG)

 IF(.NOT.ERROR)THEN

 CALL clean(0, 22, 12, 22, 78)

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22, 12, 14, MSG)

 ENDIF

 CASE ( 5 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CDIRECTORY

 CASE ( 6 )

 CALL clean(0, 22, 12, 22, 78)

 CALL COPTIONS

 CASE ( 7 )

 CALL clean(0, 22, 12, 22, 78)

 CALL MKDIRECTORY

 CASE ( 8 ) 

 CALL clean(0, 22, 12, 22, 78)

 MORDAT=.FALSE.

 END SELECT

 GOTO 10

 ENDIF

 RETURN

 END

C=========================================================================

 SUBROUTINE DPROJECT

C -------------------

 

C DISPLAY CURRENT PROJECT FILES

 
Appendix 1 85

 CHARACTER*60 FILE(25), TEMP, PROJECT, DIRECTORY

 INTEGER*2 DYNLEN,I

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL mvprint(7, 10, 31,'PROJECT INFORMATION'C)

 CALL clean(0, 8, 35, 8,46)

 CALL mvprint(8, 10, 30,'CURRENT PROJECT : 'C)

 I=DYNLEN(PROJECT)

 TEMP=PROJECT

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 9, 35, 9,46)

 CALL mvprint(9, 10, 30,'PROJECT DIRECTORY : 'C)

 I=DYNLEN(DIRECTORY)

 TEMP=DIRECTORY

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL mvprint(10, 10, 31,'PROJECT FILES'C)

 CALL clean(0, 11, 35, 11, 46)

 CALL mvprint(11, 10, 30,'SEDIMENT INPUT DATA : 'C)

 I=DYNLEN(FILE(1))

 TEMP=FILE(1)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 12, 35, 12, 46)

 CALL mvprint(12, 10, 30,'DISCHARGE INPUT DATA : 'C)

 I=DYNLEN(FILE(2))

 TEMP=FILE(2)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 13, 35, 13, 46)

 CALL mvprint(13, 10, 30,'3 PAGE OUTPUT FILE : 'C)

 I=DYNLEN(FILE(4))

 TEMP=FILE(4)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 14, 35, 14, 46)

 CALL mvprint(14, 10, 30,'HEIS OUTPUT FILE : 'C) 

 I=DYNLEN(FILE(5))

 TEMP=FILE(5)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 15, 35, 15, 46)

 CALL mvprint(15, 10, 30,'BED OUTPUT FILE : 'C) 

 I=DYNLEN(FILE(6))

 TEMP=FILE(6)

 TEMP(I+1:I+1)=CHAR(0)
86 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 16, 35, 16, 46)

 CALL mvprint(16, 10, 30,'SUMMARY DATA FILE : 'C) 

 I=DYNLEN(FILE(7))

 TEMP=FILE(7)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 RETURN

 END

C============================================================================

 SUBROUTINE FOPEN(ERROR,MSG)

C --------------------------------

C 

C OPEN INPUT AND OUTPUT FILES

C 

 CHARACTER*60 FILE(25), PROJECT, DIRECTORY, MSG

 LOGICAL ERROR,EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 ERROR = .FALSE.

 CALL FOPCHK(FILE(1),EXIST,MSG) 

 IF(EXIST)THEN

 ERROR=.TRUE.

 ENDIF

 CALL FOPCHK(FILE(2),EXIST,MSG) 

 IF(EXIST)THEN

 ERROR=.TRUE.

 ENDIF

 IF(.NOT.ERROR)THEN

 OPEN(11,FILE=FILE(1),STATUS='UNKNOWN')

 OPEN(12,FILE=FILE(2),STATUS='UNKNOWN')

 OPEN(13,FILE=FILE(4),STATUS='UNKNOWN')

 OPEN(14,FILE=FILE(5),STATUS='UNKNOWN')

 OPEN(15,FILE=FILE(6),STATUS='UNKNOWN')

 OPEN(30,FILE=FILE(7),STATUS='UNKNOWN')

 ENDIF

 RETURN

 END

C==========================================================================

 SUBROUTINE LPROJECT

C -------------------

C LOAD PROJECT
Appendix 1 87

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL settextposition(8, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 8, 35, 8, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(8, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 PROJECT=REC

 ENDIF

 call clean(0, 8, 35, 8, 46)

 I=DYNLEN(PROJECT)

 IF(INDEX(PROJECT,'PRJ').EQ.0.AND.

 & INDEX(PROJECT,'.').EQ.0)THEN

 PROJECT(I+1:I+5)='.PRJ'

 I=I+5

 ENDIF

 TEMP=PROJECT

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL GETDEFAULTS('SKIP')

 CALL DPROJECT

 RETURN

 END

C==========================================================================

 SUBROUTINE SAVEDP

C -----------------

C CHANGE CURRENT PROJECT

 

 CHARACTER*60 FILE(25), PROJECT, DIRECTORY, REC*80

 CHARACTER TEST*1, RECT1*1, ADP*3, RECT*1, DIR*60, CD*60

 CHARACTER MKDIR*60, PRJDIR*60

 INTEGER*2 I, J, DYNLEN

 CHARACTER*9 OPTMAX(5,7)

 INTEGER IPAGES(3)

 LOGICAL MORDAT, EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /OPTIONS/ TEST,RECT1,ADP,IPAGES,RECT

 COMMON /MAXOPT/ OPTMAX

 
88 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 MORDAT=.TRUE.

 OPEN(10,FILE='\SEDIMENT\DEFAULT',STATUS='UNKNOWN')

 I=DYNLEN(PROJECT)

 J=DYNLEN(DIRECTORY)

 DO 5 K=1,J

 IF(DIRECTORY(K:K).NE.' ')THEN

 L=J-K+1

 GO TO 6

 ENDIF

5 CONTINUE

6 DIRECTORY(1:L)=DIRECTORY(K:J)

 DO 7 M=L+1,12

 DIRECTORY(M:M)=' '

7 CONTINUE

 WRITE(10,10)PROJECT(1:12)

10 FORMAT('C DEFAULT FILES FOR SEDIMENT SYSTEM',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F CURRENT PROJECT FILE : ',A12)

 CLOSE(10)

 DIR='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=DIR,EXIST=EXIST)

 IF(EXIST)THEN

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 ELSE

 MKDIR='MKDIR \SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(MKDIR)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'CREATING DIRECTORY..'C)

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'CHANGING DIRECTORY..'C)

 ENDIF

 

 PRJDIR='\SEDIMENT\PROJECT\'//PROJECT(1:12)

 OPEN(10,FILE=PRJDIR,STATUS='UNKNOWN')

 OPTMAX(1,1)(1:1)=TEST

 OPTMAX(1,2)(1:1)=RECT1

 OPTMAX(1,3)(1:3)=ADP

 WRITE(OPTMAX(1,4),'(I1)')IPAGES(1)

 WRITE(OPTMAX(1,5),'(I1)')IPAGES(2)

 WRITE(OPTMAX(1,6),'(I1)')IPAGES(3)

 FILE(9)=FILE(2)

 FILE(10)=FILE(5)

 FILE(20)=FILE(6)

 FILE(22)=FILE(6)

 FILE(13)=FILE(11)

 FILE(15)=FILE(11)
Appendix 1 89

 FILE(16)=FILE(11)

 FILE(18)=FILE(11)

 FILE(24)=FILE(21)

 WRITE(10,20)DIRECTORY

20 FORMAT('C',21X,'DEFAULT FILES FOR SEDIMENT SYSTEM',/,

 & 'C--------1---------2---------3---------4',/,

 & 'D PROJECT DIRECTORY : ',A60)

 WRITE(10,30)OPTMAX(1,1),OPTMAX(1,2),OPTMAX(1,3),

 & OPTMAX(1,4),OPTMAX(1,5),OPTMAX(1,6),

 & FILE(1),FILE(2),FILE(4),FILE(5),FILE(6),FILE(7)

30 FORMAT('C',12X,'DEFAULT FILES FOR SUSPENDED SEDIMENT'

 & ' ANALYSIS PROGRAM',/,

 & 'P HH007',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & 2A1,A3,3A1,/,

 & 'F SEDIMENT INPUT DATA : ',A60,/,

 & 'F DISCHARGE INPUT DATA : ',A60,/,

 & 'F 3 PAGE OUTPUT FILE : ',A60,/,

 & 'F HEIS OUTPUT FILE : ',A60,/,

 & 'F BED OUTPUT FILE : ',A60,/,

 & 'F SUMMARY DATA FILE : ',A60)

 WRITE(10,31)

 & OPTMAX(2,1),OPTMAX(2,2),OPTMAX(2,3),OPTMAX(2,4),

 & OPTMAX(2,5),OPTMAX(2,6),OPTMAX(2,7),FILE(8),FILE(9)

31 FORMAT('C',14X,'DEFAULT FILES FOR SEDIMENT',

 & ' RETRIEVAL PROGRAM',/,

 & 'P HH080',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & A2,1X,2(A5,1X),A6,1X,A6,2A2,/,

 & 'F DISCHARGE MASTER : ',A60,/, 

 & 'F DISCHARGE OUTPUT DATA : ',A60)

 WRITE(10,32)

 & OPTMAX(3,1),OPTMAX(3,2),OPTMAX(3,3),OPTMAX(3,4),

 & OPTMAX(3,5),FILE(10),FILE(11)

32 FORMAT('C',23X,'HEIS DATA RETRIVAL PROGRAM',/,

 & 'P HH008',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : '

 & A1,1X,A5,1X,A6,1X,A6,A2,/, 

 & 'F HEIS INPUT FILE : ',A60,/,

 & 'F SEDIMENT OUTPUT FILE : ',A60)

 WRITE(10,33)FILE(12),FILE(13),FILE(14)

33 FORMAT('C',23X,'SEDIMENT CURVE FIT PROGRAM',/,

 & 'P HH048',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F DSS DISCHARGE INPUT : ',A60,/,
90 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 & 'F SEDIMENT INPUT FILE : ',A60,/,

 & 'F DAILY LOAD DATA OUTPUT : ',A60)

 WRITE(10,34)FILE(15)

34 FORMAT('C',15X,'REGRESSION ANALYSIS FOR SEDIMENT',

 & ' RATING CURVE PROGRAM',/, 

 & 'P HH049',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT INPUT FILE : ',A60)

 WRITE(10,35)FILE(16),FILE(17)

35 FORMAT('C',14X,'REGESSION ANALYSIS FOR VARIOUS ',

 & ' GRAIN SIZES PROGRAM',/,

 & 'P HH079',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT DATA FILE : ',A60,/,

 & 'F GRAIN SIZE OUTPUT FILE : ',A60)

 WRITE(10,36)FILE(18),FILE(19)

36 FORMAT('C',14X,'MEDIAN OF VARIOUS GRAIN SIZES PROGRAM',/,

 & 'P HH050',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT DATA FILE : ',A60,/,

 & 'F MEDIAN OF VARIOUS GRAIN: ',A60)

 WRITE(10,37)OPTMAX(4,1),OPTMAX(4,2),OPTMAX(4,3),

 & OPTMAX(4,4),OPTMAX(4,5),OPTMAX(4,6),FILE(20),FILE(21)

37 FORMAT('C',14X,'BED DATA RETRIVAL PROGRAM',/,

 & 'P HH082',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & A1,1X,A1,2(1X,A5),2(1X,A6),/,

 & 'F HEIS INPUT FILE : ',A60,/

 & 'F EXTRACTED BED DATA : ',A60)

 WRITE(10,38)OPTMAX(5,1),OPTMAX(5,2),OPTMAX(5,3),

 & OPTMAX(5,4),FILE(22),FILE(23)

38 FORMAT('C',13X,'BED DATA TABULAR LISTING PROGRAM',/,

 & 'P HH081',/,

 & 'C--------1---------2---------3---------4',/,

 & 'OPTION : ' 

 & A5,1X,A5,1X,A6,1X,A6,/,

 & 'F HEIS FILE : ',A60,/

 & 'F TABULAR BED DATA LIST : ',A60)

 WRITE(10,39)FILE(24),FILE(25)

39 FORMAT('C',14X,'BED MATERIAL PLOT PROGRAM',/,

 & 'P HH051',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F EXTRACTED BED DATE : ',A60,/

 & 'F MASTER TITLE FILE : ',A60)

 CLOSE (10)
Appendix 1 91

 RETURN

 END

C==========================================================================

 SUBROUTINE CPROJECT

C -------------------

C CREATE PROJECT

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 CHARACTER*9 OPTMAX(5,7)

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /MAXOPT/ OPTMAX

 CALL settextposition(8, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 8, 35, 8, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(8, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 PROJECT=REC

 ENDIF

 call clean(0, 8, 35, 8, 46)

 I=DYNLEN(PROJECT)

 IF(INDEX(PROJECT,'PRJ').EQ.0)THEN

 PROJECT(I+1:I+5)='.PRJ'

 I=I+5

 ENDIF

 TEMP=PROJECT

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 I=INDEX(PROJECT,'.')

 FILE(1)=PROJECT(1:I)//'SED'

 FILE(2)=PROJECT(1:I)//'DIS'

 FILE(4)=PROJECT(1:I)//'3PG'

 FILE(5)=PROJECT(1:I)//'HES'

 FILE(6)=PROJECT(1:I)//'BED'

 FILE(7)=PROJECT(1:I)//'SUM'

 FILE(8)='\SEDIMENT\MASTER\DISCHARG.MAS'

 FILE(9)=PROJECT(1:I)//'DIS'

 FILE(10)=PROJECT(1:I)//'HES'

 FILE(11)=PROJECT(1:I)//'SS1'

 FILE(12)=PROJECT(1:I)//'DSS'

 FILE(13)=PROJECT(1:I)//'SS1'
92 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 FILE(14)=PROJECT(1:I)//'DLD'

 FILE(15)=PROJECT(1:I)//'SS1'

 FILE(16)=PROJECT(1:I)//'SS2'

 FILE(17)=PROJECT(1:I)//'SIZ'

 FILE(18)=PROJECT(1:I)//'SS2'

 FILE(19)=PROJECT(1:I)//'MED'

 FILE(20)=PROJECT(1:I)//'BED'

 FILE(21)=PROJECT(1:I)//'EBD'

 FILE(22)=PROJECT(1:I)//'BED'

 FILE(23)=PROJECT(1:I)//'LST'

 FILE(24)=PROJECT(1:I)//'EBD'

 FILE(25)='\SEDIMENT\MASTER\TITLE.MAS'

 OPTMAX(1,1)='*'

 OPTMAX(1,2)='N'

 OPTMAX(1,3)='YES'

 OPTMAX(1,4)='0'

 OPTMAX(1,5)='0'

 OPTMAX(1,6)='0'

 OPTMAX(2,1)='-4'

 OPTMAX(2,2)='03045'

 OPTMAX(2,3)='03045'

 OPTMAX(2,4)='900101'

 OPTMAX(2,5)='900430'

 OPTMAX(2,6)=' 0'

 OPTMAX(2,7)=' 0'

 OPTMAX(3,1)='1'

 OPTMAX(3,2)='03045'

 OPTMAX(3,3)='900101'

 OPTMAX(3,4)='900430'

 OPTMAX(3,5)='12'

 OPTMAX(4,1)='2'

 OPTMAX(4,2)='2'

 OPTMAX(4,3)='03045'

 OPTMAX(4,4)='03045'

 OPTMAX(4,5)='900101'

 OPTMAX(4,6)='900430'

 OPTMAX(5,1)='03045'

 OPTMAX(5,2)='03045'

 OPTMAX(5,3)='900101'

 OPTMAX(5,4)='900430'

 CALL DPROJECT

 RETURN

 END

C==========================================================================

 

 SUBROUTINE CDIRECTORY

C -------------------

C CHANGE DIRECTORY'S NAME
Appendix 1 93

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL settextposition(9, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 9, 35, 9, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(9, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 DIRECTORY=REC

 ENDIF

 call clean(0, 9, 35, 9, 46)

 I=DYNLEN(DIRECTORY)

 TEMP=DIRECTORY

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL CHDIRECTORY

 RETURN

 END

C=========================================================================

 SUBROUTINE CHDIRECTORY

C ----------------------

C CHANGE DIRECTORY 

 INCLUDE 'FMENUS.REC'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY

 CHARACTER CD*60, DIR*60

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 I=DYNLEN(DIRECTORY)

 DIR='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=DIR,EXIST=EXIST)

 IF(EXIST)THEN

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DIRECTORY DOES NOT EXIST..'C)
94 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 ENDIF

 RETURN

 END

C=========================================================================

 SUBROUTINE MKDIRECTORY

C ----------------------

C MAKE DIRECTORY 

 INCLUDE 'FMENUS.REC'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY

 CHARACTER MKDIR*60, MD*60

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 I=DYNLEN(DIRECTORY)

 MKDIR='MKDIR \SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 MD='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=MD,EXIST=EXIST)

 IF(EXIST)THEN

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DIRECTORY ALREADY EXIST..'C)

 ELSE

 CALL SYSTEM(MKDIR)

 ENDIF

 RETURN

 END

C=========================================================================

 SUBROUTINE DOPTIONS

C -------------------

 

C DISPLAY CURRENT OPTIONS

 CHARACTER TEST*1,RECT1*1,ADP*3,RECT*1,CPAGES*3

 INTEGER IPAGES(3) 

 LOGICAL MORDAT, EXIST

 COMMON /OPTIONS/ TEST,RECT1,ADP,IPAGES,RECT

 CALL mvprint(17, 10, 31,'OPTIONS'C)

 CALL clean(0, 18, 35, 18, 46)

 CALL mvprint(18, 10, 30,'TYPE OF HEIS RECORD : 'C)

 CALL mvprint(0, 0, 14, RECT1//CHAR(0))
Appendix 1 95

 CALL clean(0, 19, 35, 19, 46)

 CALL mvprint(19, 10, 30,'CREATE A PRINTOUT : 'C)

 CALL mvprint(0, 0, 14, ADP//CHAR(0))

 IF(ADP.EQ.'YES')THEN

 IF(IPAGES(1).EQ.1)THEN

 CPAGES(1:1)='1'

 ELSE

 IF(IPAGES(2).EQ.1)THEN

 CPAGES(2:2)='2'

 IF(IPAGES(3).EQ.1)THEN

 CPAGES(3:3)='3'

 ELSE

 CPAGES='ALL'

 ENDIF

 ENDIF

 ENDIF

 ELSE

 CPAGES='000'

 ENDIF

 CALL clean(0, 20, 35, 20, 46)

 CALL mvprint(20, 10, 30,'EXCLUDE PAGES : 'C)

 CALL mvprint(0, 0, 14, CPAGES//CHAR(0))

 RETURN

 END

C=========================================================================

 SUBROUTINE COPTIONS

C -------------------

 

C CHANGE OPTIONS

 CHARACTER TEST*1,RECT1*1,ADP*3,RECT*1,CPAGES*3,REC*3

 INTEGER IPAGES(3) 

 LOGICAL MORDAT, EXIST

 COMMON /OPTIONS/ TEST,RECT1,ADP,IPAGES,RECT

 CALL mvprint(17, 10, 31,'OPTIONS'C)

 CALL clean(142, 18, 35, 18, 35)

 CALL mvprint(18, 10, 30,'TYPE OF HEIS RECORD : 'C)

 READ(*,'(A1)')REC

 IF(REC.NE.' ')THEN

 RECT1=REC(1:1)

 ENDIF

 IF(RECT1.EQ.'n')THEN

 RECT1='N'

 ELSEIF(RECT1.EQ.'a'.OR.RECT1.EQ.'A')THEN

 RECT1='A'

 ELSEIF(RECT1.EQ.'c'.OR.RECT1.EQ.'C')THEN
96 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 RECT1='C'

 ELSEIF(RECT1.EQ.'d'.OR.RECT1.EQ.'D')THEN

 RECT1='D'

 ELSE

 RECT1='N'

 ENDIF

 CALL mvprint(0, 0, 14, RECT1//CHAR(0))

 CALL clean(142, 19, 35, 19, 37)

 CALL mvprint(19, 10, 30,'CREATE A PRINTOUT : 'C)

 READ(*,'(A3)')REC

 IF(REC.NE.' ')THEN

 ADP=REC(1:3)

 ENDIF

 IF(INDEX(REC,'NO').GT.0)THEN

 ADP=' NO'

 ELSEIF(INDEX(REC,'no').GT.0)THEN

 ADP=' NO'

 ELSE

 ADP='YES'

 ENDIF

 CALL mvprint(0, 0, 14, ADP//CHAR(0))

 IF(ADP.EQ.'YES')THEN

 IF(IPAGES(1).EQ.1)THEN

 CPAGES(1:1)='1'

 ELSE

 IF(IPAGES(2).EQ.1)THEN

 CPAGES(2:2)='2'

 IF(IPAGES(3).EQ.1)THEN

 CPAGES(3:3)='3'

 ELSE

 CPAGES='ALL'

 ENDIF

 ENDIF

 ENDIF

 ELSE

 CPAGES='000'

 ENDIF

 CALL clean(0, 20, 35, 20, 46)

 CALL mvprint(20, 10, 30,'EXCLUDE PAGES : 'C)

 READ(*,'(A3)')REC

 IF(REC.NE.' ')THEN

 CPAGES=' '

 IF(INDEX(REC,'all').GT.0.OR.INDEX(REC,'ALL').GT.0.)THEN

 CPAGES='ALL'

 ENDIF

 IF(REC(1:1).EQ.'1')THEN

 CPAGES(1:1)='1'

 IPAGES(1)=1

 ENDIF

 IF(REC(2:2).EQ.'1')THEN

 CPAGES(2:2)='2'
Appendix 1 97

 IPAGES(2)=1

 ENDIF

 IF(REC(3:3).EQ.'1')THEN

 CPAGES(3:3)='3'

 IPAGES(3)=1

 ENDIF

 ENDIF

 CALL mvprint(0, 0, 14, CPAGES//CHAR(0))

 RETURN

 END

C=========================================================================

 SUBROUTINE CFILES

C -----------------

 

C CHANGE PROJECT FILES

 CHARACTER*60 FILE(25), TEMP, PROJECT, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL clean(142, 11, 35, 11, 46)

 CALL mvprint(11, 10, 30,'SEDIMENT INPUT DATA : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(1)=REC

 ENDIF

 I=DYNLEN(FILE(1))

 TEMP=FILE(1)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 11, 35, 11, 46)

 CALL mvprint(11, 35, 14, TEMP)

 CALL clean(142, 12, 35, 12, 46)

 CALL mvprint(12, 10, 30,'DISCHARGE INPUT DATA : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(2)=REC

 ENDIF

 I=DYNLEN(FILE(2))

 TEMP=FILE(2)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 12, 35, 12, 46)

 CALL mvprint(12, 35, 14, TEMP)

 CALL clean(142, 13, 35, 13, 46)

 CALL mvprint(13, 10, 30,'3 PAGE OUTPUT FILE : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(4)=REC

 ENDIF

 I=DYNLEN(FILE(4))

 TEMP=FILE(4)
98 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 13, 35, 13, 46)

 CALL mvprint(13, 35, 14, TEMP)

 CALL clean(142, 14, 35, 14, 46)

 CALL mvprint(14, 10, 30,'HEIS OUTPUT FILE : 'C) 

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(5)=REC

 ENDIF

 I=DYNLEN(FILE(5))

 TEMP=FILE(5)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 14, 35, 14, 46)

 CALL mvprint(14, 35, 14, TEMP)

 CALL clean(142, 15, 35, 15, 46)

 CALL mvprint(15, 10, 30,'BED OUTPUT FILE : 'C) 

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(6)=REC

 ENDIF

 I=DYNLEN(FILE(6))

 TEMP=FILE(6)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 15, 35, 15, 46)

 CALL mvprint(15, 35, 14, TEMP)

 CALL clean(142, 16, 35, 16, 46)

 CALL mvprint(16, 10, 30,'SUMMARY DATA FILE : 'C) 

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(7)=REC

 ENDIF

 I=DYNLEN(FILE(7))

 TEMP=FILE(7)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 16, 35, 16, 46)

 CALL mvprint(16, 35, 14, TEMP)

 RETURN

 END
Appendix 1 99

$debug

 INCLUDE 'FMENUS.INC'

 INCLUDE 'FGRAPH.FI'

C **** interface to call system services routine ****

 INTERFACE TO SUBROUTINE system[C](STRING)

 CHARACTER*1 STRING[REFERENCE]

 END

C 

C PROGRAM HH048

C -------------

C

C SEDIMENT CURVE FIT PROGRAM 

C WRITTEN FOR H&H BRANCH

C

************************************************************************

C WRITTEN BY J.P. CHIRISELEISON & T.J. DUFRENE - DEC 74

C CONVERTED TO HARRIS 800 BY R.E. JOLISSAINT - JAN 90

C CONVERTED TO MS-DOS BY R.E. JOLISSAINT - JULY 90

************************************************************************

C THIS PROGRAM CALCULATES UNRECORDED SUSPENDED SEDIMENT LOADS AS 

C RELATED TO DISCHARGE HYDROGRAPHS BY USING A STATISTICAL MODEL. 

C DATA FILES: 1) CONTAINS OBSERVED DISCHARGES AND SEDIMENT LOADS

C 2) DAILY DISCHARGES FOR THE WHOLE YEAR

C THE OUTPUT IS SAVED TO A DISK FILE 

C SUBROUTINES: REGRESS, LINEFIT, REORD, SSEDCF

************************************************************************

C CONVERTED TO THE PC WITH MENU ROUTINES BY: DON RAWSON

C SOURCE: HH048.FOR

C ENGID: HH048

C COMPLETED: 2/19/91

C

C MAIN

C ----

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER TITLE*50, PNAME*50

 INTEGER*1 getmouse,dummy

 INTEGER*2 mice

 TITLE='SEDIMENT CURVE FIT PROGRAM'C

 PNAME='ENG. ID: HH048 - Version 1.0 - 16 OCT 1990'C

 dummy=getmouse(-2,mice,mice)

 CALL PTITLE(TITLE,PNAME)

 CALL mvprint(22, 3, 15,'STATUS: 'C)

 CALL GETDEFAULTS('LOAD')

 CALL DPROJECT

 CALL MENU
100 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 CALL clearscreen ( $GCLEARSCREEN )

 STOP ' PROGRAM HH048 TERMINATED NORMALLY'

 END

C=========================================================================

 SUBROUTINE START(ERROR,MSG)

C ---------------------------

C

C SUBROUTINE STARTS COMPUTATIONS

C

 IMPLICIT DOUBLE PRECISION (A-H,O-Z)

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 DIMENSION ID(100),M(100),IY(100),Q(100),SED(3,100)

 DIMENSION SEDT(4,100),XJ(4),P(4),NSD(400)

 DIMENSION DQ(400),DATE(100),QT(100)

 DIMENSION SEDTT(3,100)

 LOGICAL ERT,ERROR

 CHARACTER AA*8

 CHARACTER BB*8

 CHARACTER TITLE*66,TEMP*66, MSG*60

 INTEGER*2 DYNLEN

 

 CALL clean(142, 18, 26, 18, 78)

 CALL mvprint(18, 10, 30,'ENTER TITLE : 'C)

 READ(*,'(A66)')TITLE

 I=DYNLEN(TITLE)

 TEMP=TITLE

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 18, 26, 18, 78)

 CALL mvprint(18, 26, 30, TEMP)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22, 12, 15,'PROCESSING [ ]'C)

 10 FORMAT(2A8)

 CALL FOPEN(ERROR,MSG)

 IF(ERROR)RETURN

 ERT = .FALSE.

 ERROR = .FALSE.

 KP=0

 J=0

 I=0

 KOUNT=0

C *** READ: LINE NUM, DATE, DISCHARGE, SEDIMENT LOADS ***

 30 I=I+1

 READ(11,*,ERR=909)DLN,DATE(I),Q(I),T,SI
Appendix 1 101

C 31 FORMAT(V)

 IF(DATE(I))35,40,33

 33 KOUNT=KOUNT+1

C --- CUT DATE TO DAY, MONTH, YEAR ---

 ID(I)=DATE(I)/10000.

 DA=ID(I)

 YN=(DATE(I)/10000.-DA)*100.

 M(I)=YN

 XM=M(I)

 Y=(YN-XM)*100.

 IY(I)=Y+.01

C --- TOTAL SEDIMENT LOAD ---

 SED(1,I)=T

C --- SILT-CLAY FRACTION LOAD ---

 SED(3,I)=SI

 GO TO 30

 35 WRITE (*,*)'DATE BEING READ AS MINUS'

 GO TO 30

 40 CONTINUE

 

C *** CALCULATE AMOUNT OF SAND = TOTAL - SILT ***

 DO 45 I=1,KOUNT

 SED(2,I)=SED(1,I)-SED(3,I)

 45 CONTINUE

C *** CONVERT OBSERVED Q TO CFS ***

 DO 110 I=1,KOUNT

 QT(I)=Q(I)*1000.

110 CONTINUE

C *** CONVERT SEDIMENT Q TO 1000 TONS/DAY ***

 DO 60 J=1,3

 DO 60 I=1,KOUNT

 SEDT(J,I)=Q(I)*SED(J,I)*.00269663

 SEDTT(J,I)=SEDT(J,I)*1000.

 60 CONTINUE

C *** PRINT OUT SEDIMENT TABLE ***

C --- CALCULATE TOP OF PAGE SPACING ---

 KOUTEM=KOUNT

 IF(KP.EQ.1)GO TO 100

 KBGIN=1

 KEND=KOUNT

 59 NSPACT=(46-KOUNT)/2

 NSPACB=46-KOUNT-NSPACT

 IF(46-KOUNT)63,64,75

 63 KEND=40

 NSPACT=3

 NSPACB=3

 75 CONTINUE

 DO 61 ISPA=1,NSPACT

 61 WRITE(12,62)

 62 FORMAT(/)
102 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 64 WRITE(12,65)TITLE

 65 FORMAT(A72)

C --- PRINT HEADER ---

 WRITE(12,70)

 70 FORMAT(14X,'Q',12X,'SUSPENDED SEDIMENT OBSERVATIONS',/,3X,

 & 'DATE',5X,'1000',9X,'P.P.M.',14X,'1000 TONS/DAY',/,

 & 'MO DA YR CFS',6X,'TOT SAND SILT TOTAL ',

 & 'SAND SILT',/,64('-'))

C --- PRINT TABLE ---

 DO 90 I=KBGIN,KEND

 WRITE(12,80)M(I),ID(I),IY(I),Q(I),(SED(J,I),J=1,3),

 & (SEDT(JJ,I),JJ=1,3)

 80 FORMAT(I3,2('/',I2),F9.3,F7.0,2F6.0,F10.3,2F9.3)

 90 CONTINUE

C --- CALCULATE BOTTOM OF PAGE SPACING ---

 IF(NSPACB.LT.1)GO TO 95

 DO 91 ISPA=1,NSPACB

 91 WRITE(12,62)

 95 IF(KOUNT.LE.46)GO TO 100

 KBGIN=41

 KEND=KOUNT

 KOUNT=KOUNT-40

 GO TO 59

100 CONTINUE

 KOUNT=KOUTEM

 CALL REGRESS(KOUNT,QT,SEDTT,XJ,P)

 XJ(4)=1.0

 P(4)=1.0

 CALL REORD(NSD,DQ,M5,ERROR)

 IF(ERROR)GOTO 909

 NDY=M5+338

 L=0

 SEDT(4,1)=100.

 SEDT(4,2)=DQ(2)

 SEDT(4,3)=DQ(NDY)

 SEDT(4,4)=100.

 SEDT(4,5)=0.0

 DO 200 L=1,4

 NDYP1=NDY+1

 LIM=L

 IF(LIM.LT.4)GO TO 150

 DATE(2)=NSD(2)

 DATE(3)=NSD(NDY)

 DATE(4)=NSD(NDYP1)

 DATE(5)=0.0

 DATE(2)=NSD(2)
Appendix 1 103

150 CONTINUE

 CALL SSEDCF(NDY,NSD,DQ,DATE,SEDT,LIM,XJ,P,TITLE)

200 CONTINUE

 CLOSE(11)

 CLOSE(12)

 CALL clean(0, 22, 12, 22, 78)

 RETURN

555 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22, 15, 30,'....ERROR PROCESSING DATA....'C)

 ERROR = .TRUE.

 RETURN

909 CONTINUE

 CALL mvprint(22, 15, 30,'ERROR READING DATA FILE.'C)

 ERROR = .TRUE.

 RETURN

 END

C========================================================================

 SUBROUTINE REGRESS (NP, X, Y, SLOPE, YCUT)

C THIS ROUTINE CALCULATES A STRAIGHT LINE EQUATION FOR UP TO 

C 400 PAIRS OF POINTS ON A LOG-LOG BASIS. 

C CALLED BY: MAIN CALLS: LINEFIT

 IMPLICIT DOUBLE PRECISION (A-H,O-Z)

 DIMENSION X(100),Y(3,100),SLOPE(4),YCUT(4)

 I=0

 DO 25 I=1,NP

 DO 24 J=1,3

 Y(J,I)=ALOG10(Y(J,I))

 24 CONTINUE

 X(I)=ALOG10(X(I))

 25 CONTINUE

 CALL LINEFIT(1,NP,X,Y,SLOPE,YCUT)

 DO 30 M=1,3

 YCUT(M)=10.**YCUT(M)

 30 CONTINUE

 RETURN

 END
104 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C=======================================================================

 SUBROUTINE LINEFIT (IN, LAST, X, Y, S, YI)

C CALLED BY: REGRESS

 IMPLICIT DOUBLE PRECISION (A-H,O-Z)

 DIMENSION X(LAST), Y(3,LAST), S(4), YI(4)

 N=LAST-IN+1

 DO 20 J=1,3

 S1=0

 S2=0

 S3=0

 S4=0

 DO 10 I=IN,LAST

 S1=S1+X(I)

 S2=S2+Y(J,I)

 S3=S3+X(I)*Y(J,I)

 S4=S4+X(I)*X(I)

10 CONTINUE

 S(J)=(N*S3-S1*S2)/(N*S4-S1*S1)

 YI(J)=(S2*S4-S1*S3)/(N*S4-S1*S1)

20 CONTINUE

 RETURN

 END

C========================================================================

 SUBROUTINE REORD(NSD, DQ, M5, ERROR)

C ROUTINE READS THE DAILY DISCHARGES AND PUTS THEM IN DATE ORDER.

C CALLED BY: MAIN

 IMPLICIT DOUBLE PRECISION (A-H,O-Z)

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 DIMENSION M(12),NSD(400),DQ(400)

 CHARACTER AA*8

 LOGICAL ERROR

 

 ERROR = .FALSE.

 5 FORMAT(A8)

 JJJ=1

C *** READ: LINE NUM, START & END DATE & DISCHARGE ***

 READ(13,*)DMY,NSD1,DQ1,NSD2,DQ2

 IF(JJJ.EQ.1)THEN

 JJJ=2

 call mvputch(22 ,24, 4, 179)

 ELSEIF(JJJ.EQ.2)THEN
Appendix 1 105

 JJJ=3

 call mvputch(22 ,24, 4, 45)

 ELSEIF(JJJ.EQ.3)THEN

 JJJ=4

 call mvputch(22 ,24, 4, 92)

 ELSEIF(JJJ.EQ.4)THEN

 JJJ=1

 call mvputch(22 ,24, 4, 47)

 ENDIF

C *** CHEACK FOR LEAP YEAR ***

 SD=NSD1+1

 SD10=SD/100.

 N10=SD10

 SDF=N10

 IY=(SD10-SDF)*100.+.01

 Y=IY

 Y=Y/4.

 IY4=IY/4

 YI=IY4

C *** SET NUMBER OF DAYS IN MONTHS ***

 DO 10 I=1,12

 M(I)=31

 10 CONTINUE

 IF(Y-YI)28,29,28

 28 M(5)=28

 GO TO 30

 29 M(5)=29

 30 KT=1

 M5=M(5)

 M(2)=30

 M(7)=30

 M(9)=30

 M(12)=30

C *** SET MONTH = OCTOBER ***

 MO=10

 J=1

 IN=IY-1

 IYER=IN

 KOUNT=1

C *** READ DAILY DISCHARGES, FIRST MONTH = OCT ***

 DO 100 I=2,362,10

 JJ=I+9

 READ(13,*,ERR=909)DMY,(DQ(JH),JH=I,JJ)

 IF(JJJ.EQ.1)THEN

 JJJ=2

 call mvputch(22 ,24, 4, 179)

 ELSEIF(JJJ.EQ.2)THEN

 JJJ=3

 call mvputch(22 ,24, 4, 45)
106 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 ELSEIF(JJJ.EQ.3)THEN

 JJJ=4

 call mvputch(22 ,24, 4, 92)

 ELSEIF(JJJ.EQ.4)THEN

 JJJ=1

 call mvputch(22 ,24, 4, 47)

 ENDIF

100 CONTINUE

 DO 200 N=1,366

 IF(N.EQ.1) GO TO 35

 KT=KT+1

 IF(DQ(N).EQ.0.)GO TO 201

 IF(KT.LE.M(J))GO TO 35

 KT=1

 J=J+1

 MO=J-3

 IF(J.EQ.1)MO=10

 IF(J.EQ.2)MO=11

 IF(J.EQ.3)MO=12

 IYER=IY

 IF(J.LT.4)IYER=IN

 35 KOUNT=KOUNT+1

 NSD(KOUNT)=IYER+100*MO+10000*KT

200 CONTINUE

C *** COPY START & END DATE & DISCHARGE TO ARRAYS ***

201 KOUNT=KOUNT+1

 NSD(1)=NSD1

 DQ(1)=DQ1

 NSD(KOUNT)=NSD2

 DQ(KOUNT)=DQ2

 KOUNT=KOUNT+1

 NSD(KOUNT)=0

 DQ(KOUNT)=0

 CLOSE(13)

 RETURN

909 ERROR = .TRUE.

 RETURN

 END

C========================================================================

 SUBROUTINE SSEDCF(NDY,KDATE,BDISCH,DATE,SEDT,LYT,XJD,PD,TITLE)

C THIS ROUTINE FITS A CURVE THROUGH THERODICAL SUSPENDED SEDIMENT

C LOADS AND ADJUSTES IT TO OBSERVED SUSPENDED SEDIMENT LOADS.

C CALLED BY: MAIN

 IMPLICIT DOUBLE PRECISION (A-H,O-Z)
Appendix 1 107

 DIMENSION Q(425),ST(425),SA(425),SO(425),NDM(12)

 DIMENSION XJD(4),PD(4)

 DIMENSION KDATE(400),BDISCH(400),DATE(100),SEDT(4,100)

 DIMENSION SP(12,35),MP(12,35),XM(3)

 DIMENSION XSP(12,35)

 CHARACTER ND(367)*1

 CHARACTER MT(3)*3

 CHARACTER IN(12,31)*1

 CHARACTER TITLE*66

 CHARACTER TSS(3)*31

C *** INITILIZATIONS ***

 DO 100 I=1,425

 Q(I)=0.

 ST(I)=0.

 SA(I)=0.

 SO(I)=0.

 IF(I.GT.367)GO TO 100

 ND(I)=1H 

100 CONTINUE

 MT(1)=3HAVG

 MT(2)=3HMAX

 MT(3)=3HMIN

 DO 101 I=1,12

 DO 102 J=1,35

102 SP(I,J)=0.

 SP(I,34)=9999999.

101 NDM(I)=31

 NDM(2)=30

 NDM(7)=30

 NDM(9)=30

 NDM(12)=30

 LSR=0

 KD=0

 KJ=0

 TSS(1)=18H TOTAL

 TSS(2)=31HSAND (COARSER THAN 0.0625 M.M.)

 TSS(3)=30H SILT (FINER THAN 0.0625 M.M.)

 BQ=BDISCH(1)

 KB=KDATE(1)

 IC=0

C --- END INITILIZATIONS ---

 DO 110 I=1,NDY

 IC=IC+1

 IP=I+1

 Q(I)=BDISCH(IP)

 K=KDATE(IP)

 IF(K.LE.0)GO TO 111

 KA=K

 IF(I.NE.152)GO TO 110

 LY=28
108 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 PYK=K

 IYP=(PYK/100.-103.)*100.+1900.0001

 K=K/10000

 IF(K.NE.29)GO TO 110

 LY=K

 IYP=(PYK/100.-2902.)*100.+1900.0001

110 CONTINUE

111 NDM(5)=LY

 IYPM=IYP-1

 AQ=Q(IC-1)

 BSO=SEDT(LYT,1)

 DO 120 I=1,367

 IP=I+1

 SOT=SEDT(LYT,IP)

 K=DATE(IP)

 K100=K/100

 IF(K.EQ.0)GO TO 121

 ID=K100/100

 XK=K100

 XK=XK/100.

 DI=ID

 M=(XK-DI)*100.+.01

 IF(M.EQ.9)LSR=9

 IF(LSR.EQ.9.AND.M.EQ.10)GO TO 120

 N=0

 DO 118 J=1,12

 KM=J-3

 IF(J.LT.4)KM=J+9

 IF(KM.EQ.M)GO TO 119

118 N=N+NDM(J)

119 N=N+ID

 SO(N)=SOT

 ND(N)=1H#

120 ASO=SOT

121 CONTINUE

 KB=31-KB/10000

 KA=KA/10000

 L=LY+337

 DO 122 II=1,L

 I=L+1-II

 IKB=I+KB

 Q(IKB)=Q(I)

122 SO(IKB)=SO(I)

 IF(KB.EQ.0)GO TO 124

 DO 123 I=1,KB

123 Q(I)=BQ

 SO(1)=BSO
Appendix 1 109

124 N=L+1+KB

 NN=L+KA+KB

 IF(NN.LT.N)GO TO 126

 DO 125 I=N,NN

125 Q(I)=AQ

 SO(NN)=ASO

126 NNM=NN-1

 XJ=XJD(LYT)

 P=PD(LYT) 

 DO 140 I=1,NN

 ST(I)=P*(Q(I)*1000.)**XJ

140 ST(I)=ST(I)/1000.

400 CONTINUE

 DO 450 I=1,NN

 KD=KD+1

 IF(KD-1)420,420,410

410 IF(SO(KD))450,450,460

420 LD=1

450 CONTINUE

460 DADIF=KD-LD

 IF(DADIF.LE.1.)GO TO 790

C *** PROGRAM BOMBS AT ALONG10 IF SO(LD) = 0 

C *** CHANGED TO SO(LD) TO .0001

 IF(SO(LD).NE.0)THEN

 VDL=ALOG10(ST(LD))-ALOG10(SO(LD))

 ELSE

 VDL=ALOG10(ST(LD))-ALOG10(.0001)

 ENDIF

 VDR=ALOG10(ST(KD))-ALOG10(SO(KD))

 M=DADIF-1.

 VDIF=VDL-VDR

C *** CHECK ADDED DURING CONVERSION TO HARRIS ***

C *** PROGRAM BOMBS AT 700 - DIVISION BY ZERO ***

 IF (LYT.EQ.4 .AND. VDL.EQ.VDR) VDIF=.00001

 IF(VDL)470,700,480

470 IF(VDR)490,700,700

480 IF(VDR)700,700,495

490 IF(VDIF)498,498,499

495 IF(VDIF)497,496,496

496 LU=1

 VDIS=VDR

501 MPP=-1

 GO TO 505

497 LU=0
110 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 VDIS=VDL

 GO TO 501

498 LU=1

 VDIS=VDR

 GO TO 502

499 LU=0

 VDIS=VDL

502 MPP=1

505 IF(LU)506,506,507

506 MD=KD

 GO TO 508

507 MD=LD

508 T=DADIF

 DO 600 I=1,M

 T=T-1.

 IF(LU)606,606,605

605 MD=MD+1

 GO TO 607

606 MD=MD-1

607 ANTL=T/DADIF*ABS(VDIF)+ABS(VDIS)

 IF(MPP)610,610,611

610 SA(MD)=ALOG10(ST(MD))-ANTL

 GO TO 612

611 SA(MD)=ALOG10(ST(MD))+ANTL

612 SA(MD)=10.**(SA(MD))

600 CONTINUE

 GO TO 780

700 FRL=ABS(VDL/VDIF*DADIF)

 FRR=ABS(VDR/VDIF*DADIF)

 ITL=FRL

 ITR=FRR

 IF(ITR.EQ.0.AND.ITL.EQ.0)GO TO 770

 MD=KD

 T=FRR

 IF(ITR.EQ.0)GO TO 740

 DO 730 I=1,ITR

 MD=MD-1

 T=T-1.

 SA(MD)=ALOG10(ST(MD))-T/FRR*VDR

 SA(MD)=10.**(SA(MD))

730 CONTINUE

740 MD=LD

 T=FRL

 IF(ITL.EQ.0)GO TO 780

 DO 760 I=1,ITL

 MD=MD+1

 T=T-1.

 SA(MD)=ALOG10(ST(MD))-T/FRL*VDL
Appendix 1 111

 SA(MD)=10.**(SA(MD))

760 CONTINUE

 GO TO 780

770 ITL=LD+1

 ITR=KD-1

 DO 775 I=ITL,ITR

775 SA(I)=ST(I)

780 CONTINUE

790 LD=KD

 IF(KD-NNM)400,800,800

800 DO 830 I=1,NN

 IF(SO(I))830,830,810

810 SA(I)=SO(I)

830 CONTINUE

 DO 860 I=1,L

 IKB=I+KB

860 SA(I)=SA(IKB)

 KD=0

 DO 861 I=1,12

 L=I-3

 IF(I.LT.4)L=I+9

 J=NDM(I)

 DO 861 K=1,J

 KD=KD+1

 SP(L,K)=SA(KD)

 IF(SP(L,K).GT.SP(L,33))SP(L,33)=SP(L,K)

 IF(SP(L,K).LT.SP(L,34))SP(L,34)=SP(L,K)

 SP(L,35)=SP(L,35)+SP(L,K)

 IN(L,K)=ND(KD)

861 CONTINUE

 GT=0.

 XM(2)=0.

 XM(3)=99999999.

 DO 864 I=1,12

 IF(SP(I,33).GT.XM(2))XM(2)=SP(I,33)

 IF(SP(I,34).LT.XM(3))XM(3)=SP(I,34)

 J=I+3

 IF(I.GT.9)J=I-9

 XNDM=NDM(J)

 SP(I,32)=SP(I,35)/XNDM

 SP(I,35)=SP(I,35)/1000.

864 GT=GT+SP(I,35)

 D=LY+337

 XM(1)=(GT*1000.)/D
112 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 DO 865 I=1,12

 DO 865 J=1,35

 XSP(I,J)=SP(I,J)+0.5

865 MP(I,J)=INT(XSP(I,J))

 IF(LYT.LT.4)GO TO 869

 WRITE(12,866)TITLE,IYPM,IYP

866 FORMAT(//,20X,'DAILY DISCHARGE IN 1000 CFS FOR',/,

 & A72,/,22X,'--- WATER YEAR',I5,'-',I4,' ---',//,5X,

 & 'OCT NOV DEC JAN FEB MAR APR MAY JUN JUL ',

 & 'AUG SEP',/)

 GO TO 876

869 WRITE(12,870)TITLE,TSS(LYT),IYPM,IYP

870 FORMAT(//,13X,'SUSPENDED SEDIMENT LOADS IN 1000 TONS/DAY',

 & ' FOR',/,A72,/,16X,A32,/,22X,'--- WATER YEAR',I5,

 & '-',I4,' ---',//,5X,

 & 'OCT NOV DEC JAN FEB MAR APR MAY JUN JUL ',

 & 'AUG SEP',/)

876 DO 880 I=1,LY

880 WRITE(12,862)I,(MP(J,I),IN(J,I),J=10,12),(MP(K,I),

 & IN(K,I),K=1,9),I

862 FORMAT(I3,I5,11(A1,I4),A1,I3)

 LYP=LY+1

 DO 890 I=LYP,30

890 WRITE(12,930)I,(MP(J,I),IN(J,I),J=10,12),MP(1,I),IN(1,I),

 & (MP(K,I),IN(K,I),K=3,9),I

930 FORMAT(I3,I5,3(A1,I4),A1,I9,6(A1,I4),A1,I3)

 I=31

 WRITE(12,931)I,(MP(J,I),IN(J,I),J=10,12,2),(MP(K,I),IN(K,I),

 & K=1,7,2),MP(8,I),IN(8,I),I

931 FORMAT(I3,I5,A1,I9,A1,I4,3(A1,I9),A1,I4,A1,I8,/,4X,60(1H-))

 DO 940 I=32,34

 N=I-31

 DO 939 J=1,12

 IF(SP(J,I).GT.99.9)GO TO 950

939 CONTINUE

 WRITE(12,938)MT(N),(SP(J,I),J=10,12),(SP(K,I),K=1,9),XM(N)

938 FORMAT(A3,12F5.1,F9.3)

 GO TO 940

950 WRITE(12,941)MT(N),(MP(J,I),J=10,12),(MP(K,I),K=1,9),XM(N)

941 FORMAT(A3,12I5,F9.3)

940 CONTINUE

 I=35

 WRITE(12,942)(SP(J,I),J=10,12),(SP(K,I),K=1,9),GT

942 FORMAT('TOT',12F5.1,F9.3,///)
Appendix 1 113

 IF(LYT.LT.4)GO TO 961

 WRITE(12,960)

960 FORMAT(/,'NOTE:',/,4X,'TOTALS ARE IN 1,000,000 CFS')

 GO TO 999

961 WRITE(12,943)

943 FORMAT(/,'NOTES:',/,4X,'1) TOTALS ARE IN 1,000,000 TONS',29X,

 & 'XJ',/,4X,'2) THEORETICAL SEDIMENT VALUES ARE COMPUTED ',

 & 'FROM Q(SED)=P(Q)',/,7X,'USING DAILY DISCHARGES(Q) AND ',

 & 'THEN ARE ADJUSTED TO ACCOMMODATE',/,7X,'OBSERVED VALUES ',

 & 'WHICH ARE NOTED WITH A #.')

 WRITE(12,944)XJ,P

944 FORMAT(10X,'XJ=',E14.6,' & P=',E14.6,////)

999 CONTINUE

 RETURN

 END

C

C========================================================================

C

 SUBROUTINE GETDEFAULTS(LOPTION)

C ------------------------------

C 

C OPEN INPUT AND OUTPUT FILES

C 

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER REC*80, LOPTION*4

 CHARACTER*60 FILE(25),PROJECT,DIRECTORY,PRJDIR

 CHARACTER*9 OPTMAX(5,7)

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /MAXOPT/ OPTMAX

 INQUIRE(FILE='\SEDIMENT\DEFAULT',EXIST=EXIST)

 IF(EXIST)THEN

 IF(LOPTION.EQ.'LOAD')THEN

 OPEN(10,FILE='\SEDIMENT\DEFAULT',STATUS='OLD')

 READ(10,10,ERR=110)PROJECT

10 FORMAT(//29X,A60)

 CLOSE (10)

 ENDIF

 PRJDIR='\SEDIMENT\PROJECT\'//PROJECT(1:12)

 INQUIRE(FILE=PRJDIR,EXIST=EXIST)
114 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 IF(EXIST)THEN

 OPEN(10,FILE=PRJDIR,STATUS='OLD')

 READ(10,11)DIRECTORY

11 FORMAT(//29X,A60)

 READ(10,30,ERR=100)OPTMAX(1,1),OPTMAX(1,2),OPTMAX(1,3),

 & OPTMAX(1,4),OPTMAX(1,5),OPTMAX(1,6),

 & FILE(1),FILE(2),FILE(4),FILE(5),FILE(6),FILE(7)

30 FORMAT(///29X,2A1,A3,3A1,6(/29X,A60))

 READ(10,31,ERR=100)OPTMAX(2,1),OPTMAX(2,2),OPTMAX(2,3),

 & OPTMAX(2,4),OPTMAX(2,5),OPTMAX(2,6),OPTMAX(2,7),

 & FILE(8),FILE(9)

31 FORMAT(///,29X,A2,1X,2(A5,1X),A6,1X,A6,2A2,

 & 2(/29X,A60))

 READ(10,32,ERR=100)OPTMAX(3,1),OPTMAX(3,2),OPTMAX(3,3),

 & OPTMAX(3,4),OPTMAX(3,5),FILE(10),FILE(11)

32 FORMAT(///,30X,A1,1X,A5,1X,A6,1X,A6,A2,2(/29X,A60))

 READ(10,33,ERR=100)FILE(12),FILE(13),FILE(14)

33 FORMAT(//,3(/29X,A60))

 READ(10,34,ERR=100)FILE(15)

34 FORMAT(///,29X,A60)

 READ(10,35,ERR=100)FILE(16),FILE(17)

35 FORMAT(//,2(/29X,A60))

 READ(10,36,ERR=100)FILE(18),FILE(19)

36 FORMAT(//,2(/29X,A60))

 READ(10,37,ERR=100)OPTMAX(4,1),OPTMAX(4,2),OPTMAX(4,3),

 & OPTMAX(4,4),OPTMAX(4,5),OPTMAX(4,6),FILE(20),FILE(21)

37 FORMAT(///,30X,A1,1X,A1,2(1X,A5),2(1X,A6),2(/29X,A60))

 READ(10,38,ERR=100)OPTMAX(5,1),OPTMAX(5,2),OPTMAX(5,3),

 & OPTMAX(5,4),FILE(22),FILE(23)

38 FORMAT(///,30X,A5,1X,A5,1X,A6,1X,A6,2(/29X,A60))

 READ(10,39,ERR=100)FILE(24),FILE(25)

39 FORMAT(//,2(/29X,A60))

 

 CLOSE (10)

 CALL CHDIRECTORY

 

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'PROJECT FILE DOES NOT EXIST..'C)

 ENDIF

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DEFAULT FILE DOES NOT EXIST..'C)
Appendix 1 115

 ENDIF 

 RETURN

100 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'ERROR READING PROJECT FILE..'C)

 RETURN 

110 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'ERROR READING DEFAULT FILE..'C)

 RETURN 

 END

C

C==============================================================================

C

 SUBROUTINE MENU

C ---------------

C

C LOAD SETUP FOR GRAPHICS AND LOAD FONT LIBRARY

C

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER MSG*60

 INTEGER*2 OP,OPTION

 LOGICAL MORDAT /.TRUE./

 LOGICAL ERROR

 RECORD /MENUS/ MAINMEN

 RECORD /OPTS/ MAINOPT(9)

 MAINOPT(1).PLACE = 3

 MAINOPT(1).KEY = 76

 MAINOPT(1).CMD = ' Load 'C

 MAINOPT(2).PLACE = 10

 MAINOPT(2).KEY = 82

 MAINOPT(2).CMD = ' cReate 'C

 MAINOPT(3).PLACE = 19

 MAINOPT(3).KEY = 83

 MAINOPT(3).CMD = ' Save 'C

 MAINOPT(4).PLACE = 26

 MAINOPT(4).KEY = 67

 MAINOPT(4).CMD = ' Change 'C

 MAINOPT(5).PLACE = 34

 MAINOPT(5).KEY = 84

 MAINOPT(5).CMD = ' sTart 'C

 MAINOPT(6).PLACE = 41

 MAINOPT(6).KEY = 68

 MAINOPT(6).CMD = ' Directory 'C

 MAINOPT(7).PLACE = 52

 MAINOPT(7).KEY = 79

 MAINOPT(7).CMD = ' Options 'C

 MAINOPT(8).PLACE = 61

 MAINOPT(8).KEY = 77

 MAINOPT(8).CMD = ' Mkdir 'C
116 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 MAINOPT(9).PLACE = 72

 MAINOPT(9).KEY = 81

 MAINOPT(9).CMD = ' Quit 'C

 MAINMEN.HIGH = 78

 MAINMEN.NORM = 23

 MAINMEN.FRAM = 0

 MAINMEN.ALIGN = 24

 MAINMEN.TITLE = ''C

 CALL SLAPMENU( MAINMEN, MAINOPT)

 CALL SETMENU( MAINMEN, 9, 0, 1)

10 IF( MORDAT ) THEN

 OP = OPTION( MAINMEN, 9, 1)

 SELECT CASE ( OP )

 CASE ( 0 )

 CALL clean(0, 22, 12, 22, 78)

 CALL LPROJECT

 CASE ( 1 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CPROJECT

 CASE ( 2 )

 CALL clean(0, 22, 12, 22, 78)

 CALL SAVEDP

 CASE ( 3 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CFILES

 CASE ( 4 )

 CALL clean(0, 22, 12, 22, 78)

 CALL START(ERROR,MSG)

 IF(.NOT.ERROR)THEN

 CALL clean(0, 22, 12, 22, 78)

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22,12,14,MSG)

 ENDIF

 CASE ( 5 )

 CALL clean(0, 22, 12, 22, 78)

 CALL CDIRECTORY

 CASE ( 6 )

 CALL clean(0, 22, 12, 22, 78)

 CASE ( 7 )

 CALL clean(0, 22, 12, 22, 78)

 CALL MKDIRECTORY

 CASE ( 8 ) 

 CALL clean(0, 22, 12, 22, 78)

 MORDAT=.FALSE.

 END SELECT

 GOTO 10

 ENDIF

 RETURN

 END
Appendix 1 117

C=========================================================================

 SUBROUTINE DPROJECT

C -------------------

 

C DISPLAY CURRENT PROJECT FILES

 

 CHARACTER*60 FILE(25), TEMP, PROJECT, DIRECTORY

 INTEGER*2 DYNLEN,I

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL mvprint(7, 10, 31,'PROJECT INFORMATION'C)

 CALL clean(0, 8, 35, 8,46)

 CALL mvprint(8, 10, 30,'CURRENT PROJECT : 'C)

 I=DYNLEN(PROJECT)

 TEMP=PROJECT

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 9, 35, 9,46)

 CALL mvprint(9, 10, 30,'PROJECT DIRECTORY : 'C)

 I=DYNLEN(DIRECTORY)

 TEMP=DIRECTORY

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL mvprint(10, 10, 31,'PROJECT FILES'C)

 CALL clean(0, 11, 35, 11, 46)

 CALL mvprint(11, 10, 30,'DSS DISCHARGE FILE : 'C)

 I=DYNLEN(FILE(12))

 TEMP=FILE(12)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 12, 35, 12, 46)

 CALL mvprint(12, 10, 30,'SEDIMENT INPUT FILE : 'C)

 I=DYNLEN(FILE(13))

 TEMP=FILE(13)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL clean(0, 13, 35, 13, 46)

 CALL mvprint(13, 10, 30,'DAILY LOAD OUTPUT FILE : 'C)

 I=DYNLEN(FILE(14))

 TEMP=FILE(14)

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 RETURN

 END

C============================================================================
118 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 SUBROUTINE FOPEN(ERROR,MSG)

C ----------------

C 

C OPEN INPUT AND OUTPUT FILES

C 

 CHARACTER*60 FILE(25),PROJECT,DIRECTORY,MSG

 LOGICAL EXIST,ERROR

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 

 ERROR=.FALSE.

 CALL FOPCHK(FILE(12),EXIST,MSG)

 IF(EXIST)THEN

 ERROR=.TRUE.

 ENDIF

 CALL FOPCHK(FILE(13),EXIST,MSG)

 IF(EXIST)THEN

 ERROR=.TRUE.

 ENDIF

 OPEN(11,FILE=FILE(13),STATUS='UNKNOWN')

 OPEN(12,FILE=FILE(14),STATUS='UNKNOWN')

 OPEN(13,FILE=FILE(12),STATUS='UNKNOWN')

 RETURN

 END

C==========================================================================

 SUBROUTINE LPROJECT

C -------------------

C LOAD PROJECT

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL settextposition(8, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 8, 35, 8, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(8, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 PROJECT=REC

 ENDIF

 call clean(0, 8, 35, 8, 46)
Appendix 1 119

 I=DYNLEN(PROJECT)

 IF(INDEX(PROJECT,'PRJ').EQ.0.AND.

 & INDEX(PROJECT,'.').EQ.0)THEN

 PROJECT(I+1:I+5)='.PRJ'

 I=I+5

 ENDIF

 TEMP=PROJECT

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL GETDEFAULTS('SKIP')

 CALL DPROJECT

 RETURN

 END

C==========================================================================

 SUBROUTINE SAVEDP

C -----------------

C CHANGE CURRENT PROJECT

 

 CHARACTER*60 FILE(25), PROJECT, DIRECTORY, REC*80

 CHARACTER DIR*60, CD*60

 CHARACTER MKDIR*60, PRJDIR*60

 INTEGER*2 I, J, DYNLEN

 CHARACTER*9 OPTMAX(5,7)

 LOGICAL MORDAT, EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /MAXOPT/ OPTMAX

 

 MORDAT=.TRUE.

 OPEN(10,FILE='\SEDIMENT\DEFAULT',STATUS='UNKNOWN')

 I=DYNLEN(PROJECT)

 J=DYNLEN(DIRECTORY)

 DO 5 K=1,J

 IF(DIRECTORY(K:K).NE.' ')THEN

 L=J-K+1

 GO TO 6

 ENDIF

5 CONTINUE

6 DIRECTORY(1:L)=DIRECTORY(K:J)

 DO 7 M=L+1,12

 DIRECTORY(M:M)=' '

7 CONTINUE

 WRITE(10,10)PROJECT(1:12)

10 FORMAT('C DEFAULT FILES FOR SEDIMENT SYSTEM',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F CURRENT PROJECT FILE : ',A12)

 CLOSE(10)
120 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 DIR='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=DIR,EXIST=EXIST)

 IF(EXIST)THEN

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 ELSE

 MKDIR='MKDIR \SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(MKDIR)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'CREATING DIRECTORY..'C)

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'CHANGING DIRECTORY..'C)

 ENDIF

 

 PRJDIR='\SEDIMENT\PROJECT\'//PROJECT(1:12)

 OPEN(10,FILE=PRJDIR,STATUS='UNKNOWN')

 WRITE(10,20)DIRECTORY

20 FORMAT('C',21X,'DEFAULT FILES FOR SEDIMENT SYSTEM',/,

 & 'C--------1---------2---------3---------4',/,

 & 'D PROJECT DIRECTORY : ',A60)

 WRITE(10,30)OPTMAX(1,1),OPTMAX(1,2),OPTMAX(1,3),

 & OPTMAX(1,4),OPTMAX(1,5),OPTMAX(1,6),

 & FILE(1),FILE(2),FILE(4),FILE(5),FILE(6),FILE(7)

30 FORMAT('C',12X,'DEFAULT FILES FOR SUSPENDED SEDIMENT'

 & ' ANALYSIS PROGRAM',/,

 & 'P HH007',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & 2A1,A3,3A1,/,

 & 'F SEDIMENT INPUT DATA : ',A60,/,

 & 'F DISCHARGE INPUT DATA : ',A60,/,

 & 'F 3 PAGE OUTPUT FILE : ',A60,/,

 & 'F HEIS OUTPUT FILE : ',A60,/,

 & 'F BED OUTPUT FILE : ',A60,/,

 & 'F SUMMARY DATA FILE : ',A60)

 WRITE(10,31)

 & OPTMAX(2,1),OPTMAX(2,2),OPTMAX(2,3),OPTMAX(2,4),

 & OPTMAX(2,5),OPTMAX(2,6),OPTMAX(2,7),FILE(8),FILE(9)

31 FORMAT('C',14X,'DEFAULT FILES FOR SEDIMENT',

 & ' RETRIEVAL PROGRAM',/,

 & 'P HH080',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & A2,1X,2(A5,1X),A6,1X,A6,2A2,/,

 & 'F DISCHARGE MASTER : ',A60,/, 

 & 'F DISCHARGE OUTPUT DATA : ',A60)
Appendix 1 121

 WRITE(10,32)

 & OPTMAX(3,1),OPTMAX(3,2),OPTMAX(3,3),OPTMAX(3,4),

 & OPTMAX(3,5),FILE(10),FILE(11)

32 FORMAT('C',23X,'HEIS DATA RETRIVAL PROGRAM',/,

 & 'P HH008',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : '

 & A1,1X,A5,1X,A6,1X,A6,A2,/, 

 & 'F HEIS INPUT FILE : ',A60,/,

 & 'F SEDIMENT OUTPUT FILE : ',A60)

 WRITE(10,33)FILE(12),FILE(13),FILE(14)

33 FORMAT('C',23X,'SEDIMENT CURVE FIT PROGRAM',/,

 & 'P HH048',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F DSS DISCHARGE INPUT : ',A60,/,

 & 'F SEDIMENT INPUT FILE : ',A60,/,

 & 'F DAILY LOAD DATA OUTPUT : ',A60)

 WRITE(10,34)FILE(15)

34 FORMAT('C',15X,'REGRESSION ANALYSIS FOR SEDIMENT',

 & ' RATING CURVE PROGRAM',/, 

 & 'P HH049',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT INPUT FILE : ',A60)

 WRITE(10,35)FILE(16),FILE(17)

35 FORMAT('C',14X,'REGESSION ANALYSIS FOR VARIOUS ',

 & ' GRAIN SIZES PROGRAM',/,

 & 'P HH079',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT DATA FILE : ',A60,/,

 & 'F GRAIN SIZE OUTPUT FILE : ',A60)

 WRITE(10,36)FILE(18),FILE(19)

36 FORMAT('C',14X,'MEDIAN OF VARIOUS GRAIN SIZES PROGRAM',/,

 & 'P HH050',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F SEDIMENT DATA FILE : ',A60,/,

 & 'F MEDIAN OF VARIOUS GRAIN: ',A60)

 WRITE(10,37)OPTMAX(4,1),OPTMAX(4,2),OPTMAX(4,3),

 & OPTMAX(4,4),OPTMAX(4,5),OPTMAX(4,6),FILE(20),FILE(21)

37 FORMAT('C',14X,'BED DATA RETRIVAL PROGRAM',/,

 & 'P HH082',/,

 & 'C--------1---------2---------3---------4',/,

 & 'O OPTIONS : ',

 & A1,1X,A1,2(1X,A5),2(1X,A6),/,

 & 'F HEIS INPUT FILE : ',A60,/

 & 'F EXTRACTED BED DATA : ',A60)

 WRITE(10,38)OPTMAX(5,1),OPTMAX(5,2),OPTMAX(5,3),

 & OPTMAX(5,4),FILE(22),FILE(23)

38 FORMAT('C',13X,'BED DATA TABULAR LISTING PROGRAM',/,
122 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 & 'P HH081',/,

 & 'C--------1---------2---------3---------4',/,

 & 'OPTION : ' 

 & A5,1X,A5,1X,A6,1X,A6,/,

 & 'F HEIS FILE : ',A60,/

 & 'F TABULAR BED DATA LIST : ',A60)

 WRITE(10,39)FILE(24),FILE(25)

39 FORMAT('C',14X,'BED MATERIAL PLOT PROGRAM',/,

 & 'P HH051',/,

 & 'C--------1---------2---------3---------4',/,

 & 'F EXTRACTED BED DATE : ',A60,/

 & 'F MASTER TITLE FILE : ',A60)

 CLOSE (10)

 RETURN

 END

C==========================================================================

 SUBROUTINE CPROJECT

C -------------------

C CREATE PROJECT

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 CHARACTER*9 OPTMAX(5,7)

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 COMMON /MAXOPT/ OPTMAX

 CALL settextposition(8, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 8, 35, 8, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(8, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 PROJECT=REC

 ENDIF

 call clean(0, 8, 35, 8, 46)

 I=DYNLEN(PROJECT)

 IF(INDEX(PROJECT,'PRJ').EQ.0)THEN

 PROJECT(I+1:I+5)='.PRJ'

 I=I+5

 ENDIF

 TEMP=PROJECT
Appendix 1 123

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 I=INDEX(PROJECT,'.')

 FILE(1)=PROJECT(1:I)//'SED'

 FILE(2)=PROJECT(1:I)//'DIS'

 FILE(4)=PROJECT(1:I)//'3PG'

 FILE(5)=PROJECT(1:I)//'HES'

 FILE(6)=PROJECT(1:I)//'BED'

 FILE(7)=PROJECT(1:I)//'SUM'

 FILE(8)='\SEDIMENT\MASTER\DISCHARG.MAS'

 FILE(9)=PROJECT(1:I)//'DIS'

 FILE(10)=PROJECT(1:I)//'HES'

 FILE(11)=PROJECT(1:I)//'SS1'

 FILE(12)=PROJECT(1:I)//'DSS'

 FILE(13)=PROJECT(1:I)//'SS1'

 FILE(14)=PROJECT(1:I)//'DLD'

 FILE(15)=PROJECT(1:I)//'SS1'

 FILE(16)=PROJECT(1:I)//'SS2'

 FILE(17)=PROJECT(1:I)//'SIZ'

 FILE(18)=PROJECT(1:I)//'SS2'

 FILE(19)=PROJECT(1:I)//'MED'

 FILE(20)=PROJECT(1:I)//'BED'

 FILE(21)=PROJECT(1:I)//'EBD'

 FILE(22)=PROJECT(1:I)//'BED'

 FILE(23)=PROJECT(1:I)//'LST'

 FILE(24)=PROJECT(1:I)//'EBD'

 FILE(25)='\SEDIMENT\MASTER\TITLE.MAS'

 OPTMAX(1,1)='*'

 OPTMAX(1,2)='N'

 OPTMAX(1,3)='YES'

 OPTMAX(1,4)='0'

 OPTMAX(1,5)='0'

 OPTMAX(1,6)='0'

 OPTMAX(2,1)='-4'

 OPTMAX(2,2)='03045'

 OPTMAX(2,3)='03045'

 OPTMAX(2,4)='900101'

 OPTMAX(2,5)='900430'

 OPTMAX(2,6)=' 0'

 OPTMAX(2,7)=' 0'

 OPTMAX(3,1)='1'

 OPTMAX(3,2)='03045'

 OPTMAX(3,3)='900101'

 OPTMAX(3,4)='900430'

 OPTMAX(3,5)='12'

 OPTMAX(4,1)='2'

 OPTMAX(4,2)='2'

 OPTMAX(4,3)='03045'

 OPTMAX(4,4)='03045'

 OPTMAX(4,5)='900101'

 OPTMAX(4,6)='900430'

 OPTMAX(5,1)='03045'

 OPTMAX(5,2)='03045'
124 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

 OPTMAX(5,3)='900101'

 OPTMAX(5,4)='900430'

 CALL DPROJECT

 RETURN

 END

C==========================================================================

 

 SUBROUTINE CDIRECTORY

C -------------------

C CHANGE DIRECTORY'S NAME

 INCLUDE 'FMENUS.REC'

 INCLUDE 'FGRAPH.FD'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 RECORD /rccoord/ curpos

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL settextposition(9, 35, curpos)

 dummy4 = setbkcolor( 0 )

 call clean(0, 9, 35, 9, 46)

 dummy4 = setbkcolor( 1 )

 CALL settextposition(9, 35, curpos)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 DIRECTORY=REC

 ENDIF

 call clean(0, 9, 35, 9, 46)

 I=DYNLEN(DIRECTORY)

 TEMP=DIRECTORY

 TEMP(I+1:I+1)=CHAR(0)

 CALL mvprint(0, 0, 14, TEMP)

 CALL CHDIRECTORY

 RETURN

 END

C=========================================================================

 SUBROUTINE CHDIRECTORY

C ----------------------

C CHANGE DIRECTORY 

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY
Appendix 1 125

 CHARACTER CD*60, DIR*60

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 I=DYNLEN(DIRECTORY)

 DIR='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=DIR,EXIST=EXIST)

 IF(EXIST)THEN

 CD='CD\SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 CALL SYSTEM(CD)

 ELSE

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DIRECTORY DOES NOT EXIST..'C)

 ENDIF

 RETURN

 END

C=========================================================================

 SUBROUTINE MKDIRECTORY

C ----------------------

C MAKE DIRECTORY 

 INCLUDE 'FGRAPH.FD'

 INCLUDE 'FMENUS.REC'

 CHARACTER*60 FILE(25), PROJECT, TEMP, DIRECTORY

 CHARACTER MKDIR*60, MD*60

 INTEGER*2 DYNLEN,I

 INTEGER*4 dummy4

 LOGICAL EXIST

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 I=DYNLEN(DIRECTORY)

 MKDIR='MKDIR \SEDIMENT\'//DIRECTORY(1:I)//CHAR(0)

 MD='\SEDIMENT\'//DIRECTORY(1:I)

 INQUIRE(FILE=MD,EXIST=EXIST)

 IF(EXIST)THEN

 CALL clean(0, 22, 12, 22, 78)

 CALL mvprint(22 , 12, 14,'DIRECTORY ALREADY EXIST..'C)

 ELSE

 CALL SYSTEM(MKDIR)

 ENDIF

 RETURN

 END
126 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

C=========================================================================

 SUBROUTINE CFILES

C -----------------

 

C CHANGE PROJECT FILES

 CHARACTER*60 FILE(25), TEMP, PROJECT, DIRECTORY, REC

 INTEGER*2 DYNLEN,I

 COMMON /FILENAME/ FILE, PROJECT, DIRECTORY

 CALL clean(142, 11, 35, 11, 46)

 CALL mvprint(11, 10, 30,'DSS DISCHARGE FILE : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(12)=REC

 ENDIF

 I=DYNLEN(FILE(12))

 TEMP=FILE(12)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 11, 35, 11, 46)

 CALL mvprint(11, 35, 14, TEMP)

 CALL clean(142, 12, 35, 12, 46)

 CALL mvprint(12, 10, 30,'SEDIMENT INPUT FILE : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(13)=REC

 ENDIF

 I=DYNLEN(FILE(13))

 TEMP=FILE(13)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 12, 35, 12, 46)

 CALL mvprint(12, 35, 14, TEMP)

 CALL clean(142, 13, 35, 13, 46)

 CALL mvprint(13, 10, 30,'DAILY LOAD OUTPUT FILE : 'C)

 READ(*,'(A60)')REC

 IF(REC.NE.' ')THEN

 FILE(14)=REC

 ENDIF

 I=DYNLEN(FILE(14))

 TEMP=FILE(14)

 TEMP(I+1:I+1)=CHAR(0)

 CALL clean(0, 13, 35, 13, 46)

 CALL mvprint(13, 35, 14, TEMP)

 RETURN

 END
Appendix 2.

Example laboratory data sheet used for recording laboratory results for a cooperative program 

between the U.S. Geological Survey and the U.S. Army Corps of Engineers in the lower 

Mississippi-Atchafalaya River Basin from 1973 to 2001, which also served as the basis for the 

Excel spreadsheet that was used from 2001 to February 2015



Appendix 3 131

Appendix 3.

Example 80-column text file (SED file) used as input to the U.S. Army Corps of Engineers 

(USACE) FORTRAN modules that computed suspended-sediment concentration, particle-size 

distribution, and suspended-sediment discharge for a cooperative program between the U.S. 

Geological Survey and the USACE in the lower Mississippi-Atchafalaya River Basin from 1973 to 

February 2015

0 3 0 4 5 A T C H A F A L A Y A R I V E R @ S I M M E S P O R T

1 2 0 8 9 8 1 5 2 1 1 0 0 1 2 0 0 P - 6 3 A - P 3 3 2 9 0 1 0 0 1 8 8

4 8 7 4 7 2 4 4 9 4 2 3 3 7 6 2 9 0 2 6 9 2 3 5 2 0 1 9 

1 2 4 5 5 1 2 0 

1 0 0 0 1 0 0 0 1 0 0 0 1 0 0 0 9 8 3 9 7 6 9 4 6 9 0 6 8 9 6 5 6 7 1 5 1 4 1 1 0 0 5 0 4 0 4 0 4 0 0

1 5 4 5 2 4 1 6 4 8 5 2 1 5 0 9 1 2 0 0 2 4 1 

1 5 5 3 1 9 3 1 4 2 7 4 1 5 1 2 0 0 2 4 

1 5 6 5 4 1 6 4 2 4 5 1 4 1 9 1 2 0 0 2 4 

1 5 7 6 8 7 3 4 5 2 5 0 8 5 1 3 1 6 0 0 3 3 1 

1 5 8 8 8 3 4 2 6 8 5 6 4 6 0 2 1 6 0 0 3 3 2 

1 5 9 9 3 8 5 4 8 7 4 2 4 3 8 3 1 6 0 0 3 3 2 

1 6 0 9 7 6 5 2 8 8 4 9 6 4 8 1 2 0 0 0 3 7 1 

1 6 1 2 0 6 9 1 4 2 1 9 6 7 1 0 7 0 8 2 0 0 0 3 7 2 

1 6 2 4 6 4 6 1 2 9 4 0 9 4 5 7 4 2 1 3 5 7 2 0 0 0 3 7 3 3 

 135

Appendix 4.

Corrected and original results for instantaneous stream discharge, suspended-sediment 

concentration, suspended-sediment percent smaller than 0.0625 millimeter, and suspendedsediment discharge for water samples collected from selected sites in the lower MississippiAtchafalaya River Basin. Data in this appendix are publicly available in a data release by Norton 

and others (2019)

Appendix 4 137

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/02/1989 13:00 CDT 136,000 233 83 85,600 136,000 225 86 82,600 

10/18/1989 12:00 CDT 111,000 — — — 111,000 164 59 49,200 

11/17/1989 09:45 CST 88,000 117 87 27,900 88,000 149 94 35,400 

11/30/1989 10:00 CST 150,000 236 50 95,600 — — — — 

12/13/1989 10:00 CST 97,000 102 70 26,800 97,000 103 72 27,000 

12/20/1989 11:00 CST 91,000 76 77 18,600 91,000 94 87 23,100 

01/11/1990 13:00 CST 103,000 290 89 80,500 103,000 326 92 90,800 

01/31/1990 10:00 CST 60,300 192 99 31,300 60,000 150 100 24,200 

02/08/1990 12:30 CST 101,000 244 99 66,500 101,000 244 100 66,600 

02/23/1990 12:00 CST 253,000 150 56 103,000 253,000 197 68 134,000 

03/13/1990 14:30 CST 213,000 115 86 66,000 213,000 137 90 78,600 

03/27/1990 11:30 CST 190,000 243 94 125,000 190,000 242 95 124,000 

04/12/1990 12:00 CDT 111,000 111 83 33,200 111,000 134 90 40,000 

04/25/1990 12:00 CDT 121,000 118 96 38,400 121,000 146 98 47,500 

05/09/1990 12:00 CDT 141,000 — — — 141,000 215 94 81,700 

05/25/1990 11:30 CDT 177,000 198 85 94,400 177,000 250 84 120,000 

06/12/1990 11:30 CDT 278,000 107 89 80,200 278,000 127 94 95,100 

06/22/1990 11:30 CDT 226,000 203 99 124,000 226,000 238 99 145,000 

07/12/1990 11:30 CDT 144,000 299 94 116,000 144,000 354 95 138,000 

07/25/1990 12:00 CDT 163,000 184 75 81,000 125,000 218 84 73,600 

08/10/1990 12:00 CDT 117,000 194 75 61,200 117,000 236 82 74,500 

08/28/1990 12:35 CDT 102,000 130 64 35,700 102,000 145 67 40,000 

09/12/1990 09:30 CDT 107,000 152 69 43,900 107,000 204 65 59,000 

09/24/1990 09:45 CDT 93,200 129 67 32,400 93,000 151 77 38,000 

10/10/1990 10:15 CDT 76,700 173 83 35,800 77,000 179 85 37,300 

10/24/1990 12:00 CDT 90,100 98 85 23,900 90,000 114 91 27,600 

11/19/1990 11:50 CST 76,800 73 86 15,100 77,000 88 90 18,300 

12/05/1990 10:10 CST 83,400 246 94 55,400 — — — — 

12/21/1990 09:10 CST 124,000 144 87 48,200 113,000 161 84 49,300 
138 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/14/1991 11:30 CST 334,000 186 67 168,000 334,000 208 73 188,000 

01/25/1991 11:25 CST 360,000 93 74 90,200 360,000 119 81 116,000 

01/30/1991 11:45 CST 340,000 96 71 88,500 340,000 117 77 108,000 

02/07/1991 10:50 CST 207,000 124 86 69,300 207,000 141 89 79,000 

02/14/1991 10:40 CST 140,000 115 88 43,300 140,000 151 92 57,000 

02/21/1991 10:35 CST 196,000 155 73 82,000 196,000 218 72 115,000 

02/28/1991 10:20 CST 221,000 147 78 87,600 221,000 167 82 99,000 

03/07/1991 10:05 CST 234,000 103 70 65,000 234,000 132 79 84,000 

03/14/1991 10:35 CST 258,000 107 66 74,300 258,000 125 74 87,000 

03/21/1991 09:50 CST 194,000 135 81 70,500 194,000 158 86 83,000 

03/29/1991 10:15 CST 206,000 187 75 104,000 206,000 209 81 116,000 

04/04/1991 10:13 CST 223,000 184 78 111,000 223,000 209 83 126,000 

04/11/1991 10:50 CDT 281,000 171 67 130,000 281,000 192 74 146,000 

04/18/1991 11:00 CDT 201,000 146 88 79,100 201,000 159 91 86,000 

04/25/1991 12:30 CDT 188,000 87 95 44,000 188,000 118 98 60,000 

05/03/1991 12:45 CDT 220,000 135 94 80,400 220,000 169 95 100,000 

05/09/1991 12:25 CDT 144,000 112 94 43,600 144,000 145 95 56,000 

05/30/1991 13:20 CDT 129,000 131 95 45,500 129,000 169 97 59,000 

06/06/1991 11:15 CDT 138,000 177 95 66,100 — — — — 

06/13/1991 11:45 CDT 142,000 185 96 70,900 142,000 189 97 73,000 

06/18/1991 12:10 CDT 96,000 232 98 60,200 — — — — 

06/27/1991 11:10 CDT 78,600 248 99 52,500 — — — — 

07/03/1991 11:30 CDT 91,400 302 99 74,600 — — — — 

07/11/1991 11:50 CDT 89,700 176 91 42,500 — — — — 

07/25/1991 10:20 CDT 112,000 191 70 57,800 — — — — 

08/09/1991 12:35 CDT 68,100 56 80 10,400 68,000 75 90 14,000 

08/22/1991 10:55 CDT 62,400 — — — — — — — 

09/13/1991 10:35 CDT 45,500 50 92 6,120 45,000 70 94 8,500 

09/27/1991 11:55 CDT 43,600 41 92 4,830 42,000 49 96 5,500 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 139

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/11/1991 10:30 CDT 42,600 43 93 4,900 43,000 40 92 4,600 

10/24/1991 10:55 CDT 44,600 — — — 45,000 72 89 8,700 

11/08/1991 11:00 CST 38,200 109 96 11,300 38,000 151 98 16,000 

11/21/1991 11:40 CST 60,000 314 98 50,900 60,000 99 99 59,000 

12/05/1991 10:45 CST 84,600 — — — 85,000 284 97 65,000 

12/19/1991 11:00 CST 185,000 — — — 185,000 266 84 133,000 

01/02/1992 12:50 CST 118,000 106 93 33,800 118,000 110 96 35,100 

01/10/1992 10:10 CST 111,000 108 93 32,300 111,000 102 94 30,400 

01/16/1992 11:25 CST 110,000 — — — 110,000 121 93 35,900 

01/23/1992 10:15 CST 80,600 82 96 17,800 81,000 104 98 22,600 

01/30/1992 13:15 CST 42,000 56 98 6,380 42,000 99 99 11,200 

02/06/1992 09:45 CST 88,500 327 97 78,000 89,000 371 98 89,100 

02/14/1992 12:15 CST 37,600 141 97 14,300 38,000 190 98 19,500 

02/20/1992 10:05 CST 12,200 25 71 811 12,000 41 91 1,330 

02/27/1992 10:30 CST 64,800 128 95 22,400 65,000 151 97 26,500 

03/06/1992 11:05 CST 94,200 250 95 63,600 94,000 252 96 63,900 

03/12/1992 11:20 CST 87,200 120 89 28,100 87,000 127 92 29,800 

03/20/1992 09:55 CST 138,000 194 86 72,300 138,000 188 88 70,100 

03/26/1992 10:40 CST 162,000 209 82 91,300 162,000 217 85 95,100 

04/03/1992 10:30 CST 191,000 — — — 191,000 253 86 130,000 

04/09/1992 10:40 CDT 166,000 177 74 79,500 166,000 198 78 88,500 

04/23/1992 10:30 CDT 99,600 99 85 26,500 100,000 100 90 27,000 

05/01/1992 10:40 CDT 182,000 — — — 182,000 254 80 125,000 

05/06/1992 10:25 CDT 205,000 373 85 207,000 205,000 365 88 202,000 

05/15/1992 10:55 CDT 167,000 178 70 80,100 167,000 209 75 94,200 

05/21/1992 10:40 CDT 133,000 107 70 38,500 133,000 120 76 42,900 

05/28/1992 12:50 CDT 96,200 78 85 20,200 96,000 93 90 24,000 

06/04/1992 10:40 CDT 72,200 61 95 12,000 72,000 87 95 16,800 

06/11/1992 11:20 CDT 81,200 176 98 38,500 81,000 188 100 41,100 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
140 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

06/17/1992 10:20 CDT 76,300 139 96 28,600 76,000 158 97 32,400 

06/26/1992 10:30 CDT 79,000 85 95 18,200 79,000 107 97 22,700 

07/10/1992 10:30 CDT 61,600 88 99 14,600 61,000 117 100 19,200 

07/23/1992 10:00 CDT 103,000 93 91 25,900 103,000 108 94 29,900 

08/21/1992 10:45 CDT 161,000 204 93 88,500 161,000 211 93 91,600 

10/27/1992 08:00 CST 88,800 — — — 89,000 125 78 30,000 

11/10/1992 11:30 CST 83,400 139 75 31,300 83,000 134 86 30,100 

11/24/1992 11:30 CST 172,000 210 82 97,400 172,000 238 85 111,000 

12/08/1992 12:00 CST 286,000 474 56 366,000 286,000 404 58 312,000 

12/31/1992 10:45 CST 215,000 286 83 166,000 215,000 316 85 183,000 

01/12/1993 14:30 CST 209,000 211 71 119,000 209,000 214 73 121,000 

01/26/1993 10:00 CST 221,000 133 81 79,400 221,000 160 76 96,000 

02/17/1993 11:00 CST 162,000 164 65 71,900 162,000 208 76 91,000 

03/11/1993 13:00 CST 185,000 177 83 88,300 185,000 196 87 98,000 

03/23/1993 13:30 CST 281,000 258 65 196,000 — — — — 

04/06/1993 09:30 CDT 270,000 192 67 140,000 — — — — 

04/20/1993 10:30 CDT 331,000 137 58 122,000 — — — — 

05/04/1993 10:30 CDT 314,000 102 68 86,200 314,000 128 75 109,000 

06/02/1993 14:00 CDT 297,000 — — — 297,000 168 91 134,000 

06/22/1993 13:00 CDT 214,000 — — — 214,000 340 91 196,000 

06/29/1993 09:00 CDT 166,000 139 92 62,100 — — — — 

07/14/1993 15:00 CDT 233,000 386 79 243,000 233,000 448 83 282,000 

07/27/1993 15:30 CDT 325,000 247 76 217,000 325,000 303 78 266,000 

08/10/1993 10:30 CDT 322,000 316 63 275,000 322,000 354 66 308,000 

08/24/1993 11:00 CDT 315,000 220 55 187,000 314,000 239 56 203,000 

09/08/1993 11:30 CDT 190,000 246 80 126,000 190,000 237 78 121,000 

09/21/1993 13:30 CDT 194,000 184 83 96,200 194,000 197 83 103,000 

10/05/1993 14:30 CDT 265,000 289 76 207,000 265,000 371 62 266,000 

10/19/1993 12:00 CDT 211,000 137 77 78,100 211,000 171 85 97,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 141

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/16/1993 11:30 CST 104,000 417 98 117,000 104,000 464 98 130,000 

11/30/1993 14:00 CST 281,000 288 62 219,000 281,000 339 68 257,000 

12/06/1993 11:30 CST 250,000 162 72 110,000 250,000 177 75 120,000 

12/20/1993 15:00 CST 247,000 — — — 247,000 171 78 114,000 

01/31/1994 13:00 CST 83,000 275 92 61,700 83,000 294 93 66,000 

02/14/1994 11:00 CST 235,000 235 79 149,000 235,000 242 76 153,000 

03/14/1994 08:00 CST 277,000 132 69 99,000 277,000 141 69 105,000 

03/28/1994 14:00 CST 307,000 122 54 101,000 307,000 152 64 126,000 

04/11/1994 14:30 CDT 288,000 86 65 66,500 288,000 93 70 72,000 

04/25/1994 14:00 CDT 370,000 193 52 193,000 370,000 186 54 186,000 

05/03/1994 11:30 CDT 414,000 189 29 211,000 414,000 207 33 231,000 

05/17/1994 13:30 CDT 339,000 76 78 69,300 339,000 88 80 80,000 

06/01/1994 13:30 CDT 211,000 160 89 90,900 211,000 196 90 112,000 

06/14/1994 13:30 CDT 122,000 109 96 36,000 122,000 129 97 42,000 

06/28/1994 11:30 CDT 133,000 122 87 43,800 122,000 173 91 57,000 

07/12/1994 12:00 CDT 154,000 — — — 154,000 386 95 161,000 

07/26/1994 13:30 CDT 104,000 140 92 39,300 104,000 214 94 60,000 

08/09/1994 11:30 CDT 116,000 113 67 35,200 116,000 176 81 55,000 

08/23/1994 12:00 CDT 80,000 63 84 13,500 — — — — 

09/07/1994 14:00 CDT 92,000 50 82 12,400 77,000 78 86 16,000 

10/04/1994 13:00 CDT 68,000 43 78 7,800 — — — — 

10/18/1994 14:00 CDT 44,000 35 97 4,150 44,000 78 99 9,300 

11/01/1994 12:00 CST 50,000 67 92 9,000 — — — — 

11/16/1994 14:00 CST 72,000 211 95 41,100 72,000 213 96 41,000 

11/29/1994 10:00 CST 73,000 199 97 39,300 — — — — 

12/13/1994 13:00 CST 141,000 147 80 56,000 141,000 171 82 65,000 

01/31/1995 12:00 CST 155,000 — — — — — — — 

02/14/1995 13:45 CST 134,000 113 80 40,900 134,000 163 88 59,000 

02/28/1995 12:00 CST 175,000 225 66 106,000 — — — — 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
142 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/14/1995 13:30 CST 110,000 — — — 110,000 237 98 70,300 

04/04/1995 13:30 CDT 109,000 — — — 109,000 200 88 58,700 

04/18/1995 13:00 CDT 64,000 119 97 20,600 64,000 258 97 44,700 

05/02/1995 11:00 CDT 107,000 170 91 49,100 — — — — 

05/23/1995 13:00 CDT 185,000 225 91 112,000 185,000 293 95 146,000 

06/13/1995 13:00 CDT 462,000 173 46 215,000 — — — — 

06/27/1995 13:00 CDT 376,000 107 62 109,000 — — — — 

07/25/1995 13:00 CDT 159,000 256 82 110,000 — — — — 

08/08/1995 14:00 CDT 116,000 123 82 38,400 116,000 146 84 45,700 

08/29/1995 12:00 CDT 129,000 115 76 39,900 — — — — 

09/27/1995 14:00 CDT 71,000 60 82 11,500 71,000 127 95 24,300 

10/24/1995 12:00 CDT 93,000 94 72 23,500 — — — — 

11/07/1995 12:00 CST 88,000 74 87 17,600 — — — — 

12/12/1995 11:30 CST 105,000 61 64 17,100 — — — — 

01/09/1996 11:00 CST 90,000 160 81 38,800 — — — — 

02/13/1996 13:00 CST 271,000 254 54 186,000 — — — — 

03/06/1996 11:00 CST 172,000 131 74 60,900 — — — — 

03/27/1996 11:00 CST 207,000 — — — — — — — 

04/09/1996 10:45 CDT 277,000 170 61 127,000 277,000 207 67 155,000 

04/12/1996 10:00 CDT 278,000 185 63 139,000 278,000 222 68 167,000 

04/19/1996 10:00 CDT 189,000 156 91 79,500 189,000 176 93 89,900 

05/14/1996 10:00 CDT 321,000 205 73 177,000 — — — — 

06/05/1996 09:00 CDT 395,000 118 55 126,000 — — — — 

07/16/1996 09:00 CDT 149,000 103 99 41,400 — — — — 

07/30/1996 11:30 CDT 149,000 118 85 47,500 — — — — 

08/13/1996 11:00 CDT 137,000 111 92 41,100 — — — — 

09/10/1996 12:00 CDT 83,000 76 95 17,100 — — — — 

10/01/1996 11:00 CDT 79,000 113 96 24,100 — — — — 

10/24/1996 09:00 CDT 68,000 58 94 10,600 — — — — 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 143

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/19/1996 12:30 CST 168,000 187 91 84,700 — — — — 

12/10/1996 12:00 CST 224,000 239 82 145,000 — — — — 

01/22/1997 12:00 CST 143,000 115 84 44,300 — — — — 

02/04/1997 12:00 CST 190,000 294 79 151,000 — — — — 

02/25/1997 10:00 CST 134,000 141 79 51,000 — — — — 

04/01/1997 10:15 CST 411,000 96 54 107,000 411,000 218 58 242,000 

04/22/1997 11:00 CDT 228,000 97 94 59,500 228,000 185 98 114,000 

05/06/1997 10:00 CDT 141,000 120 96 45,500 141,000 226 81 86,000 

05/20/1997 12:00 CDT 165,000 155 97 68,900 165,000 211 99 94,000 

06/10/1997 11:00 CDT 235,000 256 85 162,000 235,000 399 92 253,000 

07/01/1997 12:00 CDT 285,000 146 76 113,000 — — — — 

07/15/1997 12:00 CDT 190,000 216 78 111,000 — — — — 

08/12/1997 12:00 CDT 93,000 46 95 11,600 — — — — 

08/26/1997 11:30 CDT 114,000 68 87 20,900 — — — — 

09/23/1997 11:00 CDT 80,900 49 85 10,700 — — — — 

10/16/1997 12:00 CDT 71,000 67 91 12,900 — — — — 

11/04/1997 11:00 CST 82,000 81 95 17,800 73,000 133 98 26,200 

12/09/1997 11:00 CST 76,400 45 99 9,230 77,000 122 100 25,300 

01/13/1998 13:30 CST 56,000 — — — 56,000 273 100 41,000 

02/05/1998 09:30 CST 81,700 110 98 24,300 82,000 170 100 38,000 

02/24/1998 09:00 CST 181,000 247 85 121,000 181,000 318 86 155,000 

03/17/1998 12:00 CST 171,000 143 87 66,000 171,000 212 92 98,000 

04/07/1998 09:00 CDT 254,000 158 73 108,000 254,000 223 82 153,000 

05/19/1998 11:00 CDT 413,000 156 38 174,000 413,000 192 49 214,000 

06/24/1998 12:00 CDT 267,000 265 82 191,000 268,000 304 85 220,000 

08/18/1998 11:00 CDT 155,000 160 85 66,900 1,550,000 251 91 105,000 

11/17/1998 12:00 CST 136,000 297 96 109,000 136,000 354 97 130,000 

12/08/1998 08:00 CST 106,000 131 89 37,600 106,000 324 61 93,000 

12/22/1998 10:30 CST 83,400 — — — 83,000 461 99 103,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
144 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/13/1999 12:00 CST 70,200 — — — 70,000 543 100 103,000 

01/26/1999 10:30 CST 169,000 — — — 169,000 599 94 273,000 

02/09/1999 12:00 CST 259,000 206 85 144,000 259,000 227 88 159,000 

02/23/1999 10:00 CST 317,000 179 71 153,000 317,000 293 55 251,000 

03/09/1999 10:30 CST 177,000 127 86 60,600 177,000 203 93 97,000 

03/30/1999 10:30 CST 284,000 129 65 98,900 12,840,000 181 73 11,390,000 

04/14/1999 12:00 CDT 120,000 118 100 38,100 120,000 171 100 55,500 

04/21/1999 11:00 CDT 160,000 135 74 58,400 160,000 185 74 79,800 

05/19/1999 14:00 CDT 328,000 197 77 174,000 328,000 263 83 233,000 

05/25/1999 12:00 CDT 293,000 161 77 127,000 293,000 247 85 195,000 

07/07/1999 11:30 CDT 204,000 188 91 103,000 204,000 312 95 172,000 

07/27/1999 11:15 CDT 160,000 195 90 84,000 160,000 271 92 117,000 

08/10/1999 09:30 CDT 126,000 94 87 31,900 126,000 189 94 64,300 

09/21/1999 11:00 CDT 50,700 53 92 7,190 50,700 93 97 13,000 

10/07/1999 11:00 CDT 45,000 42 95 5,130 44,955 95 99 11,500 

11/02/1999 11:00 CST 49,600 57 100 7,590 49,600 138 100 18,500 

12/07/1999 11:00 CST 61,300 55 88 9,170 61,300 101 94 16,700 

12/28/1999 10:00 CST 122,000 91 71 30,000 122,000 124 78 40,600 

01/11/2000 11:00 CST 80,400 81 88 17,700 80,400 122 92 26,500 

01/25/2000 11:30 CST 83,400 — — — 83,400 348 97 78,300 

02/08/2000 12:00 CST 59,100 — — — 59,100 201 95 32,000 

02/29/2000 11:00 CST 205,000 569 79 315,000 205,000 686 76 379,000 

03/14/2000 12:00 CST 195,000 208 69 110,000 195,000 246 74 130,000 

03/28/2000 11:00 CST 167,000 175 75 79,000 167,000 216 81 97,000 

04/11/2000 12:00 CDT 95,500 132 99 34,000 95,500 206 100 53,000 

04/25/2000 12:00 CDT 174,000 139 83 65,200 174,000 180 87 84,700 

05/09/2000 11:30 CDT 132,000 86 94 30,700 132,000 134 96 47,800 

05/23/2000 11:00 CDT 75,200 159 99 32,400 75,200 217 99 44,000 

06/13/2000 12:00 CDT 119,000 96 94 30,800 119,000 143 96 46,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 145

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/18/2000 11:00 CDT 152,000 153 88 62,800 152,000 184 90 75,200 

08/01/2000 12:30 CDT 122,000 119 85 39,200 122,000 151 88 49,700 

09/26/2000 10:00 CDT 64,400 311 98 54,100 64,400 390 99 67,800 

10/17/2000 11:00 CDT 79,500 61 88 13,100 79,500 96 93 20,600 

11/14/2000 10:30 CST 27,800 58 99 4,350 27,800 128 100 9,610 

12/05/2000 11:30 CST 36,400 75 91 7,340 36,400 164 98 16,100 

12/19/2000 11:00 CST 23,500 46 97 2,930 23,500 90 97 5,700 

01/04/2001 12:00 CST 18,300 66 100 3,280 18,300 101 98 5,000 

01/23/2001 11:00 CST 7,020 71 99 1,340 7,020 137 99 2,600 

02/06/2001 11:00 CST 51,900 105 97 14,700 51,900 177 99 24,800 

02/27/2001 11:00 CST 166,000 270 88 121,000 166,000 304 88 136,000 

03/16/2001 12:00 CST 132,000 151 97 53,800 132,000 202 98 71,800 

03/27/2001 11:00 CST 65,600 64 100 11,200 65,600 118 100 20,800 

04/10/2001 11:00 CDT 87,800 112 100 26,400 87,800 141 98 33,500 

04/24/2001 10:00 CDT 151,000 302 95 123,000 151,000 341 97 139,000 

05/08/2001 11:30 CDT 162,000 161 94 70,500 162,000 249 98 109,000 

05/22/2001 11:00 CDT 137,000 240 92 88,900 137,000 310 95 115,000 

06/12/2001 11:00 CDT 164,000 135 94 59,900 164,000 199 96 87,800 

07/10/2001 11:30 CDT 132,000 216 94 77,100 132,000 270 96 96,500 

08/21/2001 09:30 CDT 91,100 — — — 91,100 128 95 31,400 

09/11/2001 10:00 CDT 64,600 120 97 20,900 64,600 159 98 27,800 

10/02/2001 10:00 CDT 69,900 68 91 12,900 69,900 116 95 21,900 

11/27/2001 11:00 CST 65,200 75 99 13,300 65,200 132 99 23,200 

12/07/2001 12:00 CST 165,000 411 97 183,000 165,000 488 97 217,000 

12/18/2001 12:00 CST 114,000 169 96 52,100 114,000 218 97 67,200 

01/15/2002 11:30 CST 36,500 57 99 5,570 36,500 88 99 8,660 

01/29/2002 15:00 CST 62,600 141 100 23,800 62,600 198 100 33,400 

02/12/2002 12:00 CST 245,000 216 83 143,000 245,000 253 86 168,000 

02/27/2002 11:00 CST 109,000 103 98 30,400 109,000 145 99 42,500 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
146 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/12/2002 11:00 CST 108,000 — — — 108,000 116 96 33,800 

03/26/2002 10:00 CST 182,000 304 96 150,000 182,000 357 94 175,000 

04/12/2002 11:30 CDT 272,000 99 80 73,000 272,000 125 84 91,900 

04/30/2002 10:00 CDT 147,000 112 97 44,400 147,000 138 98 54,900 

05/14/2002 11:00 CDT 288,000 175 83 136,000 288,000 206 86 160,000 

05/21/2002 09:30 CDT 336,000 196 75 178,000 336,000 216 78 196,000 

06/11/2002 11:15 CDT 333,000 93 58 83,900 333,000 102 84 91,800 

07/09/2002 15:30 CDT 129,000 — — — 129,000 183 88 56,100 

07/10/2002 11:30 CDT 120,000 309 95 100,000 — — — — 

08/14/2002 11:00 CDT 82,000 154 85 34,200 92,800 187 88 46,800 

09/17/2002 11:00 CDT 66,000 67 88 11,900 78,500 176 96 37,400 

10/08/2002 10:30 CDT 122,000 149 89 49,100 122,000 182 91 60,100 

11/13/2002 09:30 CST 67,000 93 97 16,800 73,900 264 100 52,700 

12/03/2002 09:30 CST 117,000 105 54 33,300 133,000 194 75 69,600 

12/17/2002 10:00 CST 63,000 57 91 9,660 77,900 155 98 32,500 

01/14/2003 11:45 CST 162,000 121 87 52,700 162,000 179 90 78,500 

01/28/2003 10:30 CST 79,000 98 90 20,800 79,000 153 94 32,700 

02/11/2003 11:30 CST 63,300 144 97 24,500 63,300 281 100 48,000 

02/25/2003 10:00 CST 160,000 271 91 117,000 160,000 345 91 149,000 

03/10/2003 12:15 CST 305,000 233 69 191,000 305,000 273 74 225,000 

03/25/2003 11:00 CST 160,000 101 85 43,700 160,000 170 91 73,300 

04/08/2003 11:30 CST 141,000 129 89 49,200 141,000 212 94 81,000 

04/22/2003 09:30 CST 192,000 196 65 102,000 192,000 258 74 133,000 

05/16/2003 10:45 CST 270,000 271 83 197,000 270,000 325 86 237,000 

05/28/2003 10:00 CST 398,000 187 48 201,000 398,000 253 49 272,000 

06/10/2003 09:30 CST 285,000 124 71 95,000 285,000 187 76 144,000 

07/15/2003 10:00 CST 91,900 70 92 17,300 91,900 155 98 38,400 

08/12/2003 10:00 CST 144,000 82 81 32,100 144,000 155 91 60,300 

09/30/2003 10:00 CDT 99,800 71 81 19,000 99,800 129 89 34,700 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 147

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/28/2003 09:30 CST 93,300 78 68 19,600 93,300 146 83 36,800 

11/25/2003 11:00 CST 153,000 132 84 54,400 153,000 183 88 75,700 

12/09/2003 10:00 CST 240,000 — — — 240,000 345 62 223,000 

12/23/2003 11:30 CST 189,000 166 53 84,700 189,000 212 63 108,000 

01/24/2004 10:00 CST 258,000 211 62 147,000 258,000 278 71 194,000 

01/27/2004 10:00 CST 179,000 120 91 57,800 179,000 158 93 76,400 

02/20/2004 10:00 CST 211,000 160 89 91,200 211,000 204 91 116,000 

02/27/2004 10:00 CST 174,000 106 95 49,700 174,000 173 98 81,100 

03/09/2004 09:45 CST 102,000 115 97 31,700 102,000 173 99 47,900 

03/23/2004 09:30 CST 314,000 252 68 214,000 314,000 306 74 260,000 

04/27/2004 10:00 CST 197,000 152 78 80,700 197,000 231 86 123,000 

05/18/2004 10:00 CST 172,000 146 96 67,900 172,000 200 97 92,900 

06/29/2004 10:00 CST 190,000 224 98 115,000 190,000 294 99 151,000 

08/17/2004 11:00 CST 127,000 70 76 24,000 127,000 144 89 49,400 

09/21/2004 12:00 CST 123,000 117 84 38,900 123,000 175 89 57,800 

10/13/2004 11:00 CST 84,600 125 99 28,600 84,600 181 100 41,400 

11/30/2004 11:00 CST 113,000 151 98 45,900 113,000 199 99 60,600 

12/07/2004 11:00 CST 163,000 181 90 79,800 163,000 235 90 103,000 

12/21/2004 09:45 CST 292,000 150 67 118,000 292,000 194 75 153,000 

01/04/2005 10:00 CST 175,000 87 80 41,100 175,000 126 86 59,500 

01/25/2005 10:00 CST 396,000 184 53 197,000 396,000 242 59 259,000 

02/09/2005 10:30 CST 347,000 80 69 75,200 347,000 132 82 123,000 

02/23/2005 13:00 CST 195,000 108 84 56,800 195,000 171 90 90,000 

03/08/2005 11:00 CST 261,000 105 69 74,100 261,000 154 79 108,000 

03/22/2005 11:00 CST 198,000 120 50 64,400 198,000 191 67 102,000 

04/12/2005 11:00 CST 230,000 186 84 115,000 205,000 247 88 137,000 

05/04/2005 11:30 CST 175,000 146 61 68,800 175,000 195 71 92,500 

05/17/2005 11:00 CDT 171,000 130 69 60,200 171,000 192 79 88,700 

06/07/2005 11:30 CDT 126,000 142 96 48,300 126,000 206 97 69,700 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
148 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/12/2005 11:00 CDT 111,000 99 85 29,700 111,000 179 92 53,700 

08/09/2005 11:00 CDT 75,600 74 93 15,100 75,600 131 97 26,600 

09/13/2005 11:00 CDT 118,000 95 86 30,200 118,000 151 91 48,300 

10/18/2005 11:00 CDT 76,600 74 94 15,300 76,600 126 97 26,100 

11/15/2005 11:00 CST 57,100 47 99 7,160 57,100 87 99 13,500 

12/06/2005 11:30 CST 69,600 65 89 12,200 69,600 114 95 21,400 

12/20/2005 11:00 CST 86,100 119 93 27,600 86,098 145 95 33,600 

01/10/2006 11:00 CST 92,800 50 81 12,600 92,793 91 90 22,900 

01/24/2006 11:00 CST 116,000 158 93 49,300 115,638 214 95 66,800 

02/07/2006 11:00 CST 218,000 235 87 138,000 218,485 278 89 164,000 

02/22/2006 15:00 CST 127,000 224 83 76,800 127,123 221 83 76,000 

03/07/2006 11:00 CST 89,400 166 81 39,900 89,385 215 85 51,900 

03/21/2006 11:00 CST 148,000 347 96 139,000 147,941 391 96 156,000 

04/04/2006 10:00 CST 123,000 129 89 43,000 123,323 187 93 62,200 

04/18/2006 11:00 CST 148,000 191 63 76,200 147,563 229 78 91,400 

05/02/2006 11:00 CST 161,000 153 89 66,500 160,724 207 92 90,000 

05/16/2006 11:00 CST 165,000 149 93 66,300 164,656 207 95 92,100 

06/06/2006 11:00 CDT 136,000 92 73 33,800 136,000 144 83 53,100 

07/19/2006 11:00 CDT 88,600 70 82 16,700 88,600 120 90 28,600 

08/08/2006 11:00 CDT 72,500 68 96 13,300 72,500 102 98 20,000 

09/12/2006 11:00 CDT 78,100 — — — 78,100 123 93 25,900 

10/11/2006 11:00 CDT 116,000 131 66 41,000 116,000 185 75 57,900 

12/05/2006 11:00 CST 180,000 149 56 72,300 180,000 189 65 91,700 

12/19/2006 11:00 CST 120,000 79 78 25,700 120,000 121 86 39,200 

01/09/2007 11:00 CST 129,000 136 95 47,300 129,000 189 97 65,700 

01/23/2007 11:00 CST 223,000 184 87 111,000 223,000 230 90 138,000 

02/13/2007 11:00 CST 110,000 89 91 26,500 110,000 130 95 38,600 

02/28/2007 11:00 CST 95,000 86 86 22,100 95,000 150 93 38,500 

03/13/2007 11:00 CST 253,000 253 50 173,000 253,000 457 73 313,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 149

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/27/2007 11:00 CST 193,000 330 77 172,000 193,000 246 70 128,000 

04/10/2007 11:00 CST 285,000 187 74 144,000 285,000 238 80 183,000 

04/24/2007 11:00 CST 218,000 155 78 91,000 218,000 210 84 124,000 

05/08/2007 11:00 CDT 184,000 99 92 49,100 184,000 151 95 75,100 

05/22/2007 11:00 CDT 214,000 406 97 234,000 214,000 454 97 262,000 

06/12/2007 11:00 CDT 126,000 269 99 91,500 126,000 344 99 117,000 

07/03/2007 11:00 CDT 85,500 169 100 39,000 85,500 241 100 55,800 

08/07/2007 11:00 CDT 54,700 125 100 18,500 54,700 180 99 26,600 

09/05/2007 11:00 CDT 95,000 123 95 31,600 95,000 188 97 48,300 

10/02/2007 11:00 CDT 58,500 84 99 13,200 58,500 159 100 25,100 

11/06/2007 11:00 CST 128,000 181 80 62,500 128,000 485 44 167,000 

12/04/2007 11:00 CST 82,100 69 92 15,300 82,100 125 96 27,700 

12/18/2007 11:00 CST 134,000 127 69 46,000 134,331 221 66 80,000 

01/02/2008 11:00 CST 233,000 229 70 144,000 233,000 267 74 168,000 

01/15/2008 11:00 CST 157,000 130 71 55,100 157,000 172 78 73,100 

02/05/2008 11:00 CST 121,000 125 94 40,700 121,000 179 95 58,400 

02/26/2008 11:00 CST 276,000 230 81 172,000 276,000 269 84 200,000 

03/11/2008 11:00 CDT 210,000 188 92 106,000 210,000 224 93 127,000 

03/26/2008 11:00 CDT 299,000 201 82 162,000 299,000 227 84 183,000 

04/17/2008 11:00 CDT 477,000 140 48 180,000 477,000 167 57 215,000 

05/06/2008 15:30 CDT 346,000 81 84 75,400 346,000 168 64 156,000 

05/24/2008 11:00 CDT 302,000 100 85 81,500 302,000 146 90 119,000 

06/03/2008 11:00 CDT 309,000 116 67 96,400 309,000 157 80 131,000 

06/17/2008 11:00 CST 302,000 371 90 303,000 302,129 411 91 335,000 

07/01/2008 11:00 CST 338,000 180 82 164,000 337,749 223 84 204,000 

08/05/2008 11:00 CST 159,000 120 82 51,700 158,708 169 87 72,600 

09/16/2008 11:00 CST 36,700 40 98 3,960 36,685 112 100 11,100 

10/07/2008 11:00 CDT 109,000 112 97 32,900 109,000 171 99 50,500 

11/04/2008 11:00 CST 85,800 100 88 23,000 85,800 158 92 36,700 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
150 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/02/2008 11:00 CST 61,100 87 99 14,400 61,100 185 100 30,600 

12/23/2008 11:00 CST 118,000 234 95 74,500 118,000 298 96 94,800 

01/06/2009 11:00 CST 227,000 366 91 224,000 118,000 405 92 129,000 

01/21/2009 11:00 CST 215,000 190 84 110,000 215,000 219 86 127,000 

02/04/2009 11:00 CST 115,000 118 90 36,600 115,000 165 93 51,200 

02/18/2009 11:00 CST 171,000 147 82 68,000 171,000 186 86 85,900 

03/03/2009 11:00 CST 225,000 210 74 128,000 225,000 252 79 153,000 

03/17/2009 11:00 CST 141,000 195 99 74,200 141,000 231 99 87,900 

04/07/2009 11:00 CDT 203,000 205 93 112,000 203,000 254 95 140,000 

04/21/2009 11:00 CDT 254,000 124 89 84,900 254,000 182 93 125,000 

05/05/2009 11:00 CDT 257,000 115 85 80,000 257,000 157 88 109,000 

05/19/2009 11:00 CDT 308,000 91 83 75,700 308,000 143 82 119,000 

06/23/2009 11:00 CDT 160,000 166 99 71,700 160,000 208 100 90,000 

07/21/2009 11:00 CDT 140,000 120 74 45,400 140,000 162 81 61,600 

08/11/2009 11:00 CDT 158,000 109 91 46,300 158,000 145 93 61,600 

09/09/2009 11:00 CDT 112,000 97 88 29,300 112,000 146 93 44,100 

10/06/2009 11:00 CDT 113,000 106 97 32,300 113,000 145 99 44,100 

11/03/2009 11:00 CST 95,300 91 99 23,500 95,000 165 100 43,000 

12/01/2009 11:00 CST 173,000 146 88 68,000 173,000 203 89 95,000 

12/16/2009 11:00 CST 140,000 212 97 80,000 140,000 255 98 96,000 

01/12/2010 11:00 CST 192,000 134 76 69,400 192,000 166 81 86,000 

01/26/2010 11:00 CST 94,700 169 99 43,100 95,000 233 100 60,000 

02/02/2010 12:00 CST 222,000 207 79 124,000 222,000 281 85 169,000 

02/17/2010 11:30 CST 256,000 122 67 84,400 256,000 175 80 121,000 

03/03/2010 11:30 CST 127,000 83 90 28,600 127,000 134 97 46,000 

03/18/2010 11:30 CST 112,000 81 91 24,500 — — — — 

03/30/2010 11:30 CST 267,000 216 82 156,000 267,000 266 85 192,000 

04/13/2010 11:30 CST 331,000 133 64 119,000 331,000 150 74 134,000 

04/28/2010 11:45 CST 168,000 — — — 168,000 119 99 54,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 151

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/11/2010 11:30 CST 311,000 300 69 252,000 311,000 310 72 260,000 

05/26/2010 11:30 CST 357,000 208 62 201,000 357,000 208 62 200,000 

06/09/2010 12:15 CST 295,000 176 56 140,000 295,000 240 73 191,000 

06/23/2010 11:45 CST 236,000 408 79 260,000 236,000 436 87 278,000 

08/03/2010 11:45 CST 204,000 266 87 147,000 204,000 305 92 168,000 

11/01/2010 14:00 CDT 101,000 92 84 25,200 101,000 154 93 42,000 

12/01/2010 14:30 CST 106,000 119 63 34,000 106,000 204 79 58,400 

12/22/2010 13:45 CST 121,000 103 86 33,500 121,000 160 93 52,400 

01/20/2011 12:15 CST 106,000 115 88 32,900 106,000 271 97 77,500 

02/15/2011 14:15 CST 140,000 110 71 41,500 140,000 214 86 80,700 

03/02/2011 11:30 CST 201,000 370 77 201,000 201,000 495 83 269,000 

03/16/2011 12:15 CDT 358,000 286 65 276,000 358,000 341 71 329,000 

03/29/2011 11:10 CDT 411,000 170 44 189,000 411,000 204 56 227,000 

04/12/2011 12:30 CDT 350,000 138 59 131,000 350,000 245 78 232,000 

04/28/2011 11:45 CDT 302,000 105 73 85,800 302,000 174 84 142,000 

05/13/2011 12:45 CDT 641,000 259 35 449,000 641,000 308 45 533,000 

05/18/2011 13:30 CDT 606,000 185 45 303,000 606,000 234 57 382,000 

06/03/2011 12:30 CDT 456,000 53 66 64,700 456,000 109 88 135,000 

06/17/2011 12:30 CDT 324,000 77 83 67,600 324,000 140 92 122,000 

07/18/2011 13:00 CDT 244,000 126 95 82,800 244,000 192 97 126,000 

08/10/2011 13:00 CDT 152,000 111 93 45,600 161,000 228 97 99,200 

08/31/2011 12:00 CDT 124,000 59 96 19,600 124,000 157 99 52,500 

09/27/2011 11:45 CDT 106,000 56 97 16,100 106,000 143 100 41,100 

10/12/2011 12:45 CDT 105,000 50 89 14,200 105,000 138 72 39,000 

11/08/2011 12:30 CST 105,000 50 93 14,300 105,000 159 100 45,000 

12/06/2011 13:10 CST 234,000 301 84 190,000 234,000 547 92 345,000 

12/19/2011 12:45 CST 328,000 187 57 166,000 328,000 278 72 246,000 

02/13/2012 11:45 CST 259,000 111 78 77,400 259,000 188 89 131,000 

03/12/2012 13:15 CST 142,000 126 90 48,100 142,000 266 96 102,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
152 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

04/03/2012 12:45 CST 163,000 120 96 52,600 163,000 250 100 110,000 

04/17/2012 14:15 CST 73,000 — — — 73,000 278 100 55,000 

05/01/2012 13:00 CST 96,000 88 98 22,900 96,000 201 100 52,000 

05/17/2012 12:30 CST 220,000 231 84 137,000 220,000 314 84 186,000 

05/31/2012 13:00 CST 121,000 82 98 26,900 121,000 152 100 50,000 

06/26/2012 13:00 CST 80,000 58 99 12,600 80,000 136 100 29,000 

07/10/2012 12:45 CST 79,000 56 95 11,900 79,000 131 98 28,000 

07/25/2012 12:45 CST 56,000 60 99 9,030 57,000 134 100 21,000 

08/08/2012 13:30 CST 79,000 69 97 14,600 78,000 140 100 29,000 

08/27/2012 12:00 CST 50,000 43 95 5,740 50,000 111 100 15,000 

09/11/2012 11:45 CST 58,000 41 100 6,440 58,000 101 100 16,000 

09/25/2012 12:00 CST 45,000 48 100 5,850 45,000 128 100 15,000 

10/25/2012 11:56 CDT 59,000 78 96 12,400 59,000 158 100 25,000 

12/05/2012 12:00 CST 61,000 30 98 4,900 61,000 126 100 21,000 

12/18/2012 12:15 CST 68,400 108 95 19,800 68,400 151 98 28,000 

01/23/2013 12:15 CST 172,000 347 93 161,000 17,200 389 94 18,000 

02/06/2013 13:45 CST 209,000 188 77 106,000 209,000 228 81 129,000 

02/28/2013 13:30 CST 144,000 146 87 56,900 144,000 210 92 82,000 

03/04/2013 12:30 CST 134,000 137 90 49,700 134,000 197 94 71,000 

03/19/2013 13:15 CDT 176,000 158 77 75,100 137,000 222 84 82,000 

04/08/2013 13:45 CDT 205,000 127 77 70,200 205,000 181 85 100,000 

05/01/2013 12:15 CDT 281,000 272 90 206,000 — — — — 

05/15/2013 12:45 CDT 368,000 139 48 138,000 — — — — 

05/30/2013 12:15 CDT 335,000 80 82 72,100 335,000 130 90 117,000 

06/13/2013 12:20 CDT 265,000 215 97 154,000 265,000 286 99 205,000 

06/26/2013 13:15 CDT 276,000 91 92 67,600 276,000 184 97 137,000 

07/10/2013 12:45 CDT 287,000 264 77 204,000 287,000 349 83 271,000 

07/24/2013 12:00 CDT 274,000 106 84 78,200 274,000 176 90 130,000 

08/07/2013 12:45 CDT 137,000 64 92 23,800 137,000 130 97 48,000 

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 153

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

09/25/2013 13:15 CDT 57,800 49 98 7,600 57,800 123 100 19,000 

11/21/2013 13:00 CST 81,500 65 97 14,200 81,500 139 100 31,000 

12/11/2013 13:15 CST 78,000 145 78 30,600 — — — — 

01/22/2014 13:13 CST 194,000 153 66 79,900 — — — — 

02/05/2014 12:45 CST 105,000 96 94 27,100 — — — — 

02/27/2014 12:45 CST 137,000 98 83 36,100 — — — — 

03/19/2014 12:30 CDT 156,000 120 85 50,600 — — — — 

04/02/2014 12:00 CDT 107,000 166 99 47,800 — — — — 

04/17/2014 12:00 CDT 237,000 276 93 177,000 — — — — 

05/01/2014 12:15 CDT 166,000 120 96 53,600 — — — — 

05/29/2014 12:15 CDT 221,000 206 89 123,000 — — — — 

06/12/2014 12:30 CDT 155,000 89 95 37,200 — — — — 

06/24/2014 12:00 CDT 217,000 343 98 201,000 — — — — 

07/10/2014 12:15 CDT 217,000 256 91 150,000 — — — — 

07/24/2014 13:00 CDT 178,000 184 97 88,200 — — — — 

08/06/2014 12:00 CDT 105,000 73 94 20,700 — — — — 

08/19/2014 13:15 CDT 87,600 50 98 11,800 — — — — 

09/04/2014 12:40 CDT 107,000 129 98 37,200 — — — — 

09/19/2014 11:00 CDT 121,000 200 96 65,300 — — — — 

11/20/2014 12:00 CST 108,000 71 90 20,800 — — — — 

12/09/2014 11:00 CST 126,000 58 92 19,900 — — — — 

01/08/2015 10:45 CST 107,000 140 95 40,500 — — — — 

01/20/2015 11:00 CST 119,000 99 89 31,800 — — — — 

02/03/2015 14:00 CST 89,300 48 95 11,600 — — — — 

1

Original result for discharge on 03/30/1999 was misrecorded and should have been 284,000 cubic feet per second, and the resulting sediment discharge for 

that day should have been 139,000 short tons per day.

Table 4–1. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Old River Outflow 

Channel below hydropower channel (U.S. Geological Survey station 07381482).—Continued

[Sites U.S. Geological Survey (USGS) 07381482 and USGS 310355091411500 (Old River Outflow Channel near Knox Landing) are considered equivalent 

with respect to measurements of discharge and water-quality parameters. The location of the suspended-sediment sampling site was changed on October 1, 2009, 

when the USGS assumed responsibility for maintaining the streamgage at the new location. Discharge data were supplied by the U.S. Army Corps of Engineers 

and the USGS. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water Information System (NWIS) 

at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. 

Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, 

eastern standard time; CDT, central daylight time; CST, central standard time]
154 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/03/1989 12:45 CDT 25,900 359 98 25,100 25,900 95 98 6,640 

10/20/1989 12:00 CDT 18,600 — — — 18,600 80 100 4,040 

11/17/1989 12:30 CST 26,200 — — — 26,200 73 100 5,180 

12/13/1989 13:00 CST 26,200 — — — 26,200 97 99 6,830 

01/31/1990 14:00 CST 239,000 945 44 610,000 — — — — 

02/08/1990 14:30 CST 231,000 1,160 43 721,000 — — — — 

03/15/1990 11:30 CST 219,000 848 67 501,000 219,000 969 64 573,000 

04/06/1990 11:30 CDT 247,000 701 58 468,000 247,000 803 50 535,000 

05/16/1990 11:30 CDT 270,000 1,190 77 871,000 270,000 1,490 66 1,090,000 

05/25/1990 14:30 CDT 303,000 828 57 677,000 303,000 909 53 744,000 

06/12/1990 14:30 CDT 259,000 415 65 290,000 259,000 522 62 365,000 

06/22/1990 14:30 CDT 245,000 527 61 349,000 245,000 668 51 442,000 

07/12/1990 14:30 CDT 105,000 182 89 51,600 105,000 206 91 58,400 

07/25/1990 15:00 CDT 38,300 114 72 11,800 38,300 161 91 16,500 

08/13/1990 10:55 CDT 43,500 226 91 26,500 43,500 373 91 43,900 

08/29/1990 10:15 CDT 28,900 44 97 3,450 28,900 52 100 4,020 

09/18/1990 12:30 CDT 29,100 — — — 29,100 37 97 2,890 

10/11/1990 09:30 CDT 29,000 84 90 6,540 29,000 85 100 6,670 

10/25/1990 11:00 CDT 59,000 133 94 21,200 59,000 154 97 24,500 

11/21/1990 10:45 CST 31,000 95 98 7,950 31,000 80 97 6,700 

12/05/1990 12:45 CST 47,000 105 90 13,300 47,000 128 95 16,200 

12/27/1990 08:30 CST 124,000 — — — 124,000 605 61 203,000 

01/18/1991 11:15 CST 193,000 318 77 166,000 193,000 422 83 220,000 

01/30/1991 13:40 CST 203,000 283 86 155,000 203,000 348 89 191,000 

02/07/1991 13:40 CST 212,000 248 52 142,000 212,000 263 68 151,000 

02/26/1991 12:10 CST 198,000 552 47 295,000 198,000 564 54 302,000 

03/12/1991 10:50 CST 189,000 168 57 85,900 189,000 186 56 95,000 

04/24/1991 11:30 CDT 250,000 655 53 442,000 250,000 697 58 471,000 

05/21/1991 12:30 CDT 302,000 — — — 302,000 701 48 572,000 

06/04/1991 11:15 CDT 235,000 — — — 235,000 318 57 202,000 

06/19/1991 12:30 CDT 181,000 454 57 222,000 181,000 398 71 195,000 
Appendix 4 155

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/08/1991 11:30 CDT 96,700 287 65 74,900 97,000 287 77 75,100 

07/25/1991 11:55 CDT 17,000 — — — 17,000 72 92 3,300 

08/22/1991 12:33 CDT 19,800 66 87 3,530 20,000 127 94 6,900 

09/13/1991 12:30 CDT 24,000 — — — 24,000 75 91 4,900 

10/11/1991 12:15 CDT 21,100 — — — 21,000 42 98 2,400 

11/08/1991 12:30 CST 134,000 807 57 292,000 134,000 754 70 273,000 

12/05/1991 13:00 CST 157,000 617 48 262,000 157,000 590 62 250,000 

01/10/1992 11:45 CST 151,000 764 51 312,000 151,000 577 60 235,000 

02/06/1992 11:15 CST 134,000 568 39 206,000 134,000 489 54 177,000 

02/20/1992 11:55 CST 181,000 — — — 181,000 639 48 312,000 

03/06/1992 12:35 CST 167,000 — — — 167,000 518 54 234,000 

03/20/1992 11:20 CST 167,000 353 62 159,000 167,000 394 56 178,000 

04/03/1992 11:55 CST 117,000 185 68 58,600 117,000 169 64 53,300 

04/23/1992 12:25 CDT 76,000 183 67 37,600 76,000 163 76 33,400 

05/06/1992 11:50 CDT 65,000 131 94 23,000 65,000 148 97 26,000 

05/21/1992 12:10 CDT 23,000 82 99 5,090 23,000 105 99 6,500 

06/04/1992 12:10 CDT 64,000 346 83 59,700 64,000 358 90 61,900 

06/17/1992 12:00 CDT 118,000 368 63 117,000 118,000 433 78 138,000 

07/10/1992 12:00 CDT 85,000 289 75 66,300 85,000 306 84 70,100 

07/23/1992 11:25 CDT 66,000 177 91 31,600 66,000 196 97 35,000 

08/21/1992 12:20 CDT 35,000 61 100 5,720 35,000 82 100 7,750 

11/05/1992 15:00 CST 29,000 89 98 6,990 29,000 109 100 8,510 

12/08/1992 09:30 CST 51,700 140 91 19,500 — — — — 

01/12/1993 12:00 CST 132,000 610 48 218,000 132,000 551 59 196,000 

02/25/1993 10:30 CST 122,000 622 52 205,000 122,000 670 56 221,000 

03/23/1993 11:00 CST — 451 68 — — — — — 

04/20/1993 08:30 CDT — 151 63 — — — — — 

06/22/1993 10:00 CDT 76,400 352 97 72,500 76,400 406 97 84,000 

07/14/1993 12:00 CDT 32,700 75 40 6,640 32,700 92 66 8,130 

07/27/1993 12:20 CDT 19,400 55 95 2,850 19,400 74 100 3,900 

08/17/1993 11:00 CDT 18,000 19 93 927 18,000 53 100 2,600 

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]
156 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

09/21/1993 10:00 CDT 17,000 23 95 1,050 17,000 35 97 1,600 

10/05/1993 09:30 CDT 16,000 36 95 1,540 16,000 47 99 2,000 

10/21/1993 11:00 CDT 29,000 67 61 5,270 29,000 120 73 1 94,000 

11/16/1993 14:30 CST 57,000 265 90 40,800 57,000 262 92 40,300 

11/30/1993 10:00 CST 47,000 67 90 8,460 47,000 77 95 9,800 

12/06/1993 10:30 CST 69,000 87 62 16,200 69,000 87 71 16,300 

12/20/1993 10:30 CST 124,000 271 81 90,700 124,000 296 83 99,000 

01/31/1994 10:00 CST 174,000 1,000 50 471,000 174,000 981 50 461,000 

02/14/1994 14:00 CST 142,000 — — — 142,000 357 55 137,000 

03/14/1994 13:00 CST 191,000 490 61 253,000 191,000 463 62 239,000 

03/28/1994 10:30 CST 128,000 194 42 67,000 128,000 216 35 75,000 

04/11/1994 11:30 CDT 112,000 148 50 44,700 112,000 164 38 50,000 

04/25/1994 10:30 CDT 56,000 81 57 12,300 56,000 79 35 12,000 

05/03/1994 10:30 CDT 42,000 — — — 42,000 51 68 5,800 

05/17/1994 10:00 CDT 111,000 187 97 56,000 111,000 193 96 58,000 

06/01/1994 10:30 CDT 77,000 235 94 48,900 77,000 239 94 50,000 

06/14/1994 10:30 CDT 48,000 167 96 21,700 48,000 172 95 22,300 

06/28/1994 09:30 CDT 27,000 — — — 27,000 121 97 8,900 

07/12/1994 10:00 CDT 19,000 85 91 4,380 19,000 99 91 5,100 

07/26/1994 09:15 CDT 50,000 189 75 25,500 50,000 289 82 39,000 

08/09/1994 14:30 CDT 31,000 59 81 4,960 31,000 129 91 10,800 

08/23/1994 14:30 CDT — 71 76 — — — — — 

09/07/1994 10:30 CDT 11,000 31 91 908 — — — — 

10/04/1994 10:30 CDT — 40 98 — — — — — 

10/18/1994 10:15 CDT 69,000 — — — — — — — 

11/01/1994 10:00 CST — 104 73 — — — — — 

11/16/1994 10:30 CST 79,000 407 60 86,700 — — — — 

11/29/1994 12:00 CST — 481 50 — — — — — 

12/13/1994 10:30 CST 72,000 78 86 15,100 — — — — 

01/31/1995 10:00 CST 147,000 — — — — — — — 

02/14/1995 10:00 CST 100,000 — — — 100,000 90 96 24,200 

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 157

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/28/1995 10:30 CST 54,000 57 73 8,370 — — — — 

03/14/1995 10:15 CST 162,000 — — — 162,000 485 51 212,000 

04/04/1995 10:00 CDT 120,000 — — — — — — — 

04/18/1995 09:30 CDT 114,000 — — — 114,000 374 61 115,000 

05/02/1995 09:30 CDT 139,000 602 40 226,000 — — — — 

05/23/1995 11:00 CDT 155,000 398 66 167,000 155,000 462 68 193,000 

06/13/1995 10:00 CDT 59,000 176 85 28,100 — — — — 

06/27/1995 10:00 CDT — 219 75 — — — — — 

07/25/1995 10:00 CDT — 85 88 — — — — — 

08/08/1995 11:00 CDT 19,000 65 91 3,340 19,000 61 94 3,140 

08/29/1995 10:00 CDT — 21 75 — — — — — 

09/27/1995 10:30 CDT 24,000 41 91 2,630 24,000 126 99 8,180 

10/24/1995 11:00 CDT — 39 96 — — — — — 

11/07/1995 10:00 CST — 44 99 — — — — — 

12/12/1995 10:30 CST — 48 84 — — — — — 

01/09/1996 13:00 CST — 104 93 — — — — — 

02/13/1996 14:00 CST 22,000 153 98 9,070 — — — — 

03/06/1996 13:00 CST 8,000 65 97 1,400 — — — — 

03/27/1996 10:00 CST 24,000 39 100 2,500 — — — — 

04/09/1996 13:00 CDT 31,200 132 100 11,200 — — — — 

04/12/1996 11:30 CDT 34,000 66 97 6,050 — — — — 

04/19/1996 12:15 CDT 74,100 218 98 43,600 — — — — 

05/14/1996 12:00 CDT 35,900 60 100 5,810 — — — — 

06/05/1996 11:00 CDT 32,900 121 98 10,700 — — — — 

07/16/1996 11:00 CDT 26,800 175 93 12,700 — — — — 

07/30/1996 09:30 CDT 19,900 39 97 2,070 — — — — 

08/13/1996 09:00 CDT 38,500 60 91 6,180 — — — — 

09/10/1996 09:30 CDT 28,200 54 94 4,100 — — — — 

10/01/1996 09:00 CDT 74,500 338 65 68,000 — — — — 

10/24/1996 11:00 CDT 23,400 24 100 1,500 — — — — 

11/19/1996 12:00 CST — 251 86 — — — — — 

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]
158 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/10/1996 12:00 CST — 518 65 — — — — — 

01/21/1997 11:00 CST 80,000 207 65 44,700 — — — — 

02/04/1997 10:00 CST 112,000 272 59 82,300 — — — — 

02/25/1997 11:00 CST 230,000 622 41 386,000 230,000 733 51 455,000 

04/01/1997 12:00 CST 163,000 87 58 38,400 163,000 149 80 65,000 

04/22/1997 13:30 CDT 192,000 464 50 240,000 192,000 512 60 265,000 

05/06/1997 11:15 CDT 246,000 445 54 296,000 246,000 405 55 269,000 

05/20/1997 10:00 CDT 165,000 421 35 188,000 — — — — 

06/10/1997 10:00 CDT 101,000 249 75 67,900 — — — — 

07/01/1997 12:00 CDT 58,000 46 84 7,230 — — — — 

07/15/1997 12:00 CDT 27,500 72 70 5,360 — — — — 

08/12/1997 10:00 CDT 19,900 49 100 2,640 — — — — 

08/25/1997 12:00 CDT 15,400 17 87 702 — — — — 

09/23/1997 12:00 CDT 3,280 30 100 262 — — — — 

10/16/1997 10:15 CDT 5,850 26 100 411 6,000 210 100 3,400 

11/04/1997 09:00 CST 14,400 26 98 1,020 14,000 101 100 3,810 

12/09/1997 09:00 CST 45,500 129 86 15,800 46,000 137 88 17,000 

01/13/1998 12:30 CST 260,000 1,200 46 846,000 260,000 1,200 49 838,000 

02/05/1998 12:00 CST 238,000 661 44 425,000 240,000 612 48 394,000 

02/24/1998 11:30 CST 172,000 300 53 139,000 171,000 294 54 136,000 

03/17/1998 09:30 CST 166,000 444 35 199,000 166,000 554 48 248,000 

04/07/1998 11:00 CDT 145,000 233 73 91,100 145,000 312 81 122,000 

05/07/1998 09:00 CDT 26,300 89 54 6,300 — — — — 

05/19/1998 09:00 CDT 24,500 72 48 4,760 25,000 267 87 18,000 

06/24/1998 09:30 CDT 10,600 21 69 608 11,000 87 93 2,580 

07/13/1998 09:30 CDT 11,200 32 92 957 11,000 76 99 2,250 

08/18/1998 09:30 CDT 14,200 57 77 2,170 140,000 174 93 65,800 

11/17/1998 10:00 CST 68,800 135 80 25,100 69,000 179 86 33,300 

12/08/1998 11:00 CST 26,100 46 85 3,270 26,000 85 93 5,980 

01/13/1999 10:00 CST 134,000 — — — 134,000 440 59 159,000 

02/09/1999 09:00 CST 204,000 247 29 136,000 204,000 313 44 172,000 

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 159

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/09/1999 09:00 CST 102,000 198 63 54,600 102,000 215 68 59,100 

04/14/1999 10:00 CDT 170,000 240 57 110,000 170,000 258 60 118,000 

05/25/1999 09:45 CDT 52,800 91 70 13,000 52,800 158 83 22,600 

07/07/1999 10:00 CDT 55,500 47 94 7,030 55,000 137 99 20,400 

12/07/1999 09:30 CST 49,400 21 100 2,750 — — — — 

01/11/2000 13:00 CST 7,830 38 97 803 7,830 80 100 1,690 

02/08/2000 10:00 CST 16,300 — — — 16,300 327 100 14,400 

03/14/2000 10:00 CST 25,900 41 91 2,880 25,900 87 99 6,100 

04/11/2000 10:30 CDT 143,000 344 52 133,000 143,000 356 55 138,000 

05/09/2000 10:00 CDT 89,100 148 79 35,700 89,100 170 83 40,800 

06/13/2000 10:00 CDT 42,200 58 100 6,560 42,200 63 100 7,230 

07/18/2000 09:30 CDT 28,200 — — — 28,200 46 95 3,480 

08/01/2000 10:30 CDT 13,900 50 100 1,860 13,900 39 99 1,470 

12/05/2000 10:00 CST 105,000 288 64 81,600 105,000 312 67 88,100 

01/04/2001 10:00 CST 190,000 883 56 453,000 190,000 932 59 477,000 

02/06/2001 09:30 CST 153,000 343 40 142,000 153,000 347 41 144,000 

03/16/2001 11:00 CST 299,000 309 45 249,000 299,000 328 49 265,000 

04/10/2001 09:30 CDT 186,000 683 44 343,000 186,000 573 55 288,000 

05/08/2001 09:30 CDT 62,000 70 97 11,600 62,000 88 99 14,700 

06/12/2001 09:30 CDT 88,900 108 90 25,900 88,900 145 94 34,900 

01/29/2002 13:30 CST 146,000 227 54 89,300 146,000 251 59 99,000 

02/12/2002 10:00 CST 144,000 142 71 55,200 144,000 169 75 65,600 

03/12/2002 10:00 CST 59,200 50 89 7,990 59,200 66 92 10,600 

04/12/2002 09:30 CDT 204,000 209 69 115,000 204,000 221 71 122,000 

05/14/2002 09:15 CDT 92,400 98 75 24,400 92,400 118 80 29,400 

06/11/2002 09:30 CDT 66,300 30 82 5,430 66,300 52 91 9,390 

01/14/2003 10:00 CST 99,400 96 78 25,800 99,400 122 83 32,800 

02/11/2003 10:30 CST 45,900 92 90 11,300 45,900 227 96 28,100 

03/10/2003 11:00 CST 150,000 93 74 37,700 150,000 121 80 48,900 

04/08/2003 09:30 CST 69,700 78 75 14,700 69,700 108 83 20,300 

05/16/2003 13:00 CST 40,400 48 94 5,280 40,400 79 97 8,630 

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]
160 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 4–2. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Red River above Old 

River Outflow Channel above Simmesport, Louisiana (U.S. Geological Survey station 310408091424500).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers. The five-digit “pcode” below each constituent name uniquely identifies that constituent in 

the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter 

(p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be 

corrected because of a lack of metadata. CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

06/11/2003 11:30 CST 22,500 78 92 4,760 22,500 112 99 6,760 

01/24/2004 11:00 CST 37,400 53 99 5,310 — — — — 

02/20/2004 11:30 CST 133,000 108 88 38,800 133,000 143 91 51,300 

03/09/2004 11:30 CST 135,000 178 54 64,800 135,000 224 64 81,900 

04/27/2004 11:30 CDT 29,700 103 99 8,260 29,700 88 100 7,020 

05/18/2004 12:00 CST 110,000 153 95 45,400 110,000 178 96 53,100 

06/29/2004 11:30 CDT 147,000 143 83 56,900 147,000 193 88 76,500 

12/07/2004 13:00 CST 163,000 265 66 117,000 — — — — 

01/04/2005 11:45 CST 110,000 65 86 19,400 — — — — 

1

Original result for suspended-sediment discharge on 10/21/1993 was miscalculated as 94,000 short tons per day and should have been reported as 9,400 short 

tons per day.
Appendix 4 161

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/04/1989 11:15 EDT 135,000 — — — — — — — 

10/17/1989 11:15 EDT 132,000 81 90 28,800 132,000 87 97 31,200 

10/31/1989 11:15 EST 136,000 90 86 33,100 136,000 123 99 45,300 

11/14/1989 11:15 EST 99,000 87 95 23,200 99,000 110 97 29,400 

11/28/1989 11:15 EST 140,000 96 94 36,200 140,000 129 98 48,900 

12/12/1989 11:15 EST 108,000 59 96 17,300 108,000 81 100 23,600 

12/27/1989 11:15 EST 76,000 59 82 12,100 76,000 108 91 22,100 

01/10/1990 11:15 EST 128,000 202 91 69,700 128,000 242 94 83,500 

01/23/1990 11:15 EST 217,000 637 79 373,000 217,000 641 79 176,000 

02/09/1990 11:15 EST 304,000 581 83 477,000 304,000 630 73 130,000 

02/23/1990 11:15 EST 423,000 227 66 259,000 — — — — 

03/06/1990 11:15 EST 459,000 102 76 127,000 459,000 132 84 164,000 

03/20/1990 11:15 EST 364,000 487 81 478,000 364,000 494 84 186,000 

04/03/1990 11:15 EDT 416,000 445 72 500,000 416,000 469 81 126,000 

04/17/1990 11:15 EDT 339,000 517 74 474,000 339,000 537 79 192,000 

05/01/1990 11:15 EDT 322,000 477 69 414,000 322,000 435 74 178,000 

05/15/1990 13:15 EDT 402,000 750 73 814,000 402,000 860 78 133,000 

05/18/1990 11:15 EDT 407,000 682 76 750,000 407,000 657 84 122,000 

05/22/1990 11:15 EDT 401,000 589 72 638,000 401,000 586 79 134,000 

05/25/1990 11:15 EDT 412,000 373 83 414,000 412,000 493 90 149,000 

06/01/1990 11:15 EDT 476,000 413 60 531,000 476,000 425 67 146,000 

06/05/1990 11:15 EDT 515,000 348 63 483,000 515,000 370 70 114,000 

06/12/1990 11:15 EDT 521,000 281 70 395,000 521,000 292 76 110,000 

06/26/1990 11:15 EDT 398,000 385 69 413,000 398,000 448 75 181,000 

07/10/1990 11:15 EDT 271,000 382 74 280,000 271,000 429 81 114,000 

07/24/1990 11:15 EDT 203,000 202 72 111,000 203,000 244 80 134,000 

08/07/1990 11:15 EDT 163,000 196 89 86,100 163,000 203 91 89,500 

08/21/1990 11:00 EDT 152,000 158 78 64,700 152,000 175 84 71,900 

09/05/1990 11:00 EDT 153,000 101 83 41,600 153,000 123 89 50,700 

09/18/1990 12:00 EDT 137,000 142 56 52,500 137,000 195 50 72,100 

10/02/1990 10:30 EDT 114,000 304 30 93,400 114,000 190 60 58,500 

10/18/1990 10:30 EDT 143,000 374 54 144,000 143,000 322 68 124,000 
162 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/30/1990 11:00 EST 140,000 136 58 51,300 140,000 138 72 52,300 

11/20/1990 12:00 EST 121,000 86 65 28,200 121,000 93 77 30,400 

11/27/1990 12:00 EST 118,000 72 68 22,900 118,000 80 78 25,400 

12/11/1990 08:00 EST 159,000 352 33 151,000 159,000 306 46 131,000 

01/02/1991 12:00 EST 367,000 484 48 479,000 367,000 505 55 501,000 

01/15/1991 12:30 EST 575,000 223 91 346,000 — — — — 

01/29/1991 12:30 EST 543,000 339 35 497,000 543,000 324 45 476,000 

02/12/1991 13:00 EST 287,000 281 50 217,000 287,000 296 58 229,000 

02/26/1991 13:00 EST 387,000 343 59 359,000 387,000 354 65 370,000 

03/12/1991 12:30 EST 431,000 226 26 263,000 431,000 234 41 272,000 

03/26/1991 12:30 EST 309,000 241 48 201,000 309,000 240 54 200,000 

04/09/1991 12:30 EDT 361,000 231 50 225,000 361,000 230 61 224,000 

04/23/1991 12:30 EDT 435,000 723 50 849,000 435,000 688 59 808,000 

05/07/1991 12:30 EDT 488,000 664 41 874,000 488,000 636 49 838,000 

05/21/1991 12:30 EDT 432,000 643 44 750,000 432,000 490 60 572,000 

06/04/1991 12:30 EDT 388,000 381 52 399,000 388,000 377 60 395,000 

06/18/1991 12:30 EDT 299,000 550 53 444,000 — — — — 

07/02/1991 12:30 EDT 232,000 — — — 232,000 322 77 202,000 

07/16/1991 12:30 EDT 141,000 135 83 51,300 141,000 156 86 59,000 

07/30/1991 12:30 EDT 110,000 — — — 110,000 157 95 47,000 

08/13/1991 12:30 EDT 99,000 70 55 18,800 99,000 216 31 58,000 

08/27/1991 12:30 EDT 88,000 44 96 10,300 88,000 53 98 12,000 

09/10/1991 12:30 EDT 84,000 — — — 84,000 70 92 16,000 

09/23/1991 12:30 EDT 71,000 33 100 6,240 71,000 53 100 10,000 

10/08/1991 12:30 EDT 72,000 70 70 13,600 72,000 119 56 23,100 

10/22/1991 12:30 EDT 68,000 — — — 68,000 76 82 14,000 

11/05/1991 12:30 EST 173,000 — — — 173,000 1,030 91 482,000 

11/19/1991 12:30 EST 144,000 — — — 144,000 209 79 81,000 

12/03/1991 12:30 EST 236,000 441 54 281,000 236,000 438 59 279,000 

12/17/1991 12:30 EST 378,000 575 54 587,000 378,000 507 57 517,000 

12/31/1991 12:30 EST 324,000 623 53 545,000 324,000 655 53 573,000 

01/14/1992 12:30 EST 278,000 — — — 278,000 527 61 395,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 163

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/30/1992 12:30 EST 206,000 — — — 206,000 523 63 291,000 

02/11/1992 12:30 EST 166,000 — — — 166,000 274 62 123,000 

02/19/1992 12:30 EST 196,000 556 68 294,000 196,000 563 70 298,000 

03/10/1992 12:30 EST 270,000 — — — 270,000 411 62 299,000 

03/24/1992 12:30 EST 315,000 — — — 315,000 401 62 341,000 

04/07/1992 12:30 EDT 286,000 274 57 212,000 286,000 286 68 221,000 

04/22/1992 12:30 EDT 183,000 151 70 74,700 183,000 167 77 82,300 

05/05/1992 12:30 EDT 263,000 419 77 298,000 263,000 432 83 307,000 

05/18/1992 12:30 EDT 179,000 158 67 76,200 179,000 171 79 82,500 

06/02/1992 12:00 EDT 131,000 158 80 55,800 131,000 165 89 58,500 

06/16/1992 12:30 EDT 205,000 574 87 318,000 205,000 549 92 304,000 

06/30/1992 12:30 EDT 169,000 — — — 169,000 193 92 88,000 

07/14/1992 12:30 EDT 151,000 167 90 68,300 151,000 168 95 68,500 

07/28/1992 12:30 EDT 214,000 — — — 214,000 309 82 179,000 

08/18/1992 12:30 EDT 230,000 325 85 202,000 230,000 288 88 179,000 

08/25/1992 11:30 EDT 170,000 171 81 78,300 700,000 155 89 293,000 

09/09/1992 12:30 EDT 117,000 279 65 88,100 117,000 266 65 84,000 

09/24/1992 12:30 EDT 123,000 154 87 51,100 123,000 192 86 63,900 

10/08/1992 12:30 EDT 158,000 177 77 75,500 158,000 242 88 103,000 

10/20/1992 12:30 EDT 83,700 146 93 32,900 83,700 157 94 35,500 

11/03/1992 12:30 EST 96,200 80 95 20,700 96,200 92 96 23,800 

11/17/1992 12:30 EST 146,000 141 70 55,400 146,000 167 81 65,900 

12/01/1992 12:30 EST 271,000 439 42 321,000 271,000 495 56 362,000 

12/15/1992 11:00 EST 229,000 281 63 174,000 229,000 231 65 143,000 

12/31/1992 12:30 EST 348,000 711 55 668,000 348,000 613 56 576,000 

01/14/1993 10:00 EST 363,000 577 37 565,000 363,000 545 45 535,000 

01/28/1993 12:30 EST 364,000 352 37 346,000 364,000 355 46 349,000 

02/11/1993 11:30 EST 297,000 — — — 297,000 247 53 198,000 

02/25/1993 14:00 EST 260,000 364 58 255,000 260,000 379 65 266,000 

03/09/1993 10:00 EST 343,000 516 64 477,000 356,000 508 70 488,000 

03/25/1993 12:30 EST 435,000 420 54 493,000 435,000 425 61 499,000 

04/08/1993 11:30 EDT 411,000 274 48 303,000 411,000 345 60 383,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
164 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/04/1993 15:00 EDT 465,000 — — — 465,000 220 48 276,000 

05/20/1993 10:30 EDT 492,000 221 59 294,000 492,000 237 66 315,000 

06/03/1993 13:30 EDT 421,000 259 65 295,000 421,000 283 73 321,000 

06/14/1993 10:30 EDT 260,000 300 80 210,000 260,000 292 79 205,000 

07/15/1993 12:00 EDT 279,000 376 88 283,000 279,000 409 88 308,000 

07/29/1993 12:45 EDT 330,000 272 77 242,000 330,000 302 81 267,000 

08/10/1993 14:00 EDT 342,000 291 60 269,000 342,000 323 64 298,000 

08/26/1993 12:30 EDT 336,000 165 66 149,000 336,000 205 75 186,000 

09/08/1993 15:00 EDT 233,000 195 88 122,000 233,000 226 91 142,000 

09/23/1993 11:30 EDT 212,000 174 83 99,400 212,000 204 78 117,000 

10/07/1993 11:00 EDT 286,000 259 73 200,000 286,000 270 75 209,000 

10/21/1993 15:00 EDT 217,000 173 80 101,000 217,000 208 87 122,000 

11/04/1993 11:30 EST 183,000 118 84 58,500 183,000 134 88 66,100 

11/18/1993 11:00 EST 177,000 422 93 202,000 177,000 420 93 201,000 

12/02/1993 11:30 EST 329,000 297 54 264,000 329,000 298 57 265,000 

12/08/1993 10:00 EST 316,000 269 60 230,000 316,000 267 66 228,000 

12/22/1993 12:00 EST 377,000 248 52 252,000 377,000 336 46 342,000 

01/05/1994 11:00 EST 210,000 137 78 77,400 210,000 150 83 2848,000 

01/19/1994 15:00 EST 252,000 285 80 194,000 252,000 295 81 201,000 

02/02/1994 11:00 EST 290,000 557 57 436,000 290,000 566 62 443,000 

02/16/1994 11:30 EST 387,000 352 37 367,000 387,000 339 42 354,000 

03/02/1994 13:30 EST 415,000 339 53 380,000 415,000 289 61 324,000 

03/16/1994 12:00 EST 478,000 398 43 514,000 478,000 360 49 464,000 

03/30/1994 10:30 EST 462,000 — — — 462,000 161 47 201,000 

04/13/1994 11:30 EDT 396,000 120 49 128,000 396,000 589 13 629,000 

05/02/1994 07:00 EDT 467,000 215 31 271,000 467,000 201 40 253,000 

05/18/1994 10:30 EDT 451,000 164 50 199,000 451,000 205 64 250,000 

05/31/1994 12:30 EDT 333,000 131 74 117,000 333,000 148 79 133,000 

06/15/1994 10:30 EDT 169,000 — — — 169,000 152 96 69,000 

06/27/1994 15:00 EDT 157,000 133 95 56,200 157,000 162 95 69,000 

07/13/1994 12:30 EDT 149,000 — — — 149,000 221 98 89,000 

07/28/1994 12:00 EDT 159,000 — — — 159,000 343 93 147,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 165

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/17/1994 12:00 EDT 126,000 55 92 18,700 126,000 78 95 26,000 

08/24/1994 10:00 EDT 83,000 52 92 11,600 — — — — 

09/06/1994 14:00 EDT 117,000 39 73 12,300 — — — — 

10/05/1994 12:00 EDT 88,000 39 94 9,340 88,000 55 96 13,000 

10/19/1994 10:30 EDT 108,000 — — — — — — — 

11/09/1994 12:00 EST 102,000 89 86 24,400 102,000 103 89 28,000 

11/15/1994 12:00 EST 153,000 295 86 122,000 — — — — 

11/30/1994 10:00 EST 153,000 202 87 83,400 — — — — 

12/21/1994 12:00 EST 262,000 508 75 359,000 — — — — 

12/28/1994 12:00 EST 224,000 255 65 154,000 224,000 272 62 165,000 

01/04/1995 08:00 EST 163,000 182 65 80,200 163,000 187 64 82,500 

01/25/1995 11:30 EST 300,000 543 63 440,000 300,000 555 66 449,000 

02/08/1995 12:00 EST 280,000 275 51 208,000 280,000 334 58 253,000 

02/22/1995 12:30 EST 181,000 153 79 74,700 181,000 188 84 92,000 

03/08/1995 12:30 EST 258,000 468 67 326,000 258,000 516 71 360,000 

03/21/1995 14:00 EST 340,000 319 56 293,000 340,000 374 60 343,000 

04/05/1995 11:00 EDT 189,000 155 78 79,200 189,000 188 82 95,800 

04/19/1995 12:00 EDT 179,000 195 75 94,200 179,000 251 80 121,000 

05/03/1995 11:30 EDT 335,000 321 67 290,000 335,000 358 72 323,000 

05/16/1995 12:00 EDT 335,000 443 76 401,000 335,000 505 77 457,000 

05/31/1995 12:30 EDT 448,000 349 56 422,000 448,000 374 62 452,000 

06/14/1995 12:00 EDT 555,000 250 34 374,000 555,000 277 44 415,000 

06/28/1995 09:00 EDT 487,000 173 57 228,000 487,000 175 62 230,000 

07/11/1995 12:00 EDT 292,000 222 94 175,000 292,000 230 93 181,000 

08/02/1995 12:00 EDT 153,000 106 95 43,700 153,000 119 96 49,200 

08/16/1995 12:00 EDT 191,000 150 90 77,400 191,000 178 93 91,500 

08/30/1995 12:00 EDT 140,000 110 87 41,500 140,000 134 92 50,700 

09/13/1995 12:00 EDT 91,000 65 96 16,000 91,000 95 99 23,200 

09/28/1995 12:00 EDT 88,000 41 94 9,800 88,000 90 99 21,500 

10/11/1995 12:00 EDT 85,000 — — — 85,000 121 99 27,800 

10/25/1995 12:00 EDT 109,000 65 90 19,000 109,000 126 97 37,200 

11/08/1995 12:00 EST 104,000 — — — 104,000 118 98 33,100 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
166 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/21/1995 13:00 EST 169,000 142 81 65,000 169,000 175 85 79,900 

12/06/1995 14:00 EST 120,000 54 91 17,600 — — — — 

12/13/1995 09:30 EST 111,000 39 89 11,800 111,000 63 94 18,800 

01/03/1996 12:00 EST 161,000 151 87 65,500 161,000 178 89 77,300 

01/17/1996 11:00 EST 148,000 101 80 40,300 — — — — 

01/31/1996 10:00 EST 272,000 567 63 416,000 272,000 608 74 446,000 

02/14/1996 11:00 EST 288,000 291 46 227,000 288,000 306 65 238,000 

02/29/1996 10:00 EST 185,000 145 76 72,300 — — — — 

03/13/1996 11:00 EST 251,000 229 61 155,000 251,000 262 74 178,000 

03/26/1996 11:00 EST 244,000 185 57 122,000 244,000 239 73 157,000 

04/10/1996 14:04 EDT 311,000 226 50 189,000 311,000 257 65 215,000 

04/28/1996 11:00 EDT 241,000 — — — — — — — 

05/08/1996 11:00 EDT 335,000 292 75 264,000 335,000 319 82 288,000 

05/23/1996 15:00 EDT 411,000 259 60 287,000 411,000 235 71 260,000 

06/04/1996 11:00 EDT 422,000 172 43 195,000 422,000 164 56 187,000 

06/20/1996 10:00 EDT 404,000 191 66 208,000 404,000 210 74 229,000 

07/02/1996 10:30 EDT 324,000 157 83 137,000 324,000 185 88 162,000 

07/17/1996 11:00 EDT 173,000 144 89 67,400 — — — — 

07/31/1996 11:00 EDT 184,000 104 89 51,700 184,000 134 93 66,700 

08/15/1996 11:00 EDT 179,000 90 86 43,600 — — — — 

08/28/1996 11:00 EDT 126,000 103 93 35,000 — — — — 

09/11/1996 11:00 EDT 109,000 81 93 23,900 — — — — 

09/25/1996 11:00 EDT 107,000 55 88 15,800 — — — — 

10/09/1996 10:00 EDT 180,000 161 80 78,300 180,000 202 88 98,300 

10/22/1996 11:00 EDT 99,000 64 95 17,100 — — — — 

11/06/1996 11:00 EST 174,000 136 75 63,900 — — — — 

11/20/1996 11:00 EST 283,000 250 70 191,000 283,000 294 76 225,000 

12/04/1996 11:30 EST 345,000 544 73 507,000 345,000 581 78 541,000 

12/18/1996 11:00 EST 397,000 285 58 306,000 397,000 310 71 333,000 

01/16/1997 11:00 EST 283,000 153 67 117,000 283,000 187 77 143,000 

01/30/1997 11:00 EST 278,000 378 67 284,000 290,000 422 72 331,000 

02/13/1997 11:00 EST 400,000 274 51 296,000 400,000 301 69 325,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 167

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/26/1997 11:00 EST 359,000 630 57 611,000 359,000 681 66 660,000 

03/11/1997 11:00 EST 504,000 417 42 567,000 — — — — 

03/18/1997 11:30 EST 583,000 333 59 524,000 583,000 292 58 460,000 

03/27/1997 16:00 EST 616,000 173 43 287,000 616,000 209 52 348,000 

04/09/1997 11:00 EDT 593,000 166 39 265,000 593,000 180 59 288,000 

04/23/1997 11:00 EDT 407,000 180 57 198,000 421,000 146 68 166,000 

05/07/1997 11:00 EDT 368,000 360 58 358,000 368,000 351 64 349,000 

05/21/1997 11:00 EDT 314,000 — — — 314,000 241 74 204,000 

06/04/1997 11:00 EDT 273,000 215 75 159,000 273,000 270 84 199,000 

06/18/1997 10:30 EDT 383,000 144 67 149,000 383,000 209 78 216,000 

07/02/1997 11:00 EDT 365,000 118 68 116,000 365,000 185 86 182,000 

07/16/1997 10:00 EDT 205,000 154 83 85,300 — — — — 

07/31/1997 10:00 EDT 143,000 76 87 29,400 — — — — 

08/13/1997 12:00 EDT 124,000 — — — — — — — 

08/27/1997 12:00 EDT 131,000 78 91 27,400 — — — — 

09/10/1997 12:00 EDT 100,000 39 100 10,500 — — — — 

09/24/1997 12:00 EDT 87,300 40 95 9,410 — — — — 

10/08/1997 10:00 EDT 96,000 47 100 12,200 — — — — 

10/22/1997 11:00 EDT 76,000 48 100 9,750 — — — — 

11/05/1997 11:00 EST 101,000 62 95 16,900 — — — — 

11/18/1997 11:30 EST 115,000 59 93 18,200 — — — — 

12/03/1997 09:30 EST 107,000 101 97 29,200 — — — — 

12/16/1997 11:00 EST 157,000 113 88 48,000 — — — — 

01/07/1998 11:30 EST 223,000 394 58 237,000 223,000 412 64 248,000 

01/28/1998 11:00 EST 422,000 548 43 624,000 422,000 524 53 597,000 

02/04/1998 10:30 EST 306,000 545 46 450,000 306,000 533 53 440,000 

02/18/1998 09:30 EST 310,000 457 43 382,000 310,000 847 28 709,000 

03/03/1998 10:00 EST 359,000 393 39 381,000 359,000 439 46 425,000 

03/18/1998 11:00 EST 348,000 311 47 292,000 348,000 364 55 342,000 

04/01/1998 11:00 EST 397,000 403 51 432,000 39,700 480 59 51,400 

04/14/1998 11:00 EDT 380,000 413 60 424,000 38,000 480 66 49,200 

05/05/1998 11:00 EDT 408,000 268 34 295,000 408,000 354 51 390,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
168 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/13/1998 11:00 EDT 436,000 207 38 244,000 436,000 265 53 312,000 

05/27/1998 09:30 EDT 407,000 174 36 191,000 407,000 222 51 243,000 

06/11/1998 11:00 EDT 208,000 203 81 114,000 208,000 255 86 143,000 

06/30/1998 11:30 EDT 322,000 470 84 409,000 322,000 516 87 449,000 

07/13/1998 11:30 EDT 311,000 278 80 233,000 311,000 342 84 287,000 

07/22/1998 09:00 EDT 274,000 265 75 196,000 274,000 345 81 255,000 

07/28/1998 13:00 EDT 215,000 249 91 145,000 215,000 325 93 188,000 

08/05/1998 14:30 EDT 188,000 163 85 82,800 188,000 231 90 117,000 

08/12/1998 11:00 EDT 188,000 182 84 92,400 188,000 237 89 121,000 

08/19/1998 11:00 EDT 182,000 139 85 68,300 182,000 206 90 101,000 

08/26/1998 10:00 EDT 148,000 155 86 61,800 148,000 230 91 92,000 

09/09/1998 10:00 EDT 99,500 — — — 99,000 165 97 44,000 

09/15/1998 12:00 EDT 101,000 79 97 21,700 101,000 185 100 50,000 

09/24/1998 10:00 EDT 76,000 52 93 10,700 76,000 132 98 27,000 

11/04/1998 10:30 EST 140,000 153 95 57,600 140,000 253 98 96,000 

11/18/1998 11:30 EST 213,000 300 80 172,000 213,000 360 86 207,000 

12/02/1998 11:00 EST 128,000 119 90 41,000 128,000 193 95 68,000 

12/15/1998 11:00 EST 200,000 472 74 255,000 200,000 506 77 273,000 

01/06/1999 10:00 EST 204,000 — — — 204,000 423 74 233,000 

01/20/1999 12:00 EST 243,000 282 60 185,000 243,000 411 73 269,000 

02/03/1999 10:30 EST — — — — 3432,000 3477 366 3557,000 

02/03/1999 10:31 EST 432,000 277 34 323,000 432,000 495 63 577,000 

02/17/1999 11:30 EST — — — — 3509,000 3265 352 3364,000 

02/17/1999 11:31 EST 509,000 411 67 565,000 509,000 272 51 374,000 

03/11/1999 11:00 EST — — — — 3269,000 3230 374 3167,000 

03/11/1999 11:01 EST 269,000 184 64 134,000 269,000 237 73 172,000 

03/23/1999 11:30 EST — — — — 34,090,000 3322 351 33,550,000 

03/23/1999 11:31 EST 409,000 284 43 314,000 24,090,000 324 51 23,580,000 

04/14/1999 14:00 EST 280,000 189 68 143,000 280,000 239 75 181,000 

04/21/1999 09:30 EST 273,000 125 80 91,800 273,000 172 86 126,000 

05/11/1999 11:30 EST — — — — 3386,000 3347 378 3362,000 

05/11/1999 11:31 EST 386,000 295 72 308,000 386,000 355 77 370,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 169

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/26/1999 10:00 EDT 301,000 157 77 128,000 301,000 224 84 182,000 

06/09/1999 09:30 EDT 270,000 284 88 207,000 270,000 369 91 269,000 

07/13/1999 10:00 EDT 256,000 290 88 200,000 256,000 369 91 255,000 

08/17/1999 10:00 EDT 128,000 92 93 31,700 — — — — 

09/08/1999 11:00 EDT 87,300 100 96 23,700 87,000 471 30 111,000 

10/13/1999 10:00 EDT 72,900 53 92 10,400 72,900 169 96 33,300 

11/09/1999 10:00 EST 60,200 44 99 7,200 60,200 94 100 15,300 

12/06/1999 12:45 EST 77,600 54 97 11,300 77,600 95 99 19,900 

12/21/1999 09:30 EST 140,000 176 93 66,700 140,000 227 95 85,900 

01/05/2000 10:00 EST 66,600 46 100 8,260 66,600 107 100 19,200 

01/19/2000 10:00 EST 132,000 — — — 132,000 359 98 128,000 

02/02/2000 10:00 EST 77,600 — — — 77,600 401 100 83,900 

02/15/2000 11:15 EST 62,100 — — — 62,100 191 100 32,000 

03/02/2000 11:30 EST 273,000 489 78 360,000 273,000 528 81 390,000 

03/15/2000 11:00 EST 204,000 173 73 95,100 204,000 232 80 128,000 

04/05/2000 10:30 EDT 283,000 414 81 316,000 283,000 461 84 352,000 

04/19/2000 11:00 EDT 323,000 200 63 175,000 323,000 229 69 200,000 

05/04/2000 14:30 EDT 191,000 110 80 56,700 191,000 142 86 73,500 

05/24/2000 10:00 EDT 118,000 96 99 30,700 118,000 127 99 40,500 

06/07/2000 10:00 EDT 201,000 141 80 76,700 201,000 183 85 99,300 

07/19/2000 10:00 EDT 173,000 115 93 53,900 173,000 156 96 72,900 

08/09/2000 10:30 EDT 108,000 72 98 21,000 108,000 109 99 31,500 

09/13/2000 10:00 EDT 73,400 61 100 12,100 73,400 135 100 26,900 

10/11/2000 10:00 EDT 91,900 59 97 14,600 91,900 98 99 24,200 

11/15/2000 09:30 EST 91,500 151 96 37,400 91,500 230 93 56,700 

12/06/2000 11:00 EST 143,000 161 82 62,100 143,000 207 86 80,000 

12/20/2000 10:00 EST 102,000 71 87 19,500 102,000 107 92 30,000 

01/24/2001 11:00 EST 208,000 483 65 271,000 20,800 527 69 29,700 

01/30/2001 11:00 EST 182,000 274 70 135,000 182,000 301 73 147,000 

02/05/2001 14:00 EST 214,000 214 56 123,000 214,000 243 63 140,000 

02/21/2001 12:00 EST 315,000 615 72 523,000 315,000 670 74 571,000 

03/06/2001 12:00 EST 463,000 481 57 602,000 463,000 504 62 630,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
170 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/21/2001 10:30 EST 372,000 454 63 456,000 372,000 493 67 496,000 

04/04/2001 11:30 EDT 337,000 275 55 250,000 337,000 374 50 340,000 

04/18/2001 10:00 EDT 249,000 201 55 135,000 249,000 247 65 166,000 

05/03/2001 10:00 EDT 249,000 210 67 141,000 249,000 271 76 182,000 

05/16/2001 10:00 EDT 208,000 121 69 67,900 208,000 160 79 89,500 

06/13/2001 10:00 EDT 275,000 173 67 128,000 275,000 213 74 158,000 

07/03/2001 11:00 EDT 215,000 273 89 159,000 215,000 306 91 177,000 

08/01/2001 09:30 EDT 109,000 113 95 33,200 109,000 152 97 44,600 

09/05/2001 10:00 EDT 128,000 147 98 50,700 128,000 210 99 72,400 

10/10/2001 10:00 EDT 72,700 93 99 18,200 72,700 141 100 27,700 

11/07/2001 09:30 EST 140,000 91 85 34,500 140,000 134 90 50,800 

12/04/2001 11:00 EST 183,000 312 71 154,000 183,000 351 75 173,000 

12/07/2001 09:30 EST 291,000 506 73 397,000 291,000 540 75 424,000 

01/02/2002 10:30 EST 406,000 281 50 308,000 406,000 306 54 335,000 

01/09/2002 11:00 EST 271,000 194 55 142,000 271,000 221 61 161,000 

01/23/2002 10:00 EST 155,000 144 64 60,300 155,000 172 70 72,000 

02/06/2002 11:00 EST 354,000 266 65 254,000 354,000 299 69 286,000 

02/20/2002 10:00 EST 267,000 168 71 121,000 267,000 259 59 187,000 

03/13/2002 10:00 EST 171,000 72 78 33,400 171,000 107 85 49,500 

03/28/2002 11:00 EST 372,000 347 87 348,000 372,000 394 88 395,000 

04/13/2002 10:00 EDT 458,000 199 53 246,000 458,000 222 58 275,000 

04/23/2002 10:30 EDT 357,000 261 60 251,000 357,000 273 71 263,000 

05/01/2002 10:00 EDT 319,000 175 71 151,000 319,000 197 74 169,000 

05/15/2002 09:30 EDT 368,000 176 69 175,000 368,000 203 73 202,000 

06/05/2002 10:30 EDT 451,000 153 45 186,000 451,000 175 52 213,000 

07/10/2002 10:00 EDT 146,000 87 92 34,100 146,000 127 95 50,100 

08/13/2002 11:00 EDT 95,300 52 95 13,300 95,300 143 99 36,800 

09/18/2002 11:00 EDT 81,600 62 100 13,600 81,600 166 100 36,600 

10/09/2002 10:00 EDT 156,000 145 88 61,100 156,000 193 83 81,300 

11/05/2002 11:00 CST 145,000 258 90 101,000 145,000 313 92 122,000 

12/04/2002 10:00 CST 131,000 62 79 22,000 131,000 166 92 59,000 

12/18/2002 10:00 CST 120,000 63 93 20,300 120,000 127 98 41,200 

01/08/2003 10:00 CST 292,000 198 54 156,000 292,000 236 61 186,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 171

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/22/2003 09:45 CST 185,000 118 80 59,100 185,000 199 88 99,500 

02/05/2003 10:30 CST 100,000 74 97 20,000 100,000 182 99 49,200 

02/19/2003 10:00 CST 180,000 134 73 64,900 180,000 194 81 94,400 

03/04/2003 10:15 CST 413,000 365 44 407,000 413,000 420 51 469,000 

03/18/2003 10:00 CST 391,000 186 39 196,000 391,000 220 49 232,000 

04/02/2003 10:00 CST 247,000 114 69 76,200 247,000 164 78 109,000 

04/30/2003 09:30 CDT 189,000 113 83 57,400 189,000 202 91 104,000 

05/06/2003 10:30 CDT 200,000 115 82 62,300 200,000 157 87 85,000 

05/20/2003 12:45 CDT 361,000 259 68 252,000 — — — — 

06/11/2003 09:00 CDT 289,000 103 77 80,300 289,000 172 87 134,000 

07/08/2003 10:30 CDT 198,000 109 89 58,300 198,000 143 92 76,400 

08/06/2003 11:00 CDT 177,000 82 86 39,000 177,000 130 82 62,200 

09/16/2003 10:30 CDT 196,000 155 87 82,200 196,000 212 91 112,000 

10/08/2003 09:30 CDT 125,000 52 93 17,500 125,000 102 97 34,500 

11/05/2003 10:00 CST 88,400 49 97 11,700 88,400 91 99 21,600 

12/03/2003 10:00 CST 271,000 265 76 194,000 271,000 308 79 225,000 

12/16/2003 10:00 CST 204,000 128 78 70,500 204,000 188 85 103,000 

01/07/2004 10:00 CST 220,000 137 70 81,300 220,000 179 77 107,000 

01/13/2004 10:00 CST 242,000 150 64 98,000 242,000 214 75 140,000 

02/10/2004 09:30 CST 233,000 262 80 165,000 233,000 322 84 202,000 

02/18/2004 10:00 CST 347,000 269 50 252,000 347,000 323 58 302,000 

03/10/2004 09:30 CST 243,000 158 73 104,000 243,000 201 79 132,000 

03/24/2004 09:00 CST 375,000 225 61 227,000 375,000 277 68 281,000 

04/07/2004 10:00 CST 239,000 123 73 79,600 239,000 170 81 110,000 

04/28/2004 11:00 CST 247,000 177 80 118,000 247,000 227 85 151,000 

05/26/2004 10:00 CST 215,000 101 82 58,700 215,000 152 89 88,100 

06/08/2004 10:00 CST 309,000 266 87 222,000 309,000 322 89 268,000 

06/30/2004 12:00 CST 368,000 222 75 221,000 368,000 274 79 272,000 

07/13/2004 11:00 CST 317,000 113 77 96,800 317,000 173 85 148,000 

08/11/2004 09:30 CST 161,000 89 89 38,700 161,000 167 95 72,600 

09/08/2004 11:00 CST 158,000 113 94 48,400 158,000 177 97 75,200 

10/06/2004 11:00 CST 186,000 216 93 108,000 186,000 269 94 135,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
172 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/03/2004 12:00 CST 191,000 130 87 66,900 191,000 172 90 88,400 

12/01/2004 11:00 CST 280,000 231 74 175,000 280,000 281 79 213,000 

12/21/2004 11:30 CST 419,000 210 42 237,000 419,000 247 51 279,000 

01/04/2005 14:00 CST 308,000 106 60 88,000 308,000 137 70 114,000 

01/25/2005 13:00 CST 509,000 236 41 324,000 509,000 279 50 383,000 

02/09/2005 16:00 CST 473,000 149 37 190,000 473,000 195 52 248,000 

02/23/2005 10:30 CST 323,000 117 64 102,000 323,000 164 75 143,000 

03/09/2005 15:15 CST 322,000 112 56 97,400 322,000 179 73 155,000 

03/29/2005 10:30 CST 204,000 98 82 53,900 204,000 151 89 83,300 

04/13/2005 11:00 CST 316,000 176 68 150,000 316,000 223 75 190,000 

04/26/2005 10:00 CST 294,000 117 76 92,700 294,000 169 83 135,000 

05/10/2005 12:00 CDT 231,000 170 86 106,000 231,000 231 90 144,000 

05/24/2005 11:30 CDT 139,000 69 89 26,000 139,000 138 95 51,500 

06/08/2005 11:15 CDT 135,000 85 99 30,900 135,000 147 100 53,500 

07/19/2005 11:00 CDT 129,000 71 97 24,500 129,000 144 99 50,000 

08/17/2005 11:00 CDT 75,100 53 95 10,800 75,100 153 90 31,000 

09/14/2005 11:00 CDT 117,000 76 95 24,100 117,000 149 98 47,200 

10/05/2005 11:00 CDT 82,500 79 100 17,500 82,500 140 100 31,100 

11/08/2005 14:30 CST 76,700 42 100 8,590 76,700 85 100 17,500 

12/07/2005 11:30 CST 74,500 51 98 10,200 74,500 103 100 20,800 

12/21/2005 10:30 CST 92,800 98 99 24,500 92,800 134 100 33,500 

01/11/2006 12:00 CST 101,000 50 95 13,500 101,000 94 98 25,700 

01/25/2006 15:00 CST 150,000 — — — 150,000 284 96 114,000 

02/08/2006 11:00 CST 250,000 228 85 154,000 249,000 259 87 175,000 

02/22/2006 11:00 CST 165,000 118 89 52,400 165,000 152 92 67,800 

03/08/2006 11:00 CST 133,000 121 97 43,300 133,000 157 98 56,200 

03/22/2006 11:00 CST 247,000 395 88 263,000 247,000 470 89 313,000 

04/05/2006 11:00 CST 194,000 126 86 66,200 194,000 166 90 87,100 

04/19/2006 10:30 CST 184,000 — — — 184,000 234 92 116,000 

05/03/2006 11:00 CST 218,000 150 88 88,300 218,000 198 91 116,000 

05/17/2006 11:00 CST 216,000 140 87 81,400 216,000 190 91 111,000 

06/07/2006 11:00 CDT 146,000 71 90 27,900 146,000 122 95 47,800 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 173

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/05/2006 11:00 CDT 94,400 63 99 16,100 94,400 115 100 29,300 

08/02/2006 11:00 CDT 81,900 51 99 11,300 81,900 107 100 23,700 

09/13/2006 11:00 CDT 70,700 46 99 8,800 70,700 118 100 22,500 

10/04/2006 11:00 CDT 162,000 208 92 91,100 162,000 257 94 112,000 

11/06/2006 15:00 CST 178,000 142 84 68,300 178,000 187 88 89,800 

12/06/2006 11:00 CST 196,000 134 78 70,900 196,000 168 83 88,900 

12/20/2006 11:00 CST 150,000 67 89 26,900 150,000 112 94 45,400 

01/10/2007 11:00 CST 289,000 226 72 176,000 289,000 260 76 203,000 

01/24/2007 11:00 CST 429,000 376 55 436,000 429,000 407 58 471,000 

02/14/2007 11:00 CST 224,000 136 70 82,100 224,000 167 75 101,000 

02/27/2007 11:00 CST 165,000 99 67 44,100 165,000 168 63 74,900 

03/14/2007 11:00 CST 288,000 270 81 210,000 288,000 320 84 248,000 

03/28/2007 11:00 CST 223,000 152 85 91,600 223,000 202 89 122,000 

04/11/2007 11:00 CST 292,000 168 72 132,000 292,000 206 78 162,000 

04/26/2007 11:00 CST 280,000 146 79 110,000 280,000 188 84 143,000 

05/09/2007 11:00 CDT 254,000 108 85 73,800 254,000 152 89 104,000 

05/23/2007 11:00 CDT 273,000 324 94 239,000 273,000 367 95 270,000 

06/06/2007 11:00 CDT 164,000 92 96 40,900 164,000 174 98 76,800 

07/11/2007 11:00 CDT 205,000 375 85 207,000 205,000 430 87 238,000 

08/01/2007 11:00 CDT 176,000 162 80 77,100 176,000 212 85 100,000 

09/12/2007 11:00 CDT 143,000 170 94 65,500 143,000 227 96 87,700 

10/03/2007 11:00 CDT 67,000 60 100 10,900 67,000 155 100 28,000 

11/07/2007 11:00 CST 131,000 152 92 53,700 131,000 203 94 71,900 

12/05/2007 11:00 CST 92,500 54 96 13,400 92,500 132 99 32,900 

12/19/2007 11:00 CST 181,000 208 58 102,000 181,000 263 67 128,000 

01/09/2008 12:00 CST 188,000 119 78 60,400 188,000 156 83 79,100 

01/23/2008 12:00 CST 240,000 292 72 189,000 240,000 344 76 223,000 

02/06/2008 12:00 CST 154,000 132 93 54,900 154,000 180 95 74,600 

02/20/2008 11:00 CST 328,000 367 72 325,000 328,000 393 74 348,000 

03/05/2008 11:00 CST 326,000 183 71 161,000 326,000 211 75 186,000 

03/18/2008 11:00 CDT 364,000 304 74 299,000 364,000 333 77 328,000 

04/03/2008 11:00 CDT 479,000 229 51 297,000 479,000 244 55 316,000 

04/19/2008 15:30 CDT 625,000 185 36 312,000 625,000 202 42 341,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
174 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/24/2008 13:00 CDT 435,000 139 58 163,000 435,000 168 66 198,000 

06/13/2008 11:00 CST 315,000 165 84 140,000 315,000 211 88 180,000 

06/24/2008 11:00 CST 343,000 242 83 224,000 343,000 300 83 278,000 

07/10/2008 11:00 CST 329,000 194 83 173,000 329,000 236 87 210,000 

08/06/2008 11:00 CST 181,000 131 92 63,900 181,000 169 94 83,000 

09/10/2008 11:00 CST 189,000 276 86 141,000 189,000 300 88 153,000 

10/01/2008 11:00 CDT 257,000 256 74 178,000 257,000 281 77 195,000 

11/05/2008 11:00 CST 97,700 88 97 23,200 97,700 165 99 43,500 

12/03/2008 11:00 CST 83,800 102 100 23,100 83,800 173 100 39,200 

12/15/2008 11:00 CST 154,000 286 91 119,000 154,000 318 92 132,000 

01/07/2009 11:00 CST 300,000 443 75 359,000 300,000 487 78 395,000 

01/28/2009 11:00 CST 181,000 130 89 63,700 181,000 180 92 88,100 

02/11/2009 11:00 CST 195,000 146 84 77,000 195,000 186 88 97,900 

02/25/2009 11:00 CST 273,000 252 79 186,000 273,000 284 81 209,000 

03/11/2009 11:00 CST 219,000 124 80 73,200 219,000 162 85 95,600 

03/25/2009 11:00 CST 273,000 483 92 356,000 273,000 511 93 377,000 

04/02/2009 11:00 CDT 303,000 181 76 148,000 303,000 211 79 173,000 

04/22/2009 11:00 CDT 351,000 153 70 145,000 351,000 188 76 179,000 

05/06/2009 09:00 CDT 351,000 132 76 125,000 351,000 160 80 152,000 

05/21/2009 09:00 CDT 509,000 226 55 311,000 509,000 250 59 344,000 

06/17/2009 14:00 CDT 357,000 133 60 128,000 357,000 193 62 186,000 

07/08/2009 11:15 CDT 251,000 185 88 125,000 251,000 209 90 142,000 

08/05/2009 11:00 CDT 181,000 114 94 55,600 181,000 152 96 74,200 

09/02/2009 11:00 CDT 135,000 89 96 32,400 135,000 132 98 48,200 

10/07/2009 11:00 CDT 208,000 133 83 74,500 135,000 156 86 56,800 

11/04/2009 11:00 CDT 370,000 — — — 370,000 392 59 392,000 

12/02/2009 11:00 CST 314,000 208 62 176,000 314,000 229 66 194,000 

12/17/2009 11:00 CST 307,000 212 51 176,000 307,000 241 57 200,000 

01/05/2010 11:00 CST 390,000 261 51 275,000 390,000 299 54 315,000 

01/19/2010 11:00 CST 255,000 208 53 143,000 255,000 229 58 158,000 

02/02/2010 09:30 CST 341,000 203 64 186,000 341,000 375 84 346,000 

02/17/2010 10:00 CST 463,000 273 43 341,000 463,000 451 68 564,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 175

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/03/2010 09:30 CST 314,000 269 51 228,000 314,000 464 73 393,000 

03/18/2010 09:30 CST 245,000 124 66 82,000 245,000 343 92 227,000 

03/30/2010 09:45 CST 365,000 215 69 212,000 365,000 405 87 399,000 

04/13/2010 09:45 CST 389,000 143 59 151,000 389,000 438 88 461,000 

04/28/2010 09:30 CST 237,000 — — — 237,000 408 96 261,000 

05/11/2010 09:30 CDT 314,000 — — — 314,000 486 94 412,000 

05/26/2010 09:30 CDT 390,000 — — — 390,000 483 89 509,000 

06/09/2010 09:30 CDT 320,000 — — — 320,000 353 95 305,000 

06/23/2010 09:45 CDT 268,000 — — — 268,000 714 99 516,000 

08/03/2010 09:45 CDT 228,000 — — — 228,000 527 99 325,000 

11/01/2010 12:00 CDT 103,000 66 99 18,400 103,000 189 100 52,500 

12/01/2010 11:00 CST 127,000 94 99 32,200 127,000 205 100 70,500 

12/22/2010 10:30 CST 131,000 108 95 38,200 131,000 212 98 74,900 

01/20/2011 10:30 CST 130,000 74 90 25,900 130,000 251 99 88,300 

02/15/2011 11:45 CST 156,000 91 86 38,300 156,000 293 97 123,000 

03/02/2011 09:15 CST 211,000 266 89 151,000 211,000 392 93 223,000 

03/16/2011 09:30 CST 388,000 290 66 303,000 388,000 335 72 351,000 

03/29/2011 09:15 CST 413,000 160 52 178,000 413,000 203 63 226,000 

04/12/2011 10:15 CST 359,000 127 70 123,000 359,000 200 81 194,000 

04/28/2011 09:30 CST 362,000 152 54 149,000 362,000 215 68 210,000 

05/13/2011 10:15 CST 617,000 251 41 419,000 617,000 295 50 491,000 

05/18/2011 10:30 CST 661,000 210 38 374,000 661,000 248 48 443,000 

06/03/2011 10:10 CST 570,000 92 40 142,000 570,000 134 60 206,000 

06/17/2011 10:30 CST 390,000 79 68 83,400 390,000 131 82 138,000 

07/18/2011 10:30 CST 273,000 125 90 92,100 273,000 186 95 137,000 

08/10/2011 10:45 CDT 169,000 112 96 51,200 169,000 217 100 99,100 

08/31/2011 09:45 CDT 134,000 54 96 19,500 134,000 162 99 59,000 

09/27/2011 09:45 CDT 115,000 52 95 16,100 115,000 158 99 49,000 

10/12/2011 10:15 CDT 105,000 49 97 13,700 105,000 178 100 50,500 

11/08/2011 10:15 CST 102,000 48 99 13,300 102,000 173 100 47,800 

12/06/2011 10:45 CST 256,000 — — — 256,000 1,540 97 1,070,000 

12/19/2011 10:15 CST 377,000 — — — 377,000 999 91 1,020,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
176 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/09/2012 10:45 CST 319,000 — — — 319,000 752 93 648,000 

02/28/2012 10:30 CST 207,000 150 84 83,600 — — — — 

03/12/2012 10:45 CST 217,000 — — — 217,000 849 98 497,000 

04/03/2012 10:30 CST 340,000 — — — 340,000 651 93 597,000 

04/17/2012 10:35 CDT 211,000 145 87 82,800 211,000 216 93 123,000 

05/01/2012 10:36 CDT 151,000 78 92 31,600 151,000 151 97 61,600 

05/17/2012 10:05 CDT 225,000 240 85 146,000 225,000 318 89 193,000 

05/31/2012 10:05 CDT 126,000 82 99 27,700 126,000 158 100 53,800 

06/26/2012 10:33 CDT 84,400 54 97 12,300 84,400 149 100 34,000 

07/10/2012 10:30 CDT 85,500 53 97 12,100 85,500 138 100 31,800 

07/25/2012 10:11 CDT 60,900 54 99 8,870 60,900 166 100 27,300 

08/08/2012 10:19 CDT 82,600 58 99 12,900 82,600 153 100 34,000 

08/27/2012 10:00 CDT 56,600 77 98 11,800 56,600 173 100 26,400 

09/11/2012 09:40 CDT 68,600 34 99 6,230 68,600 95 100 17,600 

09/25/2012 10:15 CDT 53,700 41 98 5,960 53,700 136 100 19,700 

10/25/2012 09:45 CDT 60,800 48 99 7,860 60,800 152 100 24,900 

12/05/2012 09:45 CST 62,700 27 96 4,640 62,700 142 100 24,000 

12/18/2012 09:45 CST 93,900 94 97 23,900 93,900 175 100 44,000 

01/23/2013 10:15 CST 286,000 368 73 284,000 286,000 407 76 314,000 

02/06/2013 10:20 CST 295,000 223 70 178,000 295,000 263 75 209,000 

02/28/2013 10:30 CST 243,000 150 84 98,100 243,000 199 89 131,000 

03/04/2013 10:00 CST 206,000 151 89 84,100 206,000 206 94 115,000 

03/19/2013 10:30 CDT 244,000 136 72 89,300 244,000 198 82 130,000 

04/08/2013 10:45 CDT 277,000 132 73 98,900 277,000 187 82 140,000 

05/01/2013 10:00 CDT 331,000 241 76 215,000 — — — — 

05/15/2013 10:00 CDT 394,000 125 58 133,000 — — — — 

05/30/2013 09:50 CDT 421,000 80 68 90,800 421,000 127 80 144,000 

06/13/2013 09:30 CDT 330,000 191 93 170,000 330,000 248 95 221,000 

06/26/2013 10:30 CDT 339,000 99 79 90,600 339,000 177 89 162,000 

07/10/2013 10:30 CDT 247,000 126 91 84,000 247,000 217 95 145,000 

07/24/2013 09:45 CDT 289,000 114 81 89,000 289,000 153 87 120,000 

08/07/2013 09:45 CDT 150,000 69 97 28,100 150,000 141 100 57,000 

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
Appendix 4 177

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

09/25/2013 10:15 CDT 86,800 54 100 12,600 86,800 131 100 31,000 

11/21/2013 10:45 CST 93,600 61 99 15,400 93,600 181 100 46,000 

12/11/2013 12:00 CST 139,000 102 98 38,300 — — — — 

01/22/2014 10:15 CST 246,000 131 71 86,800 — — — — 

02/05/2014 09:45 CST 161,000 95 96 41,400 — — — — 

02/27/2014 10:30 CST 178,000 86 93 41,300 — — — — 

03/19/2014 10:00 CST 231,000 106 83 66,200 — — — — 

04/02/2014 10:00 CST 223,000 191 90 115,000 — — — — 

04/17/2014 09:45 CDT 356,000 172 71 166,000 — — — — 

05/01/2014 10:15 CDT 268,000 121 82 87,400 — — — — 

05/29/2014 10:00 CDT 279,000 148 87 111,000 — — — — 

06/12/2014 09:45 CDT 217,000 103 87 60,500 — — — — 

06/24/2014 10:00 CDT 261,000 291 96 205,000 — — — — 

07/10/2014 10:00 CDT 228,000 249 95 153,000 — — — — 

07/24/2014 10:15 CDT 225,000 181 97 110,000 — — — — 

08/06/2014 12:00 CDT 151,000 134 99 54,600 — — — — 

08/19/2014 10:00 CDT 116,000 47 100 14,600 — — — — 

09/04/2014 10:15 CDT 136,000 100 99 36,500 — — — — 

09/19/2014 08:15 CDT 138,000 187 99 69,600 — — — — 

11/20/2014 09:00 CST 126,000 62 93 21,100 — — — —

12/09/2014 08:30 CST 133,000 51 95 18,200 — — — —

01/06/2015 10:30 CST 212,000 271 88 155,000 — — — —

01/20/2015 08:30 CST 195,000 97 89 51,100 — — — —

02/03/2015 11:00 CST 120,000 66 100 21,300 — — — —

1

Original results for suspended-sediment discharge for 01/23/1990 through 07/24/1990 were misreported and should have been as follows: 01/23/1990, 

376,000; 02/09/1990, 517,000; 03/06/1990, 164,000; 03/20/1990, 486,000; 04/03/1990, 526,000; 04/17/1990, 492,000; 05/01/1990, 378,000; 05/15/1990, 

933,000; 05/18/1990, 722,000; 05/22/1990, 634,000; 05/25/1990, 634,000; 06/01/1990, 546,000; 06/05/1990, 514,000; 06/12/1990, 410,000; 06/26/1990, 

481,000; 07/10/1990, 314,000; and 07/24/1990, 134,000 short tons per day.

2

Due to data-entry errors, the original result for suspended-sediment discharge on 01/05/1994 should have been reported as 84,800 short tons per day; the 

original results for stream discharge and suspended-sediment discharge on 03/23/1999 11:30 should have been reported as 409,000 cubic feet per second and 

355,000 short tons per day; and the original results for stream discharge and suspended-sediment discharge on 03/23/1999 11:31 should have been reported as 

409,000 cubic feet per second and 358,000 short tons per day.

3

Two methods were used for the samples collected on 02/03/1999, 02/17/1999, 03/11/1999, 03/23/1999, and 05/11/1999. The results for the second sample in 

each pair are considered more reliable than are the results for the first sample.

Table 4–3. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Atchafalaya River at 

Simmesport, Louisiana (U.S. Geological Survey station 07381490).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers and the U.S. Geological Survey. The five-digit “pcode” below each constituent name 

uniquely identifies that constituent in the U.S. Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended 

sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in 

the original dataset or could not be corrected because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; 

CST, central standard time]
178 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/05/1989 11:15 CST 375,000 — — — — — — — 

10/16/1989 11:15 CST 356,000 95 91 91,300 348,000 92 96 86,400 

10/30/1989 11:15 CST 324,000 144 71 126,000 330,000 170 81 151,000 

11/13/1989 11:15 CST 261,000 130 88 91,400 259,000 167 94 117,000 

11/27/1989 11:15 CST 350,000 108 93 102,000 366,000 130 96 128,000 

12/11/1989 11:15 CST 280,000 76 96 57,700 280,000 104 98 78,600 

12/26/1989 11:15 CST 203,000 165 97 90,300 189,000 83 96 42,400 

01/09/1990 11:15 CST 290,000 364 91 285,000 301,000 407 93 331,000 

01/22/1990 11:15 CST 504,000 381 89 518,000 523,000 421 92 594,000 

02/08/1990 11:15 CST 764,000 401 75 827,000 825,000 420 78 937,000 

02/22/1990 11:15 CST 1,020,000 179 76 492,000 1,020,000 207 76 573,000 

03/05/1990 11:15 CST 1,110,000 107 75 318,000 1,040,000 126 80 354,000 

03/19/1990 11:15 CST 909,000 106 90 259,000 886,000 126 93 300,000 

04/02/1990 11:15 CDT 985,000 174 90 463,000 978,000 150 89 396,000 

04/16/1990 11:15 CDT 745,000 183 85 367,000 798,000 174 80 375,000 

04/30/1990 11:15 CDT 745,000 198 83 398,000 — — — — 

05/14/1990 11:15 CDT 900,000 328 88 798,000 930,000 378 90 948,000 

05/29/1990 11:15 CDT 1,060,000 187 86 537,000 952,000 331 55 850,000 

06/11/1990 11:15 CDT 1,220,000 99 89 325,000 1,080,000 121 92 354,000 

06/25/1990 11:15 CDT 965,000 232 76 604,000 884,000 258 85 615,000 

07/09/1990 11:15 CDT 651,000 490 90 862,000 636,000 496 92 852,000 

07/23/1990 11:15 CDT 450,000 201 80 244,000 471,000 195 87 247,000 

08/06/1990 11:15 CDT 410,000 181 88 200,000 412,000 197 91 219,000 

08/22/1990 11:00 CDT 320,000 163 89 141,000 330,000 174 93 155,000 

09/04/1990 11:00 CDT 329,000 135 86 120,000 341,000 163 90 150,000 

09/17/1990 11:00 CDT 315,000 111 85 94,600 325,000 118 90 103,000 

10/03/1990 11:00 CDT 265,000 331 24 237,000 276,000 258 34 192,000 

10/15/1990 11:00 CDT 290,000 205 68 161,000 299,000 308 44 249,000 

10/29/1990 11:00 CST 355,000 298 65 286,000 349,000 273 76 257,000 

11/13/1990 10:30 CST 283,000 121 65 92,200 277,000 152 67 114,000 

11/26/1990 11:00 CST 288,000 119 49 92,700 273,000 155 49 114,000 
Appendix 4 179

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/10/1990 12:30 CST 360,000 209 70 203,000 358,000 167 65 161,000 

12/27/1990 12:00 CST 665,000 474 83 850,000 — — — — 

01/16/1991 12:00 CST 1,260,000 176 76 596,000 1,230,000 171 78 567,000 

01/28/1991 12:30 CST 1,270,000 152 42 521,000 1,200,000 155 49 503,000 

02/11/1991 13:00 CST 725,000 221 53 433,000 745,000 211 61 424,000 

02/27/1991 12:30 CST 899,000 205 62 498,000 916,000 218 68 540,000 

03/11/1991 12:30 CST 1,000,000 229 30 618,000 1,020,000 209 42 575,000 

03/25/1991 12:30 CST 749,000 186 54 377,000 775,000 187 69 391,000 

04/08/1991 12:30 CDT 850,000 256 50 586,000 876,000 222 70 526,000 

04/22/1991 12:30 CDT 1,000,000 228 58 618,000 950,000 259 68 665,000 

05/08/1991 12:00 CDT 1,160,000 268 47 837,000 1,110,000 274 55 822,000 

05/20/1991 12:30 CDT 1,050,000 255 72 727,000 1,040,000 282 82 793,000 

06/03/1991 12:30 CDT 869,000 277 66 649,000 823,000 284 67 631,000 

06/17/1991 12:30 CDT 724,000 287 78 562,000 622,000 287 77 481,000 

07/01/1991 12:30 CDT 514,000 293 82 407,000 528,000 295 87 420,000 

07/17/1991 12:30 CDT 335,000 136 87 123,000 340,000 149 89 137,000 

07/29/1991 12:30 CDT 285,000 164 90 126,000 266,000 195 94 140,000 

08/12/1991 12:30 CDT 241,000 100 85 65,000 236,000 124 83 79,000 

08/26/1991 12:30 CDT 222,000 75 97 45,000 216,000 92 99 54,000 

09/11/1991 12:00 CDT 222,000 — — — 209,000 78 98 44,000 

09/24/1991 12:30 CDT 213,000 72 96 41,400 201,000 124 99 67,000 

10/07/1991 12:30 CDT 219,000 — — — 214,000 81 93 47,000 

10/23/1991 12:30 CDT 186,000 — — — 180,000 92 95 45,000 

11/04/1991 12:30 CST 329,000 295 94 262,000 347,000 276 93 258,000 

11/18/1991 12:30 CST 330,000 158 73 141,000 311,000 140 79 117,000 

12/02/1991 12:00 CST 440,000 264 77 313,000 456,000 238 79 292,000 

12/16/1991 12:30 CST 826,000 — — — 911,000 464 61 1,140,000 

12/30/1991 12:00 CST 756,000 211 52 431,000 — — — — 

01/13/1992 12:30 CST 653,000 230 42 406,000 667,000 219 47 395,000 

01/29/1992 13:30 CST 505,000 134 61 183,000 483,000 142 69 185,000 

02/10/1992 12:30 CST 428,000 — — — 423,000 121 77 139,000 

02/20/1992 12:30 CST 415,000 176 81 198,000 394,000 195 90 207,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
180 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/11/1992 12:30 CST 620,000 222 63 371,000 585,000 211 71 334,000 

03/23/1992 12:30 CST 745,000 318 68 640,000 766,000 295 72 610,000 

04/06/1992 12:30 CDT 685,000 — — — 661,000 285 77 508,000 

04/20/1992 12:30 CDT 415,000 124 86 138,000 428,000 129 89 149,000 

05/04/1992 12:30 CDT 624,000 498 85 839,000 588,000 514 87 815,000 

05/19/1992 12:30 CDT 386,000 106 83 110,000 391,000 128 81 135,000 

06/01/1992 12:30 CDT 321,000 84 82 73,100 301,000 82 91 66,400 

06/15/1992 12:30 CDT 440,000 150 88 178,000 420,000 188 92 213,000 

06/29/1992 12:30 CDT 417,000 122 81 137,000 401,000 96 89 104,000 

07/13/1992 12:30 CDT 357,000 155 94 149,000 354,000 157 95 150,000 

07/27/1992 12:30 CDT 488,000 231 90 304,000 495,000 190 93 254,000 

08/12/1992 12:30 CDT 590,000 461 93 734,000 574,000 427 93 661,000 

08/24/1992 12:30 CDT 392,000 178 93 188,000 387,000 208 94 217,000 

09/10/1992 12:30 CDT 291,000 130 93 102,000 296,000 164 93 131,000 

09/23/1992 12:30 CDT 299,000 193 89 156,000 296,000 186 89 149,000 

10/13/1992 12:30 CDT 266,000 163 75 117,000 260,000 173 80 121,000 

10/19/1992 12:30 CDT 203,000 132 79 72,500 209,000 141 82 1795,000 

11/02/1992 12:30 CST 229,000 88 91 54,500 255,000 108 89 74,300 

11/16/1992 12:30 CST 304,000 152 67 125,000 343,000 159 81 147,000 

11/30/1992 12:30 CST 631,000 391 57 665,000 714,000 400 63 771,000 

12/14/1992 12:30 CST 648,000 287 50 503,000 569,000 274 58 421,000 

12/30/1992 10:00 CST 816,000 327 80 721,000 891,000 367 84 882,000 

01/11/1993 12:30 CST 809,000 428 48 935,000 853,000 396 52 913,000 

01/25/1993 12:30 CST 888,000 239 45 573,000 938,000 253 53 642,000 

02/08/1993 11:30 CST 796,000 — — — 866,000 216 52 505,000 

02/22/1993 11:00 CST 597,000 197 60 317,000 628,000 221 63 375,000 

03/08/1993 10:00 CST 803,000 357 64 773,000 800,000 374 67 808,000 

03/22/1993 11:00 CST 958,000 — — — 932,000 273 71 686,000 

04/05/1993 11:30 CDT 973,000 287 49 754,000 914,000 268 60 662,000 

04/19/1993 11:00 CDT 1,150,000 212 58 658,000 1,050,000 209 62 592,000 

05/03/1993 12:30 CDT 1,150,000 187 38 580,000 1,040,000 183 49 514,000 

05/17/1993 12:30 CDT 1,190,000 128 49 410,000 1,030,000 160 52 445,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 181

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

06/01/1993 12:45 CDT 1,010,000 177 68 484,000 851,000 267 60 615,000 

06/15/1993 10:30 CDT 665,000 208 73 374,000 653,000 237 80 417,000 

06/28/1993 12:30 CDT 701,000 197 71 373,000 657,000 249 70 441,000 

07/12/1993 12:30 CDT 629,000 264 83 448,000 631,000 293 87 498,000 

07/21/1993 12:00 CDT 704,000 257 79 488,000 732,000 322 85 636,000 

07/26/1993 13:00 CDT 730,000 291 73 573,000 723,000 311 81 607,000 

07/28/1993 11:45 CDT 740,000 294 74 588,000 731,000 287 81 567,000 

08/02/1993 14:00 CDT 772,000 229 63 478,000 702,000 231 74 439,000 

08/04/1993 14:45 CDT 785,000 228 58 484,000 771,000 252 64 525,000 

08/09/1993 12:00 CDT 810,000 231 65 505,000 757,000 265 69 541,000 

08/12/1993 12:30 CDT 830,000 421 63 944,000 794,000 378 72 811,000 

08/16/1993 11:00 CDT 829,000 343 58 768,000 — — — — 

08/18/1993 11:30 CDT 822,000 243 59 539,000 782,000 224 70 474,000 

08/23/1993 12:30 CDT 798,000 200 56 432,000 779,000 199 65 419,000 

09/07/1993 10:30 CDT 593,000 194 83 310,000 585,000 222 87 351,000 

09/20/1993 11:30 CDT 485,000 214 78 280,000 496,000 367 57 492,000 

10/04/1993 11:30 CDT 625,000 267 76 451,000 645,000 296 81 515,000 

10/18/1993 13:00 CDT 616,000 208 54 346,000 594,000 198 67 318,000 

11/01/1993 12:00 CST 454,000 157 64 192,000 454,000 164 71 201,000 

11/15/1993 11:30 CST 352,000 255 83 243,000 352,000 270 87 256,000 

11/29/1993 12:00 CST 815,000 305 58 671,000 796,000 323 64 693,000 

12/23/1993 10:30 CST 804,000 270 37 586,000 790,000 260 48 555,000 

01/06/1994 12:00 CST 409,000 140 53 154,000 458,000 138 59 171,000 

01/20/1994 12:00 CST 572,000 343 47 529,000 657,000 285 55 506,000 

02/03/1994 11:00 CST 679,000 359 61 658,000 835,000 389 63 876,000 

02/17/1994 12:00 CST 872,000 342 30 806,000 955,000 291 44 751,000 

03/03/1994 11:00 CST 944,000 220 41 560,000 1,060,000 208 47 595,000 

03/17/1994 12:00 CST 1,030,000 260 25 722,000 1,100,000 290 28 860,000 

04/14/1994 08:00 CDT 911,000 161 33 396,000 980,000 156 39 412,000 

04/21/1994 14:30 CDT 980,000 165 38 437,000 992,000 175 39 468,000 

04/28/1994 15:30 CDT 1,060,000 191 32 548,000 1,100,000 190 43 564,000 

05/04/1994 12:30 CDT 1,120,000 166 28 502,000 1,060,000 237 26 680,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
182 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/12/1994 11:00 CDT 1,150,000 — — — 1,070,000 79 81 238,000 

05/19/1994 11:00 CDT 1,050,000 160 32 455,000 — — — — 

05/25/1994 12:00 CDT 956,000 131 48 337,000 903,000 142 55 345,000 

06/02/1994 12:00 CDT 627,000 125 82 211,000 569,000 135 89 208,000 

06/16/1994 10:30 CDT 408,000 156 85 172,000 425,000 183 89 210,000 

06/23/1994 12:00 CDT 364,000 109 91 107,000 339,000 138 94 127,000 

06/29/1994 12:00 CDT 353,000 124 91 119,000 333,000 158 93 142,000 

07/14/1994 11:00 CDT 395,000 192 94 204,000 356,000 251 96 241,000 

07/27/1994 13:00 CDT 393,000 — — — 379,000 423 93 433,000 

08/10/1994 12:00 CDT 321,000 79 88 68,800 305,000 109 91 90,000 

08/25/1994 09:00 CDT 238,000 92 92 59,000 — — — — 

09/08/1994 10:00 CDT 252,000 65 91 44,100 — — — — 

10/06/1994 12:00 CDT 205,000 51 95 28,200 225,000 68 98 41,000 

10/27/1994 10:00 CDT 268,000 160 91 115,000 — — — — 

11/10/1994 12:00 CST 282,000 161 91 123,000 311,000 171 91 143,000 

11/17/1994 11:00 CST 374,000 300 89 303,000 — — — — 

12/01/1994 10:00 CST 374,000 175 85 177,000 — — — — 

12/22/1994 11:30 CST 630,000 209 77 356,000 720,000 216 76 420,000 

12/29/1994 12:00 CST 497,000 148 79 198,000 524,000 155 74 219,000 

01/11/1995 12:00 CST 320,000 137 87 118,000 340,000 153 91 141,000 

01/26/1995 11:30 CST 698,000 400 67 754,000 836,000 427 71 964,000 

02/09/1995 12:00 CST 623,000 152 70 255,000 651,000 170 76 299,000 

02/23/1995 12:00 CST 410,000 161 85 178,000 465,000 191 84 240,000 

03/09/1995 12:30 CST 566,000 339 86 517,000 580,000 379 88 593,000 

03/22/1995 12:00 CST 808,000 250 66 546,000 877,000 306 75 725,000 

04/06/1995 13:00 CDT 462,000 119 84 148,000 494,000 162 89 216,000 

04/20/1995 11:30 CDT 428,000 110 84 127,000 — — — — 

05/04/1995 12:00 CDT 723,000 224 84 437,000 786,000 258 87 547,000 

05/17/1995 12:30 CDT 761,000 186 80 383,000 853,000 230 83 529,000 

06/01/1995 12:30 CDT 982,000 195 64 516,000 999,000 215 70 579,000 

06/15/1995 12:00 CDT 1,170,000 67 83 210,000 1,180,000 79 86 251,000 

06/29/1995 11:00 CDT 1,020,000 116 66 320,000 926,000 129 71 323,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 183

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/12/1995 14:00 CDT 689,000 170 95 317,000 708,000 175 96 335,000 

08/03/1995 12:00 CDT 361,000 110 92 107,000 356,000 128 94 123,000 

08/17/1995 12:00 CDT 485,000 227 92 297,000 445,000 241 94 290,000 

08/31/1995 12:00 CDT 332,000 100 91 89,400 340,000 116 95 106,000 

09/14/1995 12:00 CDT 220,000 75 95 44,500 223,000 108 97 65,000 

09/26/1995 12:00 CDT 221,000 64 94 38,100 242,000 98 98 64,300 

10/12/1995 12:00 CDT 209,000 — — — 220,000 119 99 71,000 

10/26/1995 12:00 CDT 244,000 — — — 244,000 123 95 81,200 

11/09/1995 12:00 CST 237,000 69 93 44,100 237,000 136 97 86,900 

11/22/1995 11:00 CST 377,000 132 78 135,000 — — — — 

12/06/1995 11:00 CST 286,000 64 79 49,100 — — — — 

12/14/1995 11:00 CST 248,000 58 73 39,100 — — — — 

01/18/1996 11:00 CST 344,000 141 75 131,000 — — — — 

02/01/1996 11:00 CST 660,000 517 68 921,000 — — — — 

02/15/1996 12:00 CST 640,000 191 62 330,000 640,000 205 68 345,000 

02/28/1996 11:00 CST 442,000 157 73 187,000 — — — — 

03/14/1996 11:00 CST 551,000 259 67 386,000 554,000 274 74 410,000 

03/28/1996 11:00 CST 564,000 259 76 394,000 563,000 255 80 388,000 

04/11/1996 11:30 CDT 630,000 180 61 306,000 604,000 208 72 340,000 

04/25/1996 13:00 CDT 488,000 365 90 481,000 488,000 420 93 554,000 

05/09/1996 12:00 CDT 782,000 372 80 784,000 — — — — 

05/22/1996 11:00 CDT 929,000 219 59 550,000 926,000 261 64 652,000 

06/06/1996 11:00 CDT 1,030,000 144 54 400,000 1,020,000 155 63 429,000 

06/19/1996 12:00 CDT 984,000 189 64 502,000 935,000 210 69 531,000 

07/10/1996 11:00 CDT 526,000 444 95 631,000 — — — — 

07/18/1996 11:00 CDT 403,000 139 92 152,000 388,000 163 95 171,000 

08/01/1996 08:15 CDT 441,000 184 81 219,000 462,000 204 88 254,000 

08/14/1996 11:00 CDT 424,000 118 82 135,000 — — — — 

08/29/1996 11:00 CDT 300,000 114 94 92,300 289,000 139 96 108,000 

09/12/1996 10:30 CDT 242,000 100 98 65,000 — — — — 

09/26/1996 10:30 CDT 261,000 59 94 41,300 — — — — 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
184 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/10/1996 11:30 CDT 403,000 142 84 155,000 414,000 200 91 223,000 

10/23/1996 11:00 CDT 230,000 81 91 50,200 — — — — 

11/07/1996 11:00 CST 422,000 134 75 152,000 — — — — 

11/21/1996 11:00 CST 637,000 254 73 437,000 610,000 287 80 473,000 

12/05/1996 11:15 CST 777,000 345 77 723,000 811,000 393 79 860,000 

12/19/1996 12:00 CST 865,000 196 65 458,000 933,000 228 74 573,000 

12/30/1996 12:00 CST 824,000 201 56 446,000 829,000 217 67 486,000 

01/15/1997 11:00 CST 636,000 132 76 226,000 596,000 199 76 320,000 

01/29/1997 12:00 CST 584,000 359 86 566,000 625,000 415 88 700,000 

02/12/1997 11:00 CST 835,000 254 63 572,000 912,000 297 67 730,000 

02/27/1997 11:00 CST 824,000 258 74 574,000 838,000 298 79 675,000 

03/12/1997 15:00 CST 1,200,000 209 71 676,000 1,180,000 291 71 927,000 

03/20/1997 15:00 CST 1,410,000 167 57 637,000 1,470,000 223 63 884,000 

03/28/1997 10:30 CST 1,470,000 99 58 391,000 1,450,000 145 73 569,000 

04/10/1997 11:30 CDT 1,300,000 — — — 1,220,000 123 61 406,000 

05/01/1997 12:00 CDT 910,000 259 73 637,000 969,000 310 80 812,000 

05/08/1997 11:00 CDT 863,000 186 76 433,000 846,000 241 83 549,000 

05/22/1997 11:30 CDT 734,000 162 81 321,000 739,000 233 86 464,000 

06/05/1997 12:30 CDT 625,000 213 81 360,000 630,000 309 89 525,000 

06/19/1997 10:30 CDT 817,000 142 70 314,000 773,000 194 82 406,000 

07/17/1997 11:30 CDT 475,000 — — — 449,000 242 94 294,000 

07/30/1997 11:00 CDT 322,000 107 83 92,700 — — — — 

08/14/1997 11:00 CDT 274,000 74 90 54,500 — — — — 

08/28/1997 10:00 CDT 318,000 105 85 90,400 — — — — 

09/11/1997 09:30 CDT 234,000 87 92 54,700 — — — — 

09/25/1997 10:00 CDT 199,000 73 96 39,100 — — — — 

10/09/1997 10:00 CDT 234,000 72 95 45,600 — — — — 

10/23/1997 10:30 CDT 202,000 70 95 38,200 — — — — 

11/06/1997 10:30 CST 227,000 93 85 57,200 — — — — 

11/19/1997 11:30 CST 271,000 80 72 58,700 — — — — 

12/04/1997 10:30 CST 264,000 112 76 79,800 — — — — 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 185

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/17/1997 13:00 CST 315,000 81 63 69,100 — — — — 

01/08/1998 09:00 CST 526,000 709 89 1,010,000 — — — — 

01/21/1998 11:00 CST 969,000 391 64 1,020,000 984,000 431 66 1,140,000 

02/03/1998 09:30 CST 765,000 192 69 397,000 732,000 259 69 512,000 

02/19/1998 11:00 CST 760,000 233 55 478,000 784,000 271 63 574,000 

03/04/1998 11:30 CST 831,000 228 52 511,000 881,000 277 63 658,000 

03/19/1998 12:00 CST 843,000 215 64 489,000 855,000 252 73 583,000 

04/02/1998 11:00 CST 965,000 265 63 690,000 948,000 308 69 789,000 

04/15/1998 12:00 CDT 914,000 365 81 901,000 880,000 416 85 987,000 

04/29/1998 12:30 CDT 915,000 191 56 472,000 907,000 231 68 567,000 

05/14/1998 10:30 CDT 1,070,000 139 42 402,000 1,010,000 203 63 551,000 

05/28/1998 11:00 CDT 885,000 152 46 362,000 818,000 213 70 470,000 

06/15/1998 11:00 CDT 549,000 258 69 383,000 574,000 300 78 465,000 

07/01/1998 11:00 CDT 741,000 414 86 828,000 727,000 477 90 937,000 

07/14/1998 10:30 CDT 740,000 328 79 656,000 732,000 384 84 758,000 

07/21/1998 09:00 CDT 654,000 — — — 561,000 374 72 566,000 

07/23/1998 11:30 CDT 621,000 288 86 483,000 612,000 354 86 585,000 

07/29/1998 11:30 CDT 476,000 255 90 328,000 484,000 322 89 421,000 

08/05/1998 10:00 CDT 405,000 160 82 175,000 381,000 262 81 270,000 

08/13/1998 12:00 CDT 421,000 167 89 189,000 397,000 251 89 270,000 

08/20/1998 11:00 CDT — — — — 2437,000 2210 289 2248,000 

08/20/1998 11:01 CDT 405,000 146 80 159,000 437,000 215 87 253,000 

08/27/1998 11:00 CDT 320,000 124 85 107,000 306,000 220 92 181,000 

09/10/1998 10:00 CDT 224,000 82 92 49,500 267,000 231 83 166,000 

09/14/1998 12:00 CDT 218,000 101 92 59,400 333,000 182 97 164,000 

09/23/1998 09:30 CDT 197,000 95 99 50,400 254,000 180 95 124,000 

11/05/1998 10:00 CST 302,000 194 86 158,000 354,000 267 91 256,000 

11/10/1998 11:00 CST 298,000 187 80 150,000 366,000 258 87 255,000 

12/03/1998 11:00 CST 305,000 153 75 126,000 350,000 213 85 201,000 

12/16/1998 12:00 CST 450,000 380 83 462,000 502,000 429 85 581,000 

01/07/1999 11:30 CST 450,000 — — — 469,000 422 82 534,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
186 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/21/1999 12:00 CST 550,000 421 65 626,000 569,000 440 72 675,000 

02/11/1999 11:00 CST 1,160,000 283 47 884,000 1,190,000 306 55 982,000 

02/24/1999 11:00 CST 1,020,000 237 51 649,000 979,000 305 63 805,000 

03/10/1999 11:30 CST 595,000 300 79 482,000 650,000 348 82 611,000 

03/24/1999 11:00 CST 921,000 245 44 609,000 927,000 294 53 736,000 

04/15/1999 11:30 CDT 658,000 166 76 294,000 629,000 212 77 360,000 

04/22/1999 11:30 CDT 625,000 167 71 281,000 618,000 201 79 336,000 

05/13/1999 11:30 CDT 890,000 275 75 661,000 828,000 339 80 758,000 

05/27/1999 11:30 CDT 737,000 198 78 393,000 648,000 262 86 458,000 

06/10/1999 11:00 CDT 580,000 263 88 411,000 618,000 374 83 623,000 

07/15/1999 11:00 CDT 590,000 396 90 630,000 571,000 487 88 750,000 

08/12/1999 12:00 CDT 306,000 140 84 116,000 285,000 230 91 177,000 

09/09/1999 13:00 CDT 198,000 99 87 53,000 206,000 163 94 90,500 

10/21/1999 11:00 CDT 175,000 90 82 42,700 174,000 124 88 58,000 

11/10/1999 11:00 CST 155,000 — — — 162,000 97 93 42,600 

12/08/1999 10:30 CST 200,000 87 82 47,100 202,000 148 87 80,500 

12/22/1999 10:00 CST 314,000 227 81 192,000 322,000 314 84 273,000 

01/06/2000 11:00 CST 156,000 83 83 35,000 161,000 131 89 57,000 

01/20/2000 10:00 CST 281,000 — — — 290,000 349 89 273,000 

02/03/2000 11:00 CST 177,000 — — — 187,000 206 92 104,000 

02/16/2000 13:00 CST 163,000 — — — 165,000 242 94 108,000 

03/08/2000 11:00 CST 621,000 341 69 571,000 612,000 372 73 615,000 

03/16/2000 11:00 CST 391,000 178 64 188,000 386,000 222 71 231,000 

04/06/2000 11:00 CDT 625,000 379 81 640,000 583,000 433 81 681,000 

04/20/2000 11:00 CDT 673,000 219 70 399,000 649,000 244 75 428,000 

05/04/2000 10:00 CDT 436,000 152 58 179,000 435,000 174 71 204,000 

05/25/2000 10:00 CDT 297,000 156 83 125,000 297,000 198 87 159,000 

06/08/2000 11:00 CDT 470,000 200 69 254,000 469,000 237 79 300,000 

07/24/2000 11:30 CDT 384,000 213 87 221,000 371,000 174 84 174,000 

08/10/2000 11:00 CDT 250,000 102 80 68,700 266,000 140 86 101,000 

09/14/2000 11:00 CDT 169,000 138 95 62,900 165,000 180 97 80,200 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 187

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/12/2000 11:00 CDT 196,000 79 85 41,700 192,000 117 88 60,800 

11/16/2000 11:00 CST 230,000 146 87 90,600 235,000 176 86 111,000 

12/04/2000 10:30 CST 337,000 190 81 173,000 339,000 230 85 211,000 

12/18/2000 08:30 CST 224,000 90 71 54,300 227,000 185 71 113,000 

01/25/2001 11:00 CST 337,000 398 85 362,000 346,000 442 87 413,000 

02/01/2001 11:00 CST 486,000 342 56 449,000 504,000 388 62 528,000 

02/07/2001 10:30 CST 474,000 219 63 280,000 472,000 269 72 343,000 

02/22/2001 12:30 CST 802,000 629 81 1,360,000 804,000 677 84 1,470,000 

03/07/2001 12:00 CST 1,110,000 322 70 965,000 1,110,000 352 75 1,050,000 

03/22/2001 12:30 CST 880,000 193 70 458,000 859,000 228 75 530,000 

03/22/2001 12:31 CST 880,000 217 64 514,000 — — — — 

04/05/2001 12:00 CDT 791,000 277 74 591,000 733,000 307 78 607,000 

04/16/2001 11:30 CDT 602,000 185 71 301,000 542,000 219 76 321,000 

05/02/2001 12:00 CDT 645,000 236 83 410,000 574,000 279 88 432,000 

05/17/2001 11:00 CDT 428,000 121 76 140,000 418,000 179 85 202,000 

06/21/2001 11:30 CDT 700,000 275 87 520,000 675,000 353 90 643,000 

07/05/2001 12:00 CDT 484,000 432 90 564,000 479,000 485 91 627,000 

08/02/2001 11:00 CDT 262,000 123 89 87,200 260,000 192 93 135,000 

09/06/2001 10:00 CDT 260,000 337 98 236,000 261,000 402 99 283,000 

10/11/2001 10:00 CDT 190,000 111 87 56,700 185,000 184 92 92,100 

11/08/2001 12:00 CST 320,000 123 71 106,000 320,000 174 80 150,000 

12/05/2001 12:30 CST 508,000 708 83 971,000 535,000 796 83 1,100,000 

12/08/2001 15:00 CST 681,000 574 83 1,060,000 680,000 615 84 1,130,000 

12/19/2001 12:00 CST 740,000 232 75 462,000 700,000 269 77 514,000 

01/10/2002 12:00 CST 611,000 181 77 298,000 572,000 227 80 350,000 

01/24/2002 11:00 CST 351,000 135 70 128,000 352,000 219 75 208,000 

02/11/2002 13:00 CST 925,000 229 78 572,000 841,000 256 82 582,000 

02/25/2002 11:00 CST 558,000 148 69 224,000 528,000 196 77 280,000 

03/14/2002 10:00 CST 418,000 90 86 101,000 427,000 144 91 166,000 

03/27/2002 11:00 CST 860,000 271 87 629,000 817,000 316 90 697,000 

04/11/2002 12:00 CDT 1,100,000 153 56 455,000 1,100,000 185 63 548,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
188 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

04/24/2002 12:00 CDT 862,000 162 61 377,000 810,000 197 69 431,000 

05/02/2002 12:00 CDT 786,000 228 74 484,000 758,000 264 75 540,000 

05/16/2002 12:30 CDT 832,000 164 77 368,000 855,000 188 79 435,000 

06/06/2002 11:00 CDT 1,090,000 98 56 286,000 992,000 128 65 343,000 

07/11/2002 10:00 CDT 354,000 108 71 103,000 334,000 159 80 143,000 

08/15/2002 11:00 CDT 216,000 118 86 68,900 213,000 161 90 92,200 

09/19/2002 11:00 CDT 181,000 81 91 39,600 185,000 151 95 75,400 

10/17/2002 11:00 CDT 302,000 176 81 143,000 303,000 215 84 176,000 

11/06/2002 11:00 CST 359,000 589 88 571,000 — — — — 

12/05/2002 10:00 CST 312,000 125 53 105,000 325,000 180 67 158,000 

12/19/2002 10:00 CST 304,000 112 48 91,800 318,000 167 66 144,000 

01/09/2003 13:15 CST 680,000 208 49 382,000 702,000 253 58 439,000 

01/21/2003 10:15 CST 452,000 181 60 221,000 434,000 280 74 329,000 

02/03/2003 11:00 CST 253,000 119 73 81,300 265,000 206 85 148,000 

02/20/2003 11:00 CST 430,000 264 59 307,000 435,000 330 67 387,000 

03/03/2003 12:00 CST 935,000 365 57 922,000 1,010,000 422 62 1,080,000 

03/21/2003 12:30 CST 759,000 171 56 350,000 697,187 211 68 407,000 

04/03/2003 09:30 CST 588,000 160 62 254,000 561,000 210 74 319,000 

04/18/2003 10:30 CST 447,000 195 64 235,000 450,000 309 78 376,000 

05/08/2003 10:30 CST 464,000 123 64 154,000 457,000 189 77 234,000 

05/23/2003 15:00 CST 918,000 228 65 565,000 870,000 275 74 647,000 

06/19/2003 12:00 CST 614,000 170 71 282,000 640,000 224 81 388,000 

07/17/2003 11:00 CDT 367,000 112 67 111,000 367,000 200 81 199,000 

08/07/2003 10:30 CDT 407,000 106 66 117,000 394,000 165 79 175,000 

09/22/2003 11:00 CDT 330,000 110 80 98,000 312,000 244 86 205,000 

10/09/2003 10:00 CDT 291,000 82 65 64,700 291,000 136 79 107,000 

11/06/2003 10:00 CST 207,000 74 73 41,300 209,000 154 88 86,700 

12/04/2003 12:00 CST 589,000 323 66 514,000 548,000 389 72 575,000 

12/18/2003 10:00 CST 441,000 172 54 205,000 438,000 231 66 273,000 

01/08/2004 10:30 CST 483,000 170 55 222,000 477,000 223 66 287,000 

01/14/2004 10:00 CST 574,000 208 54 323,000 568,000 270 69 415,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 189

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/11/2004 12:00 CST 574,000 311 74 482,000 600,000 375 80 607,000 

02/19/2004 11:00 CST 826,000 265 57 591,000 862,000 320 53 745,000 

03/04/2004 11:00 CST 555,000 182 52 272,000 524,000 236 64 334,000 

03/17/2004 12:00 CST 810,000 387 79 847,000 790,000 455 81 971,000 

04/08/2004 11:00 CST 549,000 219 66 325,000 532,000 273 73 392,000 

04/22/2004 11:00 CST 485,000 160 67 209,000 458,000 211 75 260,000 

05/06/2004 11:00 CST 726,000 162 61 317,000 696,000 180 74 339,000 

05/20/2004 12:00 CST 639,000 285 83 492,000 619,000 311 87 521,000 

06/09/2004 13:00 CST 780,000 371 83 781,000 724,000 486 74 950,000 

06/17/2004 11:30 CST 849,000 244 74 559,000 784,000 290 79 614,000 

07/08/2004 12:00 CST 813,000 187 67 410,000 738,000 247 77 492,000 

08/12/2004 11:00 CST 370,000 102 75 102,000 327,000 169 85 149,000 

09/09/2004 11:00 CDT 379,000 183 77 187,000 365,000 236 82 233,000 

10/07/2004 10:30 CDT 414,000 267 85 298,000 403,000 315 88 343,000 

11/14/2004 12:00 CST 590,000 261 73 416,000 428,000 305 77 353,000 

12/02/2004 13:00 CST 662,000 233 55 417,000 698,000 260 62 491,000 

12/27/2004 11:30 CST 985,000 171 40 454,000 1,030,000 199 48 554,000 

01/13/2005 12:00 CST 872,000 228 55 537,000 871,000 263 64 619,000 

01/18/2005 12:30 CST 1,030,000 271 50 752,000 1,030,000 304 56 845,000 

02/03/2005 11:00 CST 1,230,000 225 29 746,000 1,140,000 221 30 682,000 

02/15/2005 15:00 CST 846,000 142 45 325,000 848,000 184 58 421,000 

03/09/2005 11:30 CST 772,000 157 44 327,000 755,000 209 58 426,000 

03/31/2005 11:00 CST 448,000 169 41 204,000 436,000 223 59 263,000 

04/14/2005 11:00 CST 734,000 230 53 456,000 711,000 285 61 548,000 

04/25/2005 11:00 CST 720,000 149 64 289,000 643,000 221 63 385,000 

05/11/2005 11:00 CST 529,000 213 67 305,000 519,000 273 74 382,000 

05/26/2005 11:00 CST 340,000 142 54 131,000 347,000 206 69 193,000 

06/09/2005 11:30 CST 325,000 103 75 90,500 320,000 159 84 137,000 

07/21/2005 11:00 CST 317,000 106 77 90,300 308,000 168 86 140,000 

08/18/2005 11:00 CST 173,000 73 82 34,100 174,000 183 73 85,700 

09/15/2005 11:00 CST 251,000 101 84 68,600 249,000 167 91 112,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
190 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/06/2005 11:00 CDT 219,000 194 90 115,000 223,000 241 92 145,000 

11/09/2005 11:00 CST 187,000 70 84 35,100 184,000 113 90 56,200 

12/08/2005 11:30 CST 197,000 81 73 42,900 201,000 118 82 63,800 

12/22/2005 12:30 CST 210,000 115 85 65,200 209,000 158 89 89,000 

01/12/2006 13:00 CST 249,000 90 70 60,800 258,000 138 80 96,100 

01/26/2006 11:00 CST 375,000 — — — 392,000 372 73 394,000 

02/09/2006 11:30 CST 548,000 295 66 436,000 532,000 330 70 473,000 

02/23/2006 11:00 CST 362,000 186 57 182,000 362,000 249 68 243,000 

03/09/2006 11:30 CST 304,000 154 90 126,000 293,000 225 88 178,000 

03/23/2006 11:00 CST 624,000 515 71 868,000 627,000 576 74 974,000 

04/06/2006 11:00 CST 433,000 159 70 185,000 406,000 204 77 224,000 

04/20/2006 12:00 CST 432,000 196 76 229,000 437,000 257 82 304,000 

05/04/2006 11:00 CST 526,000 206 70 293,000 521,000 250 76 351,000 

05/18/2006 11:00 CST 516,000 210 71 292,000 502,000 260 77 353,000 

06/08/2006 11:00 CDT 336,000 86 79 77,700 334,000 154 81 139,000 

07/06/2006 11:00 CDT 219,000 89 85 52,800 219,000 136 90 80,400 

08/03/2006 11:00 CDT 202,000 85 88 46,400 198,000 126 92 67,300 

09/14/2006 11:00 CDT 191,000 91 91 47,000 192,000 130 94 67,400 

10/05/2006 11:00 CDT 365,000 221 78 218,000 379,000 261 82 268,000 

11/08/2006 11:00 CST 442,000 243 59 289,000 448,000 283 65 342,000 

12/07/2006 11:00 CST 415,000 225 67 252,000 405,000 272 73 297,000 

12/21/2006 11:00 CST 354,000 120 60 114,000 356,000 161 71 155,000 

01/11/2007 11:00 CST 684,000 230 55 425,000 675,000 268 60 488,000 

01/25/2007 11:00 CST 912,000 294 51 724,000 888,000 369 50 885,000 

02/08/2007 11:00 CST 751,000 161 52 327,000 720,000 234 52 454,000 

02/26/2007 11:00 CST 387,000 161 60 168,000 383,000 206 69 213,000 

03/15/2007 11:00 CST 670,000 339 73 613,000 660,000 361 79 643,000 

03/29/2007 11:00 CST 536,000 232 74 336,000 546,000 279 80 411,000 

04/12/2007 11:00 CST 670,000 198 68 358,000 624,000 245 75 413,000 

04/25/2007 11:00 CST 620,000 188 65 315,000 627,000 228 72 386,000 

05/10/2007 11:00 CDT 616,000 245 75 407,000 607,000 295 82 484,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 191

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/24/2007 11:00 CDT 633,000 382 88 653,000 605,000 424 89 692,000 

06/07/2007 11:00 CDT 391,000 136 81 144,000 402,000 204 87 221,000 

07/12/2007 11:00 CDT 500,000 285 90 385,000 522,000 337 89 475,000 

08/02/2007 11:00 CDT 396,000 223 81 238,000 406,000 270 83 296,000 

09/13/2007 11:00 CDT 347,000 206 88 193,000 345,000 257 91 240,000 

10/04/2007 11:00 CDT 176,000 113 86 53,600 193,000 177 92 92,500 

11/08/2007 11:00 CST 295,000 181 76 144,000 296,000 302 86 241,000 

12/06/2007 11:00 CST 233,000 108 64 68,000 236,000 165 77 105,000 

12/20/2007 11:00 CST 420,000 358 57 406,000 464,000 412 63 516,000 

01/10/2008 11:00 CST 432,000 178 60 208,000 426,000 219 68 252,000 

01/24/2008 11:00 CST 556,000 291 66 437,000 568,000 334 70 512,000 

02/07/2008 11:00 CST 370,000 233 79 233,000 362,000 284 83 278,000 

02/21/2008 13:00 CST 765,000 429 65 885,000 807,000 465 68 1,010,000 

03/06/2008 09:00 CST 734,000 248 58 492,000 751,000 283 63 573,000 

03/19/2008 09:00 CDT 910,000 369 69 907,000 843,000 401 72 912,000 

03/31/2008 11:00 CDT 1,110,000 244 52 728,000 1,020,000 271 57 745,000 

04/20/2008 09:00 CDT 1,440,000 135 40 527,000 1,460,000 174 54 683,000 

05/17/2008 14:00 CDT 1,040,000 166 48 465,000 942,000 191 64 487,000 

05/29/2008 11:00 CDT 982,000 139 61 370,000 896,000 214 59 516,000 

06/25/2008 11:00 CDT 813,000 324 66 712,000 759,000 360 73 737,000 

07/09/2008 11:00 CDT 793,000 222 77 475,000 720,000 327 74 636,000 

08/07/2008 11:00 CDT 453,000 235 78 287,000 482,000 278 81 361,000 

09/11/2008 11:00 CDT 434,000 314 91 368,000 401,000 358 92 388,000 

10/02/2008 11:00 CDT 558,000 253 78 381,000 508,000 322 72 441,000 

11/06/2008 11:00 CST 240,000 99 76 64,400 244,000 173 86 114,000 

12/04/2008 11:00 CST 211,000 98 74 56,000 217,000 159 84 93,700 

12/16/2008 11:00 CST 307,000 407 87 337,000 319,000 460 89 396,000 

01/08/2009 11:00 CST 706,000 581 73 1,110,000 717,000 625 75 1,210,000 

01/29/2009 11:00 CST 389,000 210 58 221,000 372,000 247 64 248,000 

02/12/2009 11:00 CST 444,000 204 61 245,000 441,000 245 67 292,000 

02/26/2009 11:00 CST 630,000 295 67 501,000 603,000 373 72 607,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
192 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/12/2009 11:00 CST 497,000 180 57 241,000 473,000 220 65 281,000 

03/26/2009 11:00 CST 646,000 462 85 805,000 657,000 494 86 878,000 

04/01/2009 11:00 CST 697,000 236 74 444,000 694,000 300 79 562,000 

04/23/2009 11:00 CST 808,000 216 58 470,000 806,000 265 63 576,000 

05/07/2009 11:00 CST 820,000 219 49 485,000 790,000 259 57 553,000 

05/23/2009 13:30 CST 1,240,000 134 38 448,000 1,190,000 165 50 530,000 

06/19/2009 11:00 CST 754,000 137 62 279,000 711,000 189 73 363,000 

07/10/2009 11:00 CST 512,000 218 89 301,000 470,000 283 92 359,000 

08/06/2009 11:00 CDT 432,000 160 86 186,000 430,000 195 89 227,000 

09/03/2009 11:00 CDT 313,000 149 90 126,000 309,000 195 92 163,000 

10/01/2009 11:00 CDT 424,000 139 81 159,000 426,000 176 85 203,000 

11/05/2009 10:00 CST 868,000 285 66 667,000 880,000 397 45 943,000 

12/03/2009 11:00 CST 691,000 203 60 378,000 667,000 236 66 425,000 

12/18/2009 11:00 CST 708,000 224 56 427,000 771,000 259 63 497,000 

01/06/2010 11:00 CST 866,000 285 56 666,000 931,000 317 61 797,000 

01/28/2010 11:00 CST 644,000 276 64 479,000 675,000 302 68 551,000 

02/11/2010 11:00 CST 992,000 288 44 773,000 1,020,000 327 50 902,000 

02/25/2010 11:00 CST 881,000 141 46 336,000 855,000 175 57 403,000 

03/10/2010 11:00 CST 656,000 149 58 263,000 632,000 181 66 309,000 

03/24/2010 11:00 CST 705,000 505 81 961,000 718,000 537 82 1,040,000 

04/08/2010 11:00 CST 904,000 144 69 351,000 882,000 180 78 428,000 

04/22/2010 11:00 CST 700,000 177 67 334,000 677,000 221 75 404,000 

05/05/2010 11:00 CST 582,000 303 71 476,000 597,000 351 76 565,000 

05/20/2010 11:00 CDT 876,000 165 54 390,000 885,000 204 63 488,000 

06/17/2010 11:00 CDT 550,000 193 87 287,000 566,000 272 91 415,000 

07/01/2010 11:00 CDT 651,000 304 88 534,000 627,000 365 91 617,000 

08/05/2010 11:00 CDT 530,000 275 88 393,000 541,000 321 91 470,000 

09/01/2010 11:00 CDT 420,000 163 85 185,000 432,000 225 90 262,000 

10/07/2010 10:30 CDT 340,000 311 90 286,000 341,000 363 92 334,000 

11/10/2010 11:00 CST 242,000 67 88 43,800 231,000 185 93 115,000 

12/09/2010 11:00 CST 357,000 180 59 174,000 390,000 326 62 343,000 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 193

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/27/2010 11:00 CST 292,000 90 63 70,800 300,000 158 79 128,000 

01/13/2011 11:00 CST 336,000 197 55 178,000 372,000 377 46 378,000 

01/26/2011 11:00 CST 269,000 146 73 106,000 276,000 264 55 197,000 

02/14/2011 11:00 CST 364,000 137 53 134,000 361,000 180 66 175,000 

02/28/2011 13:00 CST 378,000 148 68 151,000 390,000 193 76 203,000 

03/10/2011 11:00 CST 800,000 508 77 1,100,000 786,000 548 79 1,160,000 

03/24/2011 11:00 CDT 927,000 209 48 522,000 940,000 243 56 616,000 

04/14/2011 11:00 CDT 782,000 196 52 413,000 750,000 234 60 473,000 

04/28/2011 11:00 CDT 837,000 160 53 362,000 845,000 191 62 437,000 

05/15/2011 13:30 CDT 1,500,000 156 47 628,000 1,500,000 179 54 722,000 

05/30/2011 12:00 CDT 1,480,000 144 29 575,000 1,420,000 164 41 630,000 

06/23/2011 10:30 CDT 784,000 169 57 357,000 758,000 203 65 415,000 

07/14/2011 11:00 CDT 672,000 193 76 351,000 653,000 232 80 410,000 

08/04/2011 11:00 CDT 410,000 138 79 153,000 437,000 190 85 224,000 

09/08/2011 11:00 CDT 330,000 186 89 166,000 336,000 306 74 278,000 

10/06/2011 10:00 CDT 280,000 99 71 75,000 290,000 153 82 119,000 

11/09/2011 10:30 CST 265,000 87 67 62,200 260,000 138 80 97,200 

12/01/2011 11:00 CST 541,000 285 72 416,000 536,000 317 75 458,000 

12/14/2011 11:00 CST 800,000 272 56 587,000 814,000 303 61 666,000 

01/05/2012 11:00 CST 760,000 205 49 420,000 779,000 274 48 576,000 

01/23/2012 10:00 CST 463,000 148 48 184,000 476,000 188 60 242,000 

02/06/2012 09:30 CST 771,000 266 48 554,000 785,000 296 54 629,000 

02/22/2012 11:30 CST 661,000 208 54 372,000 594,000 233 59 374,000 

03/05/2012 09:20 CST 415,000 123 49 138,000 412,000 154 60 171,000 

03/19/2012 09:30 CST 730,000 248 58 489,000 735,000 264 61 524,000 

04/12/2012 10:30 CDT 634,000 157 60 269,000 585,000 185 67 293,000 

04/26/2012 09:00 CDT 414,000 125 72 139,000 424,000 180 71 206,000 

05/10/2012 10:20 CDT 397,000 167 74 178,000 411,000 207 79 230,000 

05/24/2012 10:00 CDT 436,000 205 85 241,000 434,000 242 88 284,000 

06/07/2012 09:30 CDT 239,000 86 85 55,700 221,000 124 91 74,000 

07/05/2012 11:00 CDT 175,000 65 93 30,600 171,000 126 97 58,100 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
194 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/02/2012 11:45 CDT 143,000 91 86 34,900 142,000 133 91 50,700 

09/06/2012 11:00 CDT 156,000 101 93 42,600 159,000 140 95 60,300 

10/04/2012 10:00 CDT 205,000 177 95 98,100 217,000 218 96 127,000 

11/01/2012 10:30 CDT 152,000 104 86 42,500 161,000 155 91 67,000 

12/03/2012 12:45 CST 155,000 62 89 26,000 162,000 110 94 48,000 

01/17/2013 10:45 CST 562,000 472 74 716,000 560,000 482 75 729,000 

01/31/2013 10:30 CST 746,000 305 58 614,000 756,000 332 62 677,000 

02/07/2013 10:45 CST 640,000 265 58 459,000 604,000 289 62 470,000 

02/21/2013 09:30 CST 647,000 196 63 343,000 601,000 231 69 375,000 

03/07/2013 10:15 CST 472,000 190 60 242,000 449,000 225 66 273,000 

03/21/2013 10:00 CDT 620,000 357 63 597,000 631,000 398 67 679,000 

04/04/2013 12:00 CDT 698,000 224 56 423,000 679,000 245 60 449,000 

04/18/2013 09:45 CDT 559,000 218 69 329,000 537,000 250 73 362,000 

05/02/2013 10:50 CDT 850,000 309 77 709,000 837,000 336 79 758,000 

05/22/2013 11:45 CDT 980,000 138 36 364,000 999,000 168 49 453,000 

06/20/2013 11:45 CDT 840,000 170 54 385,000 832,000 198 61 445,000 

07/08/2013 10:30 CDT 576,000 169 84 262,000 557,000 192 86 289,000 

08/15/2013 10:00 CDT 304,000 158 85 130,000 317,000 182 88 156,000 

09/09/2013 10:30 CDT 246,000 88 83 58,100 255,000 113 88 78,000 

10/03/2013 09:45 CDT 210,000 78 88 44,000 208,000 110 92 62,000 

11/07/2013 10:00 CST 226,000 129 90 78,800 — — — — 

12/05/2013 10:30 CST 299,000 118 65 95,300 — — — — 

12/19/2013 11:00 CST 456,000 385 50 474,000 — — — — 

01/07/2014 12:00 CST 720,000 208 65 404,000 — — — — 

01/23/2014 09:45 CST 576,000 226 50 351,000 — — — — 

02/06/2014 09:30 CST 345,000 151 59 140,000 — — — — 

02/20/2014 09:45 CST 590,000 213 62 340,000 — — — — 

03/06/2014 10:00 CST 623,000 396 63 666,000 — — — — 

03/20/2014 10:00 CDT 537,000 201 56 291,000 — — — — 

04/03/2014 10:00 CDT 510,000 224 76 308,000 — — — — 

04/17/2014 09:30 CDT 800,000 410 74 886,000 — — — — 

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
Appendix 4 195

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/01/2014 09:45 CDT 658,000 192 72 341,000 — — — — 

05/15/2014 11:45 CDT 663,000 228 74 408,000 — — — — 

06/12/2014 10:00 CDT 505,000 158 66 215,000 — — — — 

07/21/2014 10:15 CDT 527,000 323 81 459,000 — — — — 

08/04/2014 10:30 CDT 347,000 156 78 147,000 — — — — 

09/11/2014 10:15 CDT 279,000 133 86 100,000 — — — — 

10/09/2014 10:30 CDT 246,000 134 84 88,800 — — — — 

1

Original result for suspended-sediment discharge on 10/19/1992 was miscalculated as 795,000 short tons per day and should have been reported as 79,500 short tons per day.

2

Two methods were used for the sample collected on 08/20/1998. The results reported for 11:01 are considered more reliable than are the results reported for 11:00.

Table 4–4. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Tarbert Landing, Mississippi (U.S. Geological Survey station 07295100).—Continued

[Discharge data were supplied by the U.S. Army Corps of Engineers (USACE) and were computed from stage read at noon at the Red River Landing gage 

(USACE 01100). Tarbert Landing is at river mile 306.3, about 4 miles upstream of Red River Landing. Some original results for discharge had been measured 

at other locations or were affected by data-entry errors. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. CDT, central daylight time; CST, central standard time]
196 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/13/1989 12:00 CDT 487,000 — — — — — — — 

11/09/1989 12:30 CST 359,000 — — — 359,000 101 95 97,700 

11/22/1989 11:15 CST 371,000 84 79 84,300 371,000 118 88 118,000 

12/08/1989 11:00 CST 456,000 566 96 696,000 456,000 603 97 743,000 

12/18/1989 13:00 CST 322,000 26 62 22,400 322,000 84 90 73,000 

01/05/1990 13:00 CST 293,000 541 98 428,000 293,000 595 98 471,000 

01/19/1990 12:30 CST 644,000 239 82 415,000 644,000 262 83 455,000 

02/05/1990 12:00 CST 883,000 299 77 712,000 883,000 307 78 732,000 

02/27/1990 12:00 CST E 1,330,000 167 67 598,000 1,270,000 189 68 649,000 

03/07/1990 12:30 CST E 1,420,000 141 57 542,000 1,280,000 162 65 560,000 

03/21/1990 12:00 CST 1,040,000 231 65 649,000 1,040,000 230 65 646,000 

04/06/1990 12:30 CDT 1,100,000 145 76 432,000 1,100,000 466 93 1,380,000 

04/16/1990 12:30 CDT 852,000 139 90 320,000 852,000 144 92 331,000 

05/03/1990 12:00 CDT 886,000 123 82 294,000 886,000 190 57 454,000 

05/31/1990 12:00 CDT E 1,320,000 176 82 626,000 1,080,000 198 86 578,000 

07/10/1990 12:00 CDT 809,000 367 93 801,000 809,000 386 93 843,000 

08/09/1990 11:30 CDT 435,000 164 93 193,000 435,000 192 94 226,000 

08/23/1990 11:45 CDT 359,000 129 99 125,000 359,000 138 100 134,000 

09/04/1990 12:30 CDT 400,000 108 99 116,000 400,000 110 100 118,000 

09/19/1990 12:30 CDT 298,000 92 88 74,000 298,000 124 93 99,600 

10/12/1990 13:30 CDT 291,000 124 95 97,500 291,000 128 98 100,000 

10/26/1990 12:45 CDT 404,000 137 83 149,000 404,000 177 77 193,000 

11/14/1990 08:00 CST 329,000 77 87 68,600 329,000 103 83 92,000 

11/29/1990 10:15 CST 256,000 63 93 43,800 256,000 90 95 62,500 

12/17/1990 09:00 CST 491,000 245 76 324,000 491,000 266 81 352,000 

12/26/1990 12:00 CST 730,000 527 76 1,040,000 730,000 530 79 1,040,000 

02/02/1991 11:10 CST E 1,430,000 156 64 603,000 1,040,000 176 71 493,000 

04/26/1991 12:10 CDT E 1,210,000 139 78 453,000 1,050,000 162 76 458,000 

05/10/1991 13:15 CDT E 1,290,000 134 81 465,000 967,000 149 88 389,000 
Appendix 4 197

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/24/1991 13:00 CDT E 1,110,000 175 82 526,000 912,000 201 82 494,000 

06/07/1991 12:25 CDT 953,000 253 82 651,000 953,000 283 86 728,000 

06/20/1991 12:50 CDT E 745,000 259 92 521,000 — — — — 

07/09/1991 11:25 CDT 469,000 217 93 274,000 469,000 226 95 286,000 

07/23/1991 11:15 CDT 432,000 — — — 432,000 138 87 160,000 

08/07/1991 11:55 CDT 297,000 74 90 59,500 297,000 76 94 61,000 

08/16/1991 10:35 CDT 261,000 73 93 51,100 261,000 101 97 71,000 

09/12/1991 10:15 CDT 242,000 96 88 63,000 242,000 92 81 60,000 

10/01/1991 11:05 CDT 248,000 54 100 36,400 248,000 70 100 47,000 

10/10/1991 12:25 CDT 226,000 — — — 226,000 89 99 54,000 

10/25/1991 10:40 CDT 195,000 — — — 195,000 88 98 46,000 

11/06/1991 12:10 CST 378,000 326 96 333,000 378,000 267 96 272,000 

11/22/1991 12:00 CST 383,000 — — — 383,000 223 91 230,000 

12/06/1991 10:50 CST 624,000 300 84 505,000 624,000 314 86 529,000 

12/18/1991 11:55 CST 1,110,000 331 71 991,000 1,110,000 295 72 883,000 

01/03/1992 12:55 CST 751,000 — — — 751,000 179 83 363,000 

01/17/1992 09:30 CST 737,000 131 67 261,000 737,000 173 76 344,000 

01/31/1992 13:05 CST 483,000 109 78 142,000 483,000 155 85 202,000 

02/19/1992 12:20 CST 418,000 186 93 210,000 418,000 167 95 188,000 

02/28/1992 11:55 CST 569,000 124 73 190,000 569,000 144 79 222,000 

03/13/1992 11:15 CST 684,000 169 72 313,000 684,000 202 80 374,000 

03/27/1992 11:25 CST 896,000 165 66 398,000 896,000 197 76 481,000 

04/10/1992 12:15 CDT 723,000 — — — 723,000 238 71 465,000 

04/24/1992 10:55 CDT 500,000 99 77 134,000 500,000 156 86 211,000 

05/13/1992 11:20 CDT 593,000 193 82 310,000 593,000 244 85 391,000 

05/22/1992 10:30 CDT 517,000 110 80 154,000 517,000 123 86 172,000 

06/05/1992 11:05 CDT 379,000 68 86 69,900 379,000 117 91 120,000 

06/19/1992 11:00 CDT 535,000 153 87 221,000 535,000 191 91 276,000 

07/02/1992 11:00 CDT 456,000 87 83 107,000 456,000 120 89 148,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
198 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/17/1992 10:40 CDT 413,000 92 87 103,000 413,000 120 91 133,000 

08/14/1992 11:20 CDT 737,000 344 89 685,000 737,000 452 93 899,000 

08/28/1992 12:10 CDT 482,000 521 95 678,000 482,000 649 97 845,000 

10/15/1992 11:45 CDT 298,000 111 88 89,200 298,000 132 92 106,000 

11/04/1992 15:00 CST 354,000 98 93 94,100 354,000 125 95 119,000 

11/18/1992 11:30 CST 491,000 177 56 235,000 491,000 204 66 270,000 

12/02/1992 11:00 CST 992,000 605 65 1,620,000 992,000 653 69 1,750,000 

12/16/1992 12:00 CST 681,000 290 43 534,000 681,000 269 63 495,000 

01/21/1993 14:00 CST E 1,130,000 391 44 1,190,000 1,280,000 414 54 1,430,000 

02/03/1993 10:30 CST 1,180,000 249 44 795,000 1,180,000 309 38 986,000 

02/16/1993 12:30 CST 682,000 197 59 362,000 682,000 223 65 411,000 

03/01/1993 10:00 CST 804,000 236 64 512,000 804,000 272 69 591,000 

03/15/1993 09:30 CST 1,120,000 358 70 1,080,000 1,120,000 381 75 1,150,000 

03/29/1993 11:00 CST E 1,210,000 258 53 843,000 1,160,000 267 59 839,000 

04/12/1993 13:00 CDT E 1,360,000 276 44 1,010,000 1,230,000 247 54 819,000 

06/21/1993 11:00 CDT 960,000 361 69 937,000 960,000 385 74 997,000 

07/07/1993 08:30 CDT E 833,000 335 76 753,000 — — — — 

07/19/1993 12:00 CDT 965,000 307 79 800,000 965,000 342 82 890,000 

08/04/1993 11:30 CDT 1,090,000 253 49 746,000 1,090,000 285 61 838,000 

08/16/1993 14:30 CDT E 1,160,000 333 51 1,040,000 1,150,000 366 62 1,130,000 

08/30/1993 12:00 CDT 927,000 187 64 468,000 927,000 293 55 734,000 

09/13/1993 11:00 CDT 741,000 187 85 374,000 741,000 198 86 397,000 

10/14/1993 13:00 CDT 963,000 — — — 963,000 255 65 663,000 

10/25/1993 12:00 CDT 619,000 160 65 268,000 619,000 191 56 320,000 

11/08/1993 15:00 CST 491,000 117 77 155,000 491,000 157 84 209,000 

11/22/1993 11:00 CST 804,000 398 70 864,000 804,000 419 73 910,000 

12/13/1993 11:00 CST 1,070,000 242 56 700,000 1,070,000 248 56 715,000 

01/10/1994 12:00 CST 506,000 171 38 234,000 506,000 181 48 247,000 

01/24/1994 12:00 CST 815,000 297 49 653,000 815,000 307 56 676,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 199

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/07/1994 12:30 CST 1,030,000 348 50 966,000 1,030,000 374 56 1,040,000 

03/07/1994 14:00 CST E 1,230,000 293 50 974,000 1,090,000 294 52 865,000 

03/21/1994 11:00 CST E 1,290,000 236 42 821,000 1,220,000 245 45 808,000 

04/04/1994 13:00 CDT E 1,160,000 179 47 559,000 1,140,000 178 51 548,000 

04/18/1994 12:00 CDT E 1,270,000 132 32 452,000 1,140,000 113 43 381,000 

06/07/1994 12:00 CDT 561,000 91 84 137,000 561,000 127 82 192,000 

06/21/1994 13:00 CDT 509,000 125 76 172,000 509,000 179 86 246,000 

07/07/1994 13:00 CDT 541,000 152 78 222,000 541,000 232 86 340,000 

07/21/1994 12:00 CDT 453,000 — — — 453,000 379 94 464,000 

08/02/1994 12:30 CDT 482,000 — — — 482,000 313 95 408,000 

08/16/1994 13:00 CDT 386,000 62 82 64,900 386,000 127 91 132,000 

09/13/1994 10:00 CDT 323,000 40 84 35,000 — — — — 

09/27/1994 10:00 CDT 256,000 44 92 30,300 — — — — 

10/12/1994 09:00 CDT 340,000 63 88 57,600 — — — — 

10/25/1994 10:30 CDT 308,000 131 95 109,000 — — — — 

11/22/1994 12:30 CST 486,000 243 85 319,000 — — — — 

12/06/1994 08:30 CST 583,000 214 65 337,000 — — — — 

12/20/1994 11:30 CST 774,000 275 60 575,000 — — — — 

01/24/1995 12:30 CST 848,000 427 61 977,000 848,000 447 64 1,020,000 

02/07/1995 12:30 CST 861,000 184 58 428,000 861,000 217 68 504,000 

03/07/1995 13:00 CST 640,000 170 67 294,000 640,000 269 81 465,000 

03/28/1995 13:00 CST 806,000 137 69 298,000 806,000 219 75 477,000 

04/11/1995 13:00 CDT 513,000 — — — 513,000 353 91 489,000 

04/25/1995 12:00 CDT 803,000 476 89 1,030,000 803,000 755 93 1,640,000 

05/09/1995 13:00 CDT 906,000 183 77 448,000 906,000 220 80 539,000 

06/06/1995 13:00 CDT E 1,460,000 160 57 629,000 1,190,000 180 63 579,000 

06/20/1995 11:30 CDT E 1,560,000 90 66 379,000 1,140,000 107 75 331,000 

07/18/1995 12:00 CDT 828,000 205 76 458,000 828,000 229 78 511,000 

08/01/1995 12:00 CDT 498,000 120 81 161,000 — — — — 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
200 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/15/1995 11:00 CDT 552,000 194 80 289,000 — — — — 

09/12/1995 12:00 CDT 309,000 80 90 66,700 — — — — 

10/03/1995 12:00 CDT 290,000 58 85 45,700 — — — — 

10/31/1995 12:00 CST 316,000 69 76 59,200 — — — — 

12/05/1995 12:00 CST 412,000 67 63 74,800 — — — — 

12/19/1995 12:15 CST 459,000 774 95 959,000 — — — — 

02/06/1996 11:00 CST 1,140,000 495 58 1,520,000 1,140,000 598 54 1,840,000 

02/27/1996 12:15 CST 658,000 253 49 449,000 658,000 277 61 492,000 

03/12/1996 11:00 CST 734,000 215 58 426,000 734,000 223 62 441,000 

04/02/1996 10:00 CST 889,000 205 66 492,000 889,000 252 75 604,000 

04/23/1996 12:00 CDT 581,000 324 82 508,000 — — — — 

05/07/1996 12:00 CDT 1,050,000 255 78 723,000 1,050,000 285 80 809,000 

05/21/1996 12:00 CDT E 1,250,000 248 52 836,000 1,280,000 285 61 982,000 

06/11/1996 11:00 CDT E 1,390,000 199 68 745,000 1,180,000 242 76 766,000 

06/25/1996 10:45 CDT E 1,270,000 194 54 666,000 1,120,000 220 65 666,000 

07/23/1996 11:00 CDT 493,000 132 74 176,000 — — — — 

08/06/1996 12:00 CDT 572,000 320 87 494,000 572,000 375 91 579,000 

08/27/1996 11:00 CDT 437,000 118 90 139,000 — — — — 

09/24/1996 11:00 CDT 329,000 69 92 61,500 — — — — 

10/08/1996 10:00 CDT 516,000 161 79 225,000 516,000 237 87 331,000 

11/05/1996 11:00 CST 505,000 169 72 230,000 — — — — 

12/03/1996 11:00 CST 956,000 415 74 1,070,000 956,000 541 71 1,400,000 

12/17/1996 12:00 CST 1,180,000 312 52 994,000 1,180,000 405 55 1,300,000 

01/28/1997 12:00 CST 676,000 273 68 498,000 676,000 344 74 628,000 

02/11/1997 12:00 CST 1,140,000 309 60 951,000 1,140,000 397 64 1,220,000 

03/04/1997 11:00 CST 1,060,000 443 82 1,270,000 1,060,000 554 841 1,590,000 

04/08/1997 12:00 CDT E 1,700,000 99 47 455,000 1,130,000 152 68 463,000 

04/29/1997 13:00 CDT E 1,120,000 265 77 802,000 1,030,000 326 84 906,000 

05/14/1997 13:00 CDT 1,010,000 197 65 538,000 1,010,000 259 87 704,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 201

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

06/03/1997 11:00 CDT 707,000 — — — 707,000 364 87 694,000 

06/17/1997 11:00 CDT 1,050,000 180 66 511,000 1,050,000 306 76 868,000 

07/08/1997 11:30 CDT 861,000 133 73 310,000 861,000 197 84 457,000 

08/05/1997 11:00 CDT 426,000 76 85 87,400 426,000 198 95 228,000 

08/19/1997 11:00 CDT 356,000 76 94 72,800 — — — — 

09/09/1997 11:00 CDT 342,000 — — — — — — — 

09/30/1997 11:00 CDT 314,000 76 93 64,700 — — — — 

10/21/1997 11:00 CDT 273,000 79 97 58,000 273,000 154 98 114,000 

12/02/1997 11:00 CST 336,000 105 92 95,200 336,000 157 94 142,000 

01/06/1998 13:00 CST 518,000 310 84 433,000 518,000 362 86 506,000 

01/27/1998 11:00 CST E 1,190,000 212 68 681,000 1,150,000 240 76 745,000 

02/10/1998 12:30 CST 674,000 143 61 261,000 674,000 186 72 338,000 

03/10/1998 12:00 CST 984,000 253 66 673,000 984,000 325 75 862,000 

03/31/1998 11:00 CST E 1,150,000 303 71 941,000 1,170,000 374 78 1,180,000 

04/21/1998 08:30 CDT E 1,170,000 216 69 683,000 1,090,000 352 63 1,030,000 

05/12/1998 11:30 CDT E 1,470,000 136 49 540,000 1,180,000 207 67 660,000 

07/07/1998 11:30 CDT 983,000 258 75 685,000 983,000 302 79 803,000 

08/11/1998 11:00 CDT 612,000 206 86 341,000 612,000 279 90 462,000 

08/25/1998 11:00 CDT 495,000 123 85 164,000 495,000 207 91 277,000 

11/03/1998 11:00 CST 405,000 207 85 227,000 405,000 305 87 330,000 

12/01/1998 11:00 CST 495,000 198 68 264,000 495,000 259 78 346,000 

01/05/1999 12:00 CST 505,000 — — — 505,000 484 91 660,000 

02/02/1999 11:00 CST E 1,120,000 564 68 1,710,000 1,080,000 597 70 1,750,000 

03/02/1999 11:00 CST 935,000 215 59 543,000 935,000 253 66 639,000 

04/13/1999 11:00 CDT 723,000 188 70 368,000 723,000 261 69 509,000 

04/20/1999 10:30 CDT 692,000 — — — 692,000 200 71 374,000 

05/18/1999 11:00 CDT E 1,200,000 279 61 904,000 999,000 322 67 867,000 

06/08/1999 13:00 CDT 750,000 355 82 718,000 750,000 421 85 852,000 

07/14/1999 13:00 CDT 744,000 433 87 870,000 744,000 509 90 1,020,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
202 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/24/1999 11:00 CDT 351,000 84 87 80,000 351,000 116 94 110,000 

09/13/1999 13:00 CDT 262,000 72 92 50,800 262,000 116 97 82,000 

10/26/1999 10:30 CDT 220,000 — — — 220,000 141 99 83,700 

11/30/1999 11:00 CST 198,000 47 100 25,100 198,000 112 100 59,900 

12/14/1999 10:00 CST 268,000 74 95 53,200 268,000 117 97 85,100 

01/04/2000 11:00 CST 232,000 74 92 46,400 232,000 123 96 77,400 

02/01/2000 10:30 CST 256,000 — — — 256,000 436 99 302,000 

03/21/2000 10:00 CST 416,000 140 79 157,000 416,000 185 81 208,000 

04/04/2000 11:00 CDT 776,000 511 87 1,070,000 776,000 538 89 1,130,000 

04/18/2000 11:00 CDT 933,000 256 64 644,000 933,000 266 72 670,000 

05/02/2000 12:00 CDT 576,000 145 64 225,000 576,000 168 72 261,000 

06/06/2000 12:00 CDT 592,000 151 68 241,000 592,000 230 79 368,000 

07/11/2000 11:00 CDT 742,000 291 82 583,000 742,000 322 85 645,000 

08/08/2000 11:00 CDT 361,000 103 89 101,000 361,000 138 92 135,000 

09/19/2000 11:30 CDT 216,000 73 95 42,500 216,000 114 97 66,600 

11/07/2000 10:30 CST 223,000 83 98 49,900 223,000 130 99 78,000 

11/21/2000 10:30 CST 337,000 124 82 113,000 337,000 167 87 152,000 

12/12/2000 11:00 CST 306,000 67 84 55,200 306,000 118 92 97,000 

01/09/2001 12:00 CST 322,000 100 91 87,200 322,000 132 94 114,000 

02/15/2001 11:00 CST 599,000 238 70 385,000 599,000 307 69 497,000 

03/20/2001 12:00 CST 902,000 192 81 466,000 902,000 226 84 551,000 

04/03/2001 12:00 CDT 893,000 240 76 578,000 893,000 276 80 666,000 

04/17/2001 11:30 CDT 640,000 159 69 274,000 640,000 224 79 386,000 

05/01/2001 10:30 CDT 701,000 238 85 450,000 701,000 266 87 503,000 

06/05/2001 11:30 CDT 894,000 232 79 559,000 894,000 290 83 700,000 

07/24/2001 10:15 CDT 416,000 101 90 113,000 416,000 131 93 147,000 

08/07/2001 10:00 CDT 415,000 117 88 131,000 415,000 153 91 171,000 

09/19/2001 10:30 CDT 265,000 66 96 47,100 265,000 151 99 108,000 

10/16/2001 10:30 CDT 316,000 197 99 168,000 316,000 261 100 223,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 203

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/06/2001 10:00 CST 446,000 133 74 160,000 446,000 181 81 218,000 

12/08/2001 12:00 CST 863,000 533 84 1,240,000 863,000 577 86 1,340,000 

01/08/2002 11:30 CST 702,000 175 71 332,000 702,000 259 70 490,000 

02/05/2002 11:00 CST 927,000 289 81 724,000 927,000 266 70 666,000 

03/05/2002 11:00 CST 492,000 90 79 120,000 492,000 131 86 175,000 

04/02/2002 10:30 CST E 1,220,000 198 79 653,000 1,140,000 232 82 717,000 

04/16/2002 10:30 CDT E 1,340,000 116 63 421,000 1,080,000 144 70 419,000 

05/07/2002 11:00 CDT 976,000 239 88 630,000 976,000 257 89 677,000 

06/04/2002 10:00 CDT E 1,470,000 83 78 329,000 1,160,000 107 83 338,000 

07/09/2002 10:00 CDT 461,000 112 80 140,000 461,000 180 87 223,000 

08/06/2002 11:00 CDT 352,000 81 93 77,400 352,000 133 91 126,000 

09/24/2002 11:00 CDT 273,000 108 98 79,400 273,000 184 99 136,000 

10/22/2002 11:00 CDT 454,000 161 75 197,000 454,000 201 80 247,000 

11/19/2002 11:00 CST 520,000 155 67 217,000 520,000 239 78 336,000 

12/10/2002 10:00 CST 380,000 95 75 97,900 380,000 149 84 152,000 

01/07/2003 11:00 CST 806,000 193 59 420,000 806,000 234 66 509,000 

02/04/2003 10:30 CST 320,000 106 86 91,300 320,000 170 92 147,000 

03/08/2003 11:00 CST E 1,240,000 261 52 873,000 1,220,000 310 59 1,020,000 

04/01/2003 10:30 CST 739,000 129 75 257,000 739,000 212 73 423,000 

04/19/2003 10:30 CST 597,000 164 68 265,000 597,000 226 77 364,000 

05/07/2003 10:30 CST 613,000 130 60 216,000 613,000 193 73 319,000 

06/03/2003 11:00 CST E 1,410,000 134 40 510,000 1,160,000 200 58 627,000 

07/22/2003 11:00 CDT 609,000 162 76 266,000 609,000 248 84 407,000 

08/05/2003 11:00 CDT 554,000 124 64 186,000 554,000 171 74 256,000 

09/17/2003 10:30 CDT 602,000 193 73 313,000 602,000 257 80 418,000 

10/07/2003 10:30 CDT 421,000 71 69 81,200 421,000 128 83 146,000 

11/04/2003 11:00 CST 301,000 57 90 46,400 301,000 99 94 80,100 

12/02/2003 10:30 CST 783,000 330 64 698,000 783,000 379 68 802,000 

01/23/2004 11:00 CST 973,000 246 62 647,000 973,000 302 67 794,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
204 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/06/2004 11:00 CST 688,000 778 92 1,450,000 — — — — 

03/02/2004 11:00 CST 633,000 143 75 244,000 633,000 196 82 335,000 

04/06/2004 10:00 CST 705,000 172 54 327,000 705,000 227 66 432,000 

04/21/2004 11:00 CST 638,000 150 72 258,000 638,000 197 79 340,000 

05/25/2004 11:00 CST 655,000 128 76 227,000 655,000 172 82 304,000 

06/15/2004 08:30 CST 1,040,000 291 83 817,000 1,040,000 341 86 955,000 

07/14/2004 11:00 CST 776,000 138 84 289,000 776,000 208 90 435,000 

08/10/2004 11:00 CST 518,000 107 70 150,000 518,000 185 83 259,000 

09/14/2004 11:00 CDT 412,000 174 94 193,000 412,000 229 95 255,000 

10/05/2004 10:30 CDT 638,000 258 83 445,000 638,000 304 85 523,000 

11/02/2004 10:30 CST 521,000 126 65 177,000 521,000 171 74 241,000 

12/08/2004 11:00 CST 1,060,000 290 67 829,000 1,060,000 368 63 1,050,000 

01/11/2005 12:00 CST 1,030,000 198 61 551,000 1,030,000 331 49 918,000 

01/27/2005 11:00 CST E 1,580,000 191 47 814,000 1,310,000 246 52 870,000 

02/10/2005 11:00 CST E 1,290,000 170 35 592,000 1,130,000 206 47 631,000 

02/17/2005 11:00 CST 939,000 135 46 343,000 939,000 179 59 453,000 

03/15/2005 11:15 CST 801,000 120 62 260,000 801,000 174 74 377,000 

04/19/2005 11:30 CST 1,020,000 160 57 442,000 1,020,000 199 66 550,000 

05/03/2005 11:00 CDT 636,000 134 64 231,000 636,000 190 75 326,000 

06/01/2005 11:30 CDT 578,000 269 89 419,000 578,000 329 91 513,000 

07/06/2005 11:30 CDT 415,000 119 89 133,000 415,000 185 93 208,000 

08/02/2005 11:30 CDT 301,000 71 94 57,600 301,000 131 97 107,000 

09/07/2005 12:00 CDT 410,000 153 90 170,000 410,000 218 94 241,000 

10/04/2005 11:00 CDT 307,000 182 97 151,000 307,000 273 98 226,000 

11/01/2005 11:00 CST 250,000 68 93 45,900 250,000 110 96 74,700 

12/13/2005 11:00 CST 354,000 105 73 101,000 354,000 142 80 135,000 

01/18/2006 11:00 CST 458,000 171 69 212,000 458,000 219 76 271,000 

02/14/2006 11:00 CST 660,000 219 80 391,000 660,000 280 78 500,000 

03/14/2006 11:00 CST 346,000 140 90 130,000 346,000 221 93 206,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 205

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

04/11/2006 11:30 CST 436,000 121 68 143,000 436,000 177 78 208,000 

04/25/2006 11:30 CST — — — — — — — — 

05/09/2006 11:00 CST 689,000 140 76 261,000 689,000 182 82 339,000 

06/14/2006 11:00 CST 455,000 89 68 110,000 455,000 141 80 173,000 

07/11/2006 11:00 CDT 349,000 76 87 72,000 349,000 129 93 121,000 

08/01/2006 11:00 CDT 293,000 82 89 64,700 293,000 137 94 108,000 

09/06/2006 11:00 CST 211,000 75 95 42,500 211,000 114 97 65,000 

10/03/2006 11:00 CDT 538,000 78 11 113,000 538,000 291 76 422,000 

11/07/2006 11:00 CDT 594,000 198 68 317,000 594,000 236 73 378,000 

12/12/2006 11:00 CST 596,000 147 67 236,000 596,000 205 66 329,000 

01/17/2007 11:00 CST 945,000 241 65 615,000 945,000 273 70 697,000 

02/06/2007 11:00 CST 1,000,000 177 52 477,000 1,000,000 210 60 568,000 

03/06/2007 11:00 CST 771,000 256 80 533,000 771,000 341 75 710,000 

04/04/2007 11:00 CST 863,000 213 73 496,000 863,000 263 79 614,000 

04/17/2007 11:00 CST 847,000 196 78 447,000 847,000 244 83 558,000 

05/01/2007 11:00 CST 928,000 182 73 455,000 928,000 239 80 598,000 

06/05/2007 11:00 CDT 486,000 144 81 188,000 486,000 205 87 268,000 

07/17/2007 11:00 CDT 614,000 323 92 535,000 614,000 385 93 639,000 

08/14/2007 11:00 CDT 324,000 132 96 115,000 324,000 193 97 169,000 

09/11/2007 11:00 CDT 424,000 211 89 242,000 424,000 260 91 298,000 

10/10/2007 11:00 CDT 239,000 91 96 58,400 239,000 185 86 119,000 

11/14/2007 11:00 CST 317,000 129 81 111,000 317,000 233 89 199,000 

12/11/2007 11:00 CST 345,000 81 68 75,600 345,000 174 66 162,000 

01/08/2008 11:00 CST 569,000 172 66 265,000 569,000 216 73 332,000 

02/12/2008 11:00 CST 645,000 213 68 371,000 645,000 275 67 478,000 

03/04/2008 11:00 CST 954,000 232 66 597,000 954,000 264 70 680,000 

04/01/2008 11:00 CDT E 1,480,000 203 59 811,000 1,220,000 256 58 842,000 

05/17/2008 11:00 CDT E 1,290,000 152 57 528,000 1,040,000 184 65 516,000 

05/28/2008 11:00 CDT E 1,290,000 157 57 548,000 1,070,000 199 67 577,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
206 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

06/10/2008 11:00 CDT 960,000 191 67 495,000 960,000 231 73 598,000 

07/08/2008 11:00 CDT 1,010,000 236 71 643,000 1,010,000 275 76 750,000 

08/12/2008 11:00 CDT 677,000 463 92 846,000 677,000 479 92 907,000 

09/09/2008 11:00 CDT 469,000 349 96 441,000 469,000 361 97 499,000 

10/15/2008 11:00 CDT 377,000 96 91 97,600 377,000 149 95 151,000 

11/12/2008 11:00 CST 317,000 132 91 113,000 317,000 204 94 175,000 

12/09/2008 11:00 CST 280,000 58 89 43,800 280,000 101 94 76,200 

01/13/2009 11:00 CST 868,000 343 70 803,000 868,000 390 74 914,000 

02/10/2009 11:00 CST 658,000 207 70 368,000 658,000 246 75 436,000 

03/10/2009 11:00 CST 685,000 149 72 276,000 685,000 182 77 336,000 

04/14/2009 11:00 CST 1,020,000 244 72 671,000 1,020,000 279 76 769,000 

04/28/2009 11:00 CDT 1,020,000 172 62 474,000 1,020,000 209 69 575,000 

05/24/2009 14:30 CDT E 1,590,000 109 52 466,000 1,140,000 145 64 448,000 

06/18/2009 14:30 CDT 846,000 120 72 274,000 846,000 164 79 374,000 

07/14/2009 11:00 CDT 545,000 147 84 217,000 545,000 184 87 271,000 

08/04/2009 11:00 CDT 526,000 156 91 222,000 526,000 197 93 280,000 

08/10/2009 11:00 CST — — — — 1685,000 1158 171 1293,000 

09/01/2009 10:30 CDT 453,000 99 86 121,000 453,000 148 91 181,000 

10/20/2009 11:00 CDT 949,000 404 74 1,040,000 949,000 431 76 1,100,000 

11/10/2009 11:00 CST E 1,110,000 232 73 694,000 1,070,000 259 77 750,000 

12/08/2009 11:00 CST 685,000 128 64 236,000 685,000 158 71 293,000 

01/29/2010 11:00 CST 872,000 243 69 572,000 872,000 286 69 673,000 

02/12/2010 11:00 CST E 1,240,000 215 51 721,000 1,180,000 246 58 786,000 

03/02/2010 11:00 CST 866,000 107 58 249,000 866,000 151 71 353,000 

04/06/2010 11:00 CST E 1,190,000 176 58 565,000 1,120,000 210 65 637,000 

04/20/2010 11:00 CST 972,000 176 63 461,000 972,000 214 70 562,000 

05/04/2010 11:00 CST 707,000 146 72 278,000 707,000 198 80 379,000 

06/08/2010 11:00 CDT 1,000,000 173 66 468,000 1,000,000 224 75 605,000 

07/07/2010 11:00 CDT 861,000 264 88 614,000 861,000 314 90 731,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 207

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/03/2010 11:00 CDT 761,000 276 91 568,000 761,000 323 89 663,000 

09/08/2010 11:00 CDT 456,000 135 91 166,000 456,000 189 94 233,000 

10/05/2010 10:30 CDT 486,000 284 90 373,000 486,000 327 92 429,000 

11/16/2010 11:00 CST 326,000 161 98 142,000 326,000 242 99 213,000 

12/07/2010 11:00 CST E 472,000 160 62 204,000 326,000 205 71 181,000 

01/12/2011 11:00 CST 484,000 155 62 203,000 484,000 252 78 330,000 

02/01/2011 11:00 CST 334,000 118 85 107,000 334,000 217 81 196,000 

03/01/2011 11:00 CST 639,000 265 76 457,000 639,000 333 81 575,000 

04/05/2011 11:00 CDT E 1,340,000 160 35 580,000 1,200,000 193 42 628,000 

04/19/2011 11:00 CDT 1,020,000 185 58 509,000 1,020,000 226 66 620,000 

05/03/2011 11:00 CDT E 1,350,000 151 54 550,000 1,200,000 175 61 568,000 

06/16/2011 11:00 CDT E 1,340,000 122 64 442,000 985,000 154 72 409,000 

07/12/2011 10:30 CDT 919,000 248 72 614,000 919,000 279 76 692,000 

08/03/2011 11:00 CDT 598,000 123 89 199,000 598,000 168 92 270,000 

09/07/2011 10:30 CDT 459,000 216 93 268,000 459,000 268 95 332,000 

10/05/2011 11:30 CDT 407,000 87 81 95,900 407,000 142 90 156,000 

11/08/2011 10:30 CST 358,000 70 71 67,900 358,000 114 83 110,000 

12/06/2011 11:00 CST 854,000 317 77 731,000 854,000 369 76 851,000 

01/11/2012 10:15 CST 952,000 172 46 443,000 952,000 208 55 534,000 

02/07/2012 09:45 CST 979,000 219 58 578,000 979,000 251 63 663,000 

03/07/2012 11:15 CST 520,000 120 46 168,000 520,000 163 60 229,000 

04/12/2012 13:15 CST 686,000 115 75 213,000 686,000 149 81 277,000 

04/25/2012 11:30 CST 516,000 126 73 176,000 516,000 178 82 247,000 

05/08/2012 11:15 CST 503,000 200 78 272,000 503,000 259 83 352,000 

06/12/2012 10:30 CST 319,000 87 91 75,000 319,000 162 96 140,000 

07/11/2012 10:45 CST 248,000 69 96 46,500 248,000 123 99 83,000 

08/07/2012 10:30 CST 241,000 82 96 53,100 241,000 144 98 94,000 

09/11/2012 10:30 CST 219,000 98 96 58,100 219,000 150 98 89,000 

10/10/2012 12:00 CDT 239,000 134 90 86,500 239,000 177 93 115,000 

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
208 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/14/2012 10:30 CST 332,000 124 74 111,000 332,000 172 81 154,000 

12/11/2012 10:45 CST 209,000 56 96 31,500 209,000 97 95 55,000 

01/19/2013 10:30 CST 728,000 420 72 825,000 728,000 432 73 850,000 

02/05/2013 13:45 CST 828,000 265 63 592,000 828,000 305 65 683,000 

03/05/2013 10:30 CST 625,000 208 66 351,000 625,000 242 72 410,000 

04/09/2013 11:45 CDT 752,000 194 55 393,000 752,000 228 63 463,000 

04/30/2013 10:45 CDT 1,080,000 297 76 867,000 1,080,000 332 79 966,000 

05/14/2013 11:00 CDT E 1,300,000 130 60 457,000 1,180,000 156 67 499,000 

06/04/2013 09:30 CDT E 1,120,000 186 45 562,000 995,000 215 53 579,000 

07/09/2013 11:15 CDT 780,000 196 69 413,000 780,000 227 74 479,000 

08/13/2013 10:00 CDT 418,000 79 83 89,600 418,000 111 89 125,000 

09/11/2013 09:30 CDT 351,000 61 94 58,100 351,000 84 96 80,000 

10/02/2013 11:00 CDT 281,000 70 98 53,100 — — — — 

11/05/2013 11:15 CST 265,000 129 99 92,400 — — — — 

12/18/2013 13:00 CST 601,000 224 84 363,000 — — — — 

01/07/2014 12:00 CST 954,000 246 76 633,000 — — — — 

02/05/2014 10:30 CST 442,000 150 64 179,000 — — — — 

03/05/2014 12:00 CST 815,000 355 70 781,000 — — — — 

04/09/2014 10:30 CDT 692,000 381 89 712,000 — — — — 

04/22/2014 12:00 CDT 1,050,000 230 58 651,000 — — — — 

05/06/2014 10:30 CDT 774,000 209 77 437,000 — — — — 

06/10/2014 12:45 CDT 668,000 139 74 250,000 — — — — 

07/22/2014 09:45 CDT 734,000 311 88 616,000 — — — — 

08/06/2014 10:15 CDT 457,000 99 88 122,000 — — — — 

09/10/2014 10:15 CDT 379,000 82 94 84,200 — — — — 

10/08/2014 12:30 CDT 342,000 124 94 115,000 — — — — 

1

Original results were incorrectly attributed to 08/10/2009, likely mistakenly entered from the sample collected on 12/08/2009.

Table 4–5. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Mississippi River at 

Union Point, Louisiana (U.S. Geological Survey station 07295025).—Continued

[Discharge supplied by the U.S. Army Corps of Engineers. Before March 1991, sediment and flows were measured at Coochie (U.S. Geological Survey 

[USGS] station 310552091361200) and were considered hydrologically equivalent to flows at Union Point (USGS 07295025). During higher flows at Union 

Point (UPT), the Mississippi River is not well constrained by the riverbanks, and measurements made “from treeline to treeline” likely underestimate the flow; 

therefore, a linear regression model, UPT=[(TAR+ORO)*0.9813]+6182.4, was used to estimate flow whenever the combined flows from Tarbert Landing 

(TAR) and the Old River Outflow (ORO) were greater than 1,120,000 cubic feet per second. Discharges estimated by linear regression are assigned the “E” 

remark code to indicate higher uncertainty. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the USGS National Water 

Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) is equivalent to “percent fines” as 

used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected because of a lack of metadata. CDT, 

central daylight time; CST, central standard time]
Appendix 4 209

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/17/1989 12:30 EDT 54,400 63 89 9,220 54,400 129 98 18,900 

11/20/1989 12:30 EST 32,700 28 93 2,500 32,700 55 99 4,560 

12/12/1989 13:45 EST 39,600 58 88 6,150 39,600 95 98 10,100 

01/23/1990 11:45 EST 54,900 277 99 41,100 54,900 332 100 49,200 

02/15/1990 11:30 EST 118,000 478 83 152,000 118,000 493 89 157,000 

03/20/1990 13:00 EST 113,000 342 78 104,000 113,000 355 83 108,000 

04/11/1990 11:30 EDT 119,000 325 79 104,000 119,000 368 87 118,000 

05/29/1990 16:00 EDT 133,000 497 76 178,000 133,000 441 79 158,000 

06/18/1990 12:15 EDT 137,000 291 71 108,000 137,000 303 74 112,000 

07/03/1990 12:20 EDT 104,000 342 89 95,900 104,000 354 90 99,400 

09/11/1990 12:00 EDT 49,100 56 98 7,430 — — — — 

09/24/1990 12:15 EDT 26,800 80 98 5,810 26,800 97 100 7,050 

10/15/1990 12:00 EDT 23,600 28 96 1,810 23,600 57 99 3,630 

01/22/1991 12:30 EST 160,000 — — — 160,000 355 62 153,000 

02/13/1991 12:00 EST 97,300 157 80 41,200 97,300 186 88 48,900 

03/19/1991 12:00 EST 118,000 130 68 41,200 118,000 163 79 51,900 

04/16/1991 15:45 EDT 132,000 199 65 71,100 132,000 238 44 84,800 

05/21/1991 16:30 EDT 139,000 273 78 103,000 139,000 312 81 117,000 

06/13/1991 09:45 EDT 120,000 171 85 55,500 120,000 195 87 63,200 

07/31/1991 12:15 EDT 29,100 61 74 4,780 — — — — 

08/21/1991 11:30 EDT 25,000 — — — — — — — 

09/17/1991 11:30 EDT 25,100 — — — 25,100 52 99 3,520 

10/24/1991 09:30 EDT 26,300 32 81 2,300 26,000 83 94 5,820 

11/25/1991 13:45 EST 45,400 121 96 14,800 45,000 172 98 20,900 

12/18/1991 09:15 EST 109,000 373 87 110,000 109,000 454 91 134,000 

01/28/1992 12:15 EST 79,000 195 95 41,500 79,000 260 98 55,600 

03/10/1992 12:00 EST 83,800 — — — 84,000 289 92 65,600 

04/01/1992 12:00 EST 100,000 75 97 20,300 — — — — 

05/06/1992 10:00 EDT 75,600 348 95 71,100 76,000 378 97 77,600 

05/20/1992 10:30 EDT 36,500 200 80 19,700 36,000 246 87 23,900 

07/08/1992 09:45 EDT 52,000 99 95 13,900 52,000 147 98 20,600 

07/30/1992 10:40 EDT 65,000 228 99 40,000 65,000 266 100 46,600 

09/09/1992 09:00 EDT 30,800 — — — 31,000 159 95 13,300 
210 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/01/1992 12:00 EDT 51,300 — — — — — — — 

10/29/1992 08:30 EST 39,100 38 76 4,010 39,000 135 97 14,200 

11/25/1992 09:00 EST 71,800 162 99 31,400 72,000 217 100 42,000 

12/23/1992 08:00 EST 91,600 436 96 108,000 92,000 491 98 122,000 

02/09/1993 08:30 EST 113,000 158 62 48,100 113,000 210 74 64,000 

02/25/1993 08:45 EST 81,200 196 93 43,100 81,000 271 97 59,000 

03/24/1993 08:00 EST 125,000 296 71 99,700 125,000 297 78 100,000 

04/29/1993 09:25 EDT 161,000 260 55 113,000 161,000 272 66 118,000 

05/19/1993 08:45 EDT 162,000 328 66 143,000 162,000 360 74 157,000 

07/01/1993 09:00 EDT 94,700 — — — 95,000 325 97 83,000 

07/21/1993 10:30 EDT 93,300 247 95 62,300 93,000 313 98 79,000 

08/19/1993 08:45 EDT 115,000 179 82 55,500 115,000 248 89 77,000 

09/29/1993 09:10 EDT 68,700 140 97 26,000 69,000 208 100 39,000 

10/28/1993 07:30 EDT 70,100 224 99 42,300 70,100 239 99 45,000 

11/23/1993 08:00 EST 74,200 181 98 36,300 74,200 225 99 45,000 

01/19/1994 08:00 EST 67,800 89 93 16,200 67,800 108 96 20,000 

03/03/1994 09:00 EST 131,000 280 65 99,100 131,000 300 72 106,000 

03/23/1994 08:00 EST 144,000 206 56 80,200 144,000 230 69 89,000 

04/05/1994 09:00 EDT 133,000 161 67 57,900 — — — — 

04/20/1994 08:15 EDT 140,000 166 55 62,900 140,000 261 79 99,000 

05/05/1994 09:00 EDT 162,000 195 65 85,100 162,000 288 79 126,000 

05/12/1994 12:00 EDT 169,000 214 74 97,500 — — — — 

06/02/1994 08:30 EDT 121,000 216 85 70,400 121,000 279 90 91,000 

06/23/1994 10:30 EDT 57,500 152 99 23,700 — — — — 

07/06/1994 11:30 EDT 56,500 111 97 16,900 — — — — 

07/19/1994 09:15 EDT 62,800 147 100 24,900 62,800 232 100 39,000 

08/26/1994 08:15 EDT 41,000 39 96 4,330 41,000 170 100 19,000 

09/07/1994 10:15 EDT 45,800 56 92 6,930 — — — — 

09/22/1994 08:30 EDT 39,300 11 100 1,150 39,300 56 99 5,900 

10/14/1994 12:00 EDT 35,700 44 98 4,270 36,000 81 99 7,850 

10/26/1994 09:30 EDT 55,000 77 98 11,400 55,000 93 99 13,900 

11/03/1994 09:00 EST 48,000 42 95 5,430 48,000 66 99 8,540 

11/17/1994 09:00 EST 45,000 97 99 11,800 42,000 133 100 15,100 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 211

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/07/1994 09:00 EST 79,100 88 100 18,800 79,000 127 100 27,100 

12/21/1994 09:15 EST 101,000 257 97 70,100 101,000 341 99 92,900 

01/04/1995 09:30 EST 76,200 86 95 17,600 76,000 95 97 19,500 

02/16/1995 16:00 EST 81,400 99 89 21,700 81,000 141 93 30,800 

03/14/1995 09:15 EST 105,000 201 86 56,900 105,000 251 90 71,200 

03/31/1995 08:45 EST 105,000 106 83 30,200 — — — — 

04/07/1995 14:30 EDT 86,400 96 85 22,300 86,000 136 94 31,600 

04/28/1995 12:45 EDT 119,000 418 79 134,000 119,000 404 88 130,000 

05/03/1995 08:50 EDT 121,000 308 73 101,000 121,000 350 80 114,000 

05/25/1995 13:30 EDT 143,000 318 67 123,000 143,000 345 76 133,000 

06/08/1995 13:00 EDT 191,000 386 62 199,000 191,000 393 72 203,000 

06/22/1995 09:45 EDT 206,000 306 61 170,000 206,000 324 72 180,000 

07/06/1995 15:00 EDT 164,000 211 64 93,400 164,000 284 78 126,000 

07/20/1995 08:10 EDT 108,000 113 96 32,900 108,000 182 99 53,100 

08/03/1995 12:00 EDT 66,700 83 98 14,900 67,000 155 100 28,000 

08/17/1995 13:10 EDT 83,400 132 94 29,600 83,000 204 99 45,700 

08/30/1995 13:30 EDT 65,500 77 99 13,600 66,000 154 100 27,500 

09/14/1995 14:30 EDT 49,300 24 99 3,240 49,000 100 99 13,200 

09/27/1995 14:30 EDT 34,900 — — — 35,000 234 100 22,100 

10/12/1995 14:40 EDT 31,400 — — — 31,400 145 99 12,300 

10/25/1995 16:00 EDT 32,100 — — — 32,100 89 99 7,740 

11/08/1995 13:00 EST 39,800 18 99 1,930 39,800 96 99 10,400 

12/01/1995 09:15 EST 58,200 49 99 7,730 58,200 107 99 16,800 

12/04/1995 12:30 EST 54,800 39 97 5,740 54,800 123 99 18,200 

01/04/1996 12:30 EST 61,100 58 96 9,520 61,100 127 100 21,000 

01/17/1996 12:30 EST 42,700 60 98 6,860 44,888 114 100 13,200 

01/30/1996 12:00 EST 88,400 279 94 66,600 88,400 338 97 80,800 

02/21/1996 10:00 EST 97,800 144 84 38,100 97,800 323 95 85,400 

02/29/1996 13:45 EST 72,200 118 89 23,000 72,200 234 99 45,700 

03/14/1996 08:40 EST 103,000 155 87 43,100 103,000 330 100 91,600 

03/26/1996 08:00 EST 98,200 99 96 26,200 98,200 214 100 56,600 

04/10/1996 12:00 EDT 123,000 219 67 72,700 123,000 269 91 89,200 

04/23/1996 11:00 EDT 88,700 — — — 88,700 245 100 58,600 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
212 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

05/09/1996 08:25 EDT 128,000 185 97 63,800 128,000 257 99 88,700 

05/22/1996 16:05 EDT 149,000 172 95 69,300 149,000 211 99 85,000 

06/05/1996 08:30 EDT 175,000 108 100 51,000 175,000 142 100 67,300 

07/02/1996 14:50 EDT 143,000 105 99 40,500 143,000 160 100 61,900 

07/18/1996 11:05 EDT 73,900 — — — 73,900 255 100 50,800 

07/31/1996 09:30 EDT 59,300 96 100 15,400 59,300 238 100 38,100 

08/14/1996 13:00 EDT 70,300 139 100 26,400 70,300 214 100 40,600 

08/28/1996 13:00 EDT 50,000 — — — 50,000 231 100 31,200 

09/10/1996 13:20 EDT 53,000 80 94 11,500 53,000 189 100 27,100 

09/24/1996 11:00 EDT 45,000 36 96 4,390 45,000 151 100 18,400 

10/09/1996 09:10 EDT 77,600 133 97 28,000 78,000 292 100 61,500 

10/22/1996 11:30 EDT 40,200 — — — 40,000 96 100 10,400 

11/07/1996 10:00 EST 76,000 94 97 19,300 76,000 156 100 32,000 

11/21/1996 10:00 EST 109,000 227 87 66,900 109,000 316 93 93,000 

12/03/1996 09:30 EST 128,000 546 93 189,000 128,000 636 95 220,000 

12/23/1996 12:00 EST 154,000 140 89 58,400 154,000 208 94 86,000 

01/22/1997 09:30 EST 109,000 97 98 28,600 109,000 183 100 54,000 

02/06/1997 09:00 EST 142,000 180 96 68,900 142,000 269 100 103,000 

02/19/1997 12:00 EST 164,000 313 66 139,000 164,000 375 77 166,000 

03/05/1997 12:00 EST 168,000 260 95 118,000 168,000 363 97 165,000 

03/18/1997 14:30 EST 215,000 222 85 129,000 215,000 314 89 182,000 

04/02/1997 10:30 EST 232,000 277 59 174,000 232,000 347 75 217,000 

04/17/1997 10:40 EDT 208,000 155 78 86,800 208,000 218 85 123,000 

05/01/1997 09:15 EDT 172,000 166 89 77,000 172,000 271 93 126,000 

05/15/1997 13:30 EDT 156,000 107 95 45,000 156,000 209 98 88,000 

05/28/1997 10:45 EDT 125,000 195 92 65,600 125,000 287 96 97,000 

06/26/1997 09:35 EDT 149,000 156 79 62,700 149,000 313 92 126,000 

07/17/1997 09:36 EDT 90,400 197 95 48,000 90,000 377 99 92,000 

07/30/1997 12:00 EDT 59,400 35 87 5,650 59,000 308 100 119,000 

08/14/1997 12:00 EDT 49,300 28 81 3,700 49,000 301 100 40,000 

09/03/1997 10:22 EDT 55,800 38 92 5,720 56,000 160 100 24,000 

09/17/1997 10:30 EDT 51,900 41 92 5,670 52,000 168 100 24,000 

09/30/1997 09:00 EDT 50,700 28 98 3,840 51,000 186 100 26,000 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 213

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/15/1997 10:25 EDT 47,000 23 97 2,870 47,000 232 100 29,400 

10/30/1997 12:00 EST 48,300 39 99 5,120 48,000 250 100 32,300 

11/14/1997 09:00 EST 58,800 31 98 4,910 59,000 120 99 19,000 

11/25/1997 14:40 EST 31,500 22 91 1,830 32,000 157 99 13,500 

12/09/1997 10:30 EST 34,700 20 96 1,840 34,700 177 100 16,700 

12/22/1997 15:30 EST 53,900 46 92 6,730 54,000 180 100 26,200 

01/07/1998 09:33 EST 88,100 — — — — — — — 

01/23/1998 12:00 EST 170,000 — — — 170,000 1,060 87 487,000 

02/05/1998 10:15 EST 132,000 — — — 132,000 793 92 282,000 

02/19/1998 10:27 EST 133,000 282 73 101,000 133,000 353 83 127,000 

03/03/1998 16:30 EST 153,000 292 56 120,000 153,000 351 73 145,000 

04/29/1998 11:00 EDT 150,000 133 95 53,800 150,000 230 99 93,100 

05/07/1998 13:15 EDT 169,000 187 61 85,500 169,000 264 76 120,000 

05/22/1998 10:00 EDT 178,000 88 97 42,300 178,000 190 99 91,200 

06/04/1998 14:35 EDT 130,000 135 76 47,500 130,000 238 91 83,500 

07/17/1998 12:00 EDT 116,000 226 91 70,700 — — — — 

07/28/1998 10:00 EDT 92,600 255 97 63,600 93,000 364 99 91,400 

08/27/1998 13:10 EDT 65,200 86 99 15,100 65,000 240 100 42,000 

09/09/1998 13:50 EDT — — — — — — — — 

09/23/1998 14:00 EDT 43,200 136 100 15,800 — — — — 

10/08/1998 12:00 EDT 55,100 39 99 5,740 55,000 105 100 15,600 

11/12/1998 13:40 EST 56,500 — — — 56,500 164 100 25,000 

12/10/1998 11:00 EST 58,500 78 95 12,300 58,500 207 100 32,700 

01/13/1999 14:30 EST 82,600 — — — 82,600 1,260 100 280,000 

03/25/1999 13:30 EST 162,000 191 68 83,500 162,000 303 80 133,000 

04/14/1999 13:00 EDT 123,000 122 98 40,500 123,000 179 100 59,000 

05/05/1999 10:15 EDT 132,000 226 88 80,400 132,000 299 92 107,000 

05/18/1999 11:45 EDT 154,000 192 79 79,700 154,000 300 87 125,000 

07/26/1999 11:30 EDT 80,900 — — — 80,900 315 100 69,000 

08/31/1999 11:15 EDT 43,100 48 99 5,630 43,100 160 100 19,000 

09/08/1999 11:30 EDT 30,900 37 100 3,110 30,900 112 99 9,400 

10/26/1999 10:00 EDT 33,100 51 84 4,510 33,100 134 98 12,000 

11/17/1999 09:30 EST 26,600 — — — 26,600 150 95 10,700 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
214 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/27/1999 11:00 EST 58,700 — — — 58,700 330 100 52,300 

02/02/2000 09:30 EST 39,100 23 100 2,380 39,100 131 99 13,900 

04/06/2000 08:45 EDT 111,000 242 95 72,400 110,000 316 97 93,900 

05/17/2000 10:00 EDT 67,300 82 97 14,900 67,300 139 100 25,200 

06/13/2000 08:00 EDT 68,900 91 97 16,900 68,900 164 99 30,500 

07/11/2000 14:30 EDT 112,000 210 93 63,400 112,000 264 94 79,700 

07/26/2000 12:00 EDT 62,200 44 100 7,330 62,200 87 99 14,500 

08/29/2000 10:30 EDT 43,300 40 95 4,680 43,300 103 99 12,100 

09/28/2000 10:00 EDT 41,000 13 100 1,440 41,000 55 99 6,130 

10/31/2000 10:30 EST 44,700 23 100 2,820 44,700 50 99 6,010 

11/15/2000 14:00 EST 41,000 45 98 4,960 41,000 87 99 9,580 

12/20/2000 10:15 EST 37,400 41 100 4,090 37,400 103 100 10,400 

01/31/2001 09:45 EST 85,000 160 97 36,700 85,000 227 99 52,000 

02/21/2001 11:00 EST 127,000 369 83 126,000 127,000 444 87 152,000 

03/22/2001 12:00 EST 162,000 397 64 174,000 162,000 499 73 218,000 

03/29/2001 09:15 EST 159,000 280 77 120,000 159,000 332 81 143,000 

04/04/2001 09:30 EDT 154,000 246 66 102,000 154,000 323 75 134,000 

04/18/2001 09:30 EDT 123,000 172 78 57,200 123,000 260 88 86,400 

04/30/2001 10:00 EDT 120,000 196 86 63,400 120,000 261 91 84,700 

05/23/2001 10:00 EDT 81,600 74 100 16,300 81,600 242 99 53,300 

05/31/2001 09:30 EDT 106,000 252 93 72,200 106,000 391 97 112,000 

06/21/2001 13:30 EDT 132,000 267 93 95,200 132,000 489 96 174,000 

06/27/2001 09:30 EDT 113,000 183 93 55,700 113,000 276 96 84,100 

07/12/2001 12:00 EDT 71,800 179 100 34,600 71,800 289 100 56,100 

08/01/2001 09:30 EDT 50,700 148 100 20,300 50,700 239 100 32,700 

08/29/2001 09:00 EDT 38,500 29 98 3,010 38,500 63 99 6,600 

09/27/2001 09:00 EDT 42,200 18 96 2,040 42,200 62 99 7,110 

11/01/2001 10:00 EST 62,400 57 100 9,650 62,400 89 100 15,100 

12/20/2001 09:30 EST 140,000 265 79 100,000 140,000 319 82 120,000 

01/28/2002 10:00 EST 81,400 87 100 19,000 81,400 117 100 25,600 

02/22/2002 10:00 EST 124,000 129 85 43,300 124,000 178 89 59,500 

02/26/2002 09:30 EST 121,000 117 87 38,300 121,000 164 91 53,500 

03/14/2002 09:00 EST 85,400 53 92 12,200 85,400 123 98 28,500 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 215

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/28/2002 09:00 EST 153,000 438 93 181,000 153,000 561 95 232,000 

04/16/2002 09:30 EDT 195,000 264 76 139,000 195,000 565 89 297,000 

04/29/2002 10:00 EDT 154,000 167 89 69,500 154,000 211 91 87,900 

05/09/2002 11:00 EDT 154,000 162 86 67,200 154,000 209 89 86,700 

05/23/2002 09:30 EDT 183,000 305 79 151,000 183,000 368 83 182,000 

06/13/2002 09:30 EDT 179,000 103 73 49,500 179,000 139 80 67,000 

06/25/2002 13:00 EDT 120,000 166 96 53,800 120,000 211 98 68,000 

07/11/2002 09:30 EDT 59,000 66 95 10,500 59,000 181 99 28,800 

08/07/2002 11:00 EDT 48,200 40 100 5,240 48,200 132 99 17,000 

08/21/2002 09:30 EDT 36,600 40 100 3,930 36,600 100 99 9,890 

09/23/2002 11:00 EDT 32,300 30 100 2,630 32,800 72 99 6,390 

09/30/2002 11:00 EDT 54,900 29 100 4,340 54,900 69 99 10,200 

11/19/2002 11:00 CST 72,800 72 99 14,100 72,800 126 100 24,800 

12/23/2002 10:30 CST 83,900 82 95 18,600 83,900 141 92 31,900 

01/16/2003 10:15 CST 116,000 111 89 34,800 116,000 152 93 47,800 

02/03/2003 10:45 CST 58,300 50 96 7,890 58,300 126 99 19,900 

02/26/2003 10:30 CST 144,000 349 89 136,000 144,000 409 90 159,000 

03/19/2003 10:30 CST 171,000 143 73 65,900 171,000 184 79 84,800 

03/27/2003 08:30 CST 142,000 119 77 45,500 142,000 153 82 58,800 

04/10/2003 10:30 CST 105,000 96 92 27,300 105,000 146 95 41,300 

04/22/2003 10:30 CST 87,100 104 96 24,400 87,100 160 99 37,600 

06/03/2003 12:30 CST 184,000 165 77 81,900 184,000 205 82 102,000 

06/25/2003 15:00 CST 138,000 147 89 54,700 138,000 196 93 73,000 

07/02/2003 12:00 CST 127,000 132 93 45,300 127,000 183 95 62,800 

07/16/2003 10:15 CDT 68,500 70 100 13,000 68,500 124 100 22,900 

07/29/2003 11:30 CDT 80,500 108 97 23,400 80,500 178 100 38,700 

08/13/2003 11:00 CDT 71,000 62 99 11,900 71,000 143 100 27,400 

08/28/2003 14:15 CDT 45,700 21 97 2,530 45,700 65 100 8,060 

09/17/2003 10:30 CDT 88,300 140 98 33,400 88,300 229 100 54,700 

09/25/2003 10:30 CDT 57,000 43 100 6,580 57,000 79 100 12,100 

10/16/2003 14:00 CDT 57,700 29 99 4,580 57,700 72 100 11,200 

11/19/2003 11:00 CST 69,100 58 100 10,800 69,100 118 100 22,100 

12/17/2003 14:45 CST 89,600 114 96 27,500 89,300 174 99 41,900 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
216 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

01/15/2004 10:30 CST 106,000 98 91 28,100 106,000 163 95 46,800 

02/13/2004 10:30 CST 122,000 214 93 70,400 122,000 260 94 85,500 

02/27/2004 13:45 CST 147,000 152 79 60,300 147,000 200 84 79,300 

03/08/2004 10:30 CST 119,000 113 90 36,200 119,000 158 93 50,800 

03/29/2004 10:30 CST 141,000 132 83 50,200 141,000 166 86 63,200 

04/08/2004 14:00 CST 112,000 93 94 28,100 112,000 135 97 40,800 

04/28/2004 11:30 CST 99,100 109 96 29,200 99,100 159 98 42,500 

05/13/2004 11:45 CST 138,000 122 91 45,500 138,000 159 94 59,300 

05/20/2004 08:15 CST 138,000 158 92 58,900 138,000 188 94 70,200 

06/15/2004 10:30 CST 152,000 246 93 101,000 152,000 317 95 130,000 

06/29/2004 10:30 CST 159,000 165 86 70,900 159,000 210 89 90,200 

07/15/2004 12:00 CST 140,000 121 90 45,600 2182,000 154 93 275,900 

07/29/2004 12:00 CST 80,400 122 98 26,400 80,400 181 99 39,400 

08/12/2004 09:45 CST 73,200 74 98 14,500 73,200 164 100 32,400 

09/09/2004 10:00 CST 57,400 57 100 8,760 57,400 145 100 22,500 

10/21/2004 09:15 CDT 52,100 55 99 7,760 52,100 134 99 18,800 

11/22/2004 10:30 CST 97,400 106 93 28,000 97,400 158 96 41,600 

12/15/2004 14:00 CST 163,000 234 77 103,000 163,000 291 81 128,000 

12/28/2004 09:00 CST 178,000 151 62 72,300 178,000 191 71 91,700 

01/18/2005 10:30 CST 168,000 248 83 112,000 168,000 292 85 132,000 

02/09/2005 13:30 CST 209,000 129 61 73,000 209,000 171 71 96,300 

03/03/2005 14:15 CST 151,000 148 86 60,400 151,000 186 89 75,900 

03/29/2005 11:15 CST 91,700 67 95 16,600 91,700 127 99 31,300 

05/05/2005 13:45 CST 93,400 80 98 20,300 93,400 153 100 38,500 

05/19/2005 10:30 CST 74,200 73 99 14,700 74,200 152 100 30,500 

06/02/2005 10:45 CDT 77,000 141 100 29,300 77,000 319 100 66,300 

06/30/2005 10:00 CDT 68,500 169 100 31,200 68,500 254 100 46,900 

07/14/2005 10:30 CDT 52,800 56 100 7,940 52,800 179 100 25,500 

07/26/2005 12:45 CDT 53,500 16 100 2,230 53,500 143 100 20,600 

08/11/2005 11:00 CDT 34,400 26 100 2,400 34,400 71 100 6,640 

09/19/2005 11:30 CDT 48,300 26 100 3,440 48,300 71 99 9,290 

10/13/2005 10:30 CDT 35,300 21 99 2,040 35,300 59 99 5,640 

11/29/2005 10:35 CST 62,000 43 100 7,200 62,000 146 100 24,400 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 217

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/08/2006 13:50 CST 108,000 272 96 79,300 108,000 334 97 97,300 

02/22/2006 11:05 CST 67,100 87 100 15,700 67,100 148 100 26,900 

03/08/2006 11:30 CST 45,800 63 100 7,780 — — — — 

05/03/2006 11:35 CST 89,100 137 99 32,900 89,100 257 100 61,700 

05/10/2006 13:05 CDT 90,500 111 99 27,100 — — — — 

06/01/2006 10:35 CDT 65,100 73 99 12,800 65,100 240 100 42,300 

06/06/2006 11:35 CDT 65,200 67 100 11,900 65,200 207 100 36,400 

06/12/2006 11:05 CDT 47,600 38 98 4,880 47,600 120 100 15,400 

06/28/2006 10:05 CDT 33,900 35 96 3,200 33,900 150 99 13,800 

07/13/2006 13:35 CDT 46,100 30 98 3,780 40,900 69 99 7,590 

07/19/2006 10:35 CDT 46,900 27 97 3,420 46,900 92 99 11,600 

08/23/2006 10:35 CDT 28,800 — — — 28,800 175 100 13,600 

09/20/2006 10:05 CDT 32,900 38 100 3,340 32,900 262 100 23,200 

10/31/2006 10:30 CDT 65,200 — — — 65,200 159 96 28,000 

11/29/2006 10:30 CDT 81,800 105 98 23,100 81,800 172 100 38,000 

01/26/2007 10:30 CDT 174,000 348 82 164,000 174,000 392 84 184,000 

02/07/2007 13:00 CDT 154,000 132 78 54,900 154,000 169 83 70,300 

03/21/2007 12:30 CST 115,000 157 95 48,900 115,000 213 96 66,100 

04/04/2007 12:15 CST 118,000 159 94 50,700 118,000 214 96 68,300 

04/18/2007 12:00 CST 123,000 140 95 46,500 123,000 216 98 71,600 

05/02/2007 11:30 CST 126,000 131 94 44,500 126,000 287 98 97,600 

06/13/2007 10:00 CST 72,400 103 100 20,100 72,400 185 100 36,200 

06/26/2007 12:00 CST 77,300 128 100 26,600 — — — — 

07/18/2007 10:30 CST 105,000 220 98 62,400 105,000 272 99 77,000 

07/24/2007 12:30 CST 97,500 167 98 44,000 97,500 229 99 60,300 

07/31/2007 10:30 CST 81,600 108 99 23,900 81,600 179 100 39,500 

08/22/2007 12:00 CDT 44,700 38 100 4,520 44,700 110 100 13,300 

09/20/2007 11:00 CDT 60,400 71 100 11,600 36,040 141 100 32,300 

09/27/2007 11:00 CDT 53,000 49 100 6,940 53,000 118 100 16,900 

10/18/2007 10:45 CDT 38,600 21 100 2,160 38,600 68 100 7,060 

12/18/2007 13:30 CST 51,900 51 100 7,080 51,900 158 100 22,200 

02/07/2008 10:45 CST 84,500 92 97 20,900 84,500 135 99 30,900 

02/25/2008 11:00 CST 161,000 319 87 139,000 161,000 352 88 153,000 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
218 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/06/2008 09:00 CST 158,000 183 81 77,900 158,000 225 85 95,800 

03/19/2008 10:30 CST 174,000 284 88 134,000 174,000 320 90 150,000 

03/27/2008 14:30 CDT 187,000 250 85 126,000 187,000 284 86 143,000 

04/03/2008 11:15 CDT 204,000 253 79 139,000 204,000 287 81 158,000 

04/17/2008 10:45 CDT 228,000 200 75 123,000 228,000 235 79 145,000 

04/28/2008 11:00 CDT 239,000 196 78 126,000 239,000 234 81 151,000 

06/05/2008 13:30 CDT 173,000 85 90 39,800 173,000 145 95 67,700 

06/25/2008 12:00 CDT 156,000 217 94 91,400 156,000 258 95 109,000 

07/17/2008 14:00 CDT 149,000 150 94 60,400 149,000 199 96 79,900 

07/31/2008 11:00 CDT 86,600 109 100 25,500 86,600 194 100 45,400 

08/14/2008 13:00 CDT 99,200 278 99 74,500 99,200 352 99 94,300 

09/25/2008 11:00 CDT 105,000 133 99 37,600 105,000 168 100 47,600 

11/20/2008 11:00 CST 41,700 43 99 4,870 41,700 88 100 9,860 

02/12/2009 12:30 CST 90,200 120 99 29,200 90,200 204 100 49,700 

02/25/2009 10:30 CST 124,000 212 95 70,900 124,000 274 96 91,800 

03/10/2009 09:30 CST 107,000 111 96 32,200 107,000 185 99 53,500 

04/03/2009 10:30 CDT 149,000 188 85 75,500 149,000 238 88 95,600 

05/12/2009 10:30 CDT 173,000 274 89 128,000 173,000 314 91 147,000 

06/10/2009 13:00 CDT 200,000 121 78 65,100 200,000 158 84 85,500 

06/24/2009 10:30 CDT 146,000 120 92 47,300 146,000 156 95 61,300 

07/13/2009 12:00 CDT 98,700 143 100 38,000 98,700 214 100 56,900 

07/27/2009 13:00 CDT 79,400 82 98 17,600 79,400 152 99 32,600 

08/27/2009 09:30 CDT 60,200 50 98 8,200 60,200 88 99 14,300 

09/23/2009 12:00 CST 74,500 67 100 13,500 74,500 110 100 22,100 

11/11/2009 10:00 CST 182,000 268 76 132,000 182,000 295 79 145,000 

12/22/2009 13:00 CST 156,000 165 82 69,300 156,000 235 88 99,000 

01/28/2010 12:00 CST 127,000 164 92 56,100 127,000 260 96 89,000 

02/18/2010 12:30 CST 197,000 206 69 109,000 197,000 303 79 161,000 

03/04/2010 13:00 CST 160,000 104 75 44,900 160,000 214 89 92,000 

05/25/2010 13:30 CST 170,000 145 86 66,700 170,000 182 89 83,000 

06/02/2010 13:30 CST 170,000 111 83 50,800 170,000 208 92 95,000 

08/05/2010 12:40 CST 105,000 177 100 50,200 105,000 336 97 95,000 

08/24/2010 14:00 CDT 82,800 126 99 28,200 — — — — 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 219

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

09/13/2010 14:30 CST 73,000 84 100 16,500 73,000 243 100 48,000 

09/30/2010 13:30 CST 71,000 72 99 13,800 71,000 264 99 51,000 

10/06/2010 13:30 CST 66,000 106 100 18,800 66,000 241 100 43,000 

02/28/2011 14:00 CST 65,000 — — — 65,000 630 100 111,000 

03/10/2011 14:00 CST 155,000 549 90 230,000 155,000 626 92 262,000 

04/26/2011 15:20 CST 155,000 115 90 47,900 155,000 208 96 87,000 

05/05/2011 14:00 CST 189,000 170 78 86,700 189,000 238 85 122,000 

05/19/2011 12:40 CST 244,000 250 73 164,000 244,000 308 79 203,000 

05/24/2011 14:00 CST 284,000 243 73 186,000 284,000 295 78 226,000 

06/01/2011 10:00 CST 309,000 177 68 147,000 309,000 230 76 192,000 

06/15/2011 12:20 CST 211,000 98 71 55,900 211,000 152 82 86,000 

06/29/2011 10:15 CST 150,000 139 93 56,100 150,000 196 96 79,000 

07/13/2011 10:30 CST 132,000 119 96 42,400 132,000 206 99 73,000 

08/25/2011 11:15 CDT 71,200 62 99 12,000 71,200 150 100 29,000 

10/04/2011 11:30 CDT 55,200 44 97 6,560 55,200 229 100 34,000 

11/02/2011 12:30 CDT 50,100 31 100 4,140 50,100 110 100 1149,000 

01/25/2012 13:30 CST 106,000 51 98 14,600 106,000 104 100 1298,000 

02/08/2012 11:40 CST 156,000 218 87 92,000 156,000 268 90 113,000 

03/19/2012 10:30 CST 139,000 150 94 56,400 139,000 194 97 72,700 

04/18/2012 10:05 CDT 113,000 80 96 24,500 113,000 132 99 40,400 

05/03/2012 12:30 CDT 62,900 50 100 8,470 62,900 119 100 20,200 

06/06/2012 12:30 CDT 51,800 29 100 4,010 47,200 92 100 11,700 

06/14/2012 10:30 CDT 47,700 33 100 4,260 47,700 94 100 12,200 

07/24/2012 13:00 CDT 43,800 26 98 3,050 43,800 91 100 10,800 

08/21/2012 13:00 CDT 53,800 32 99 4,680 53,800 83 100 12,100 

09/27/2012 10:20 CDT 32,000 40 98 3,480 32,000 132 100 11,400 

10/11/2012 12:00 CDT 39,600 29 100 3,120 39,600 113 100 12,200 

03/04/2013 13:40 CST 103,000 132 98 36,700 103,000 184 100 51,400 

03/21/2013 13:40 CDT 103,000 109 97 30,200 103,000 189 99 52,700 

04/04/2013 12:00 CDT 143,000 153 87 59,200 143,000 238 93 92,000 

04/17/2013 13:00 CDT 134,000 119 97 43,100 134,000 182 99 66,000 

05/15/2013 12:20 CDT 176,000 122 80 58,000 176,000 166 86 79,100 

07/02/2013 13:30 CDT 145,000 129 93 50,700 145,000 230 97 90,100 

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
220 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/11/2013 13:00 CDT 117,000 113 98 35,600 117,000 197 100 62,400 

08/21/2013 10:10 CDT 84,300 107 98 24,300 84,300 209 100 47,700 

09/25/2013 13:30 CDT 57,300 30 100 4,570 57,300 92 100 14,300 

11/19/2013 13:00 CST 58,700 53 100 8,430 — — — — 

01/08/2014 12:00 CST 135,000 186 95 68,000 — — — — 

03/12/2014 13:15 CDT 131,000 159 91 56,300 — — — — 

03/27/2014 13:00 CDT 95,500 72 99 18,500 — — — — 

04/09/2014 12:40 CDT 108,000 153 98 44,500 — — — — 

04/30/2014 13:00 CDT 147,000 126 88 50,100 — — — — 

06/26/2014 12:00 CDT 116,000 253 99 79,200 — — — — 

07/29/2014 14:00 CDT 92,700 125 98 31,200 — — — — 

08/14/2014 14:20 CDT 62,800 49 99 8,340 — — — — 

08/20/2014 10:00 CDT 49,200 37 100 4,930 — — — — 

09/10/2014 12:40 CDT 58,800 73 100 11,600 — — — — 

10/21/2014 12:10 CDT 87,900 151 98 35,900 — — — — 

11/24/2014 16:00 CST 57,500 63 99 9,810 — — — — 

01/06/2015 14:30 CST 95,300 157 99 40,300 — — — — 

02/10/2015 13:20 CST 59,100 48 100 7,710 — — — — 

1

Due to data-entry errors, the original result for suspended-sediment discharge on 07/30/1997 should have been reported as 49,000 short tons per day, the 

original result for suspended-sediment discharge on 11/02/2011 should have been reported as 14,900 short tons per day, and the original result for suspendedsediment discharge on 01/25/2012 should have been reported as 29,800 short tons per day.

2

Original discharge result on 07/15/2004 was in error and should have been 140,000 cubic feet per second, which would have resulted in a sediment discharge 

result of 58,200 short tons per day.

Table 4–6. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Wax Lake Outlet at 

Calumet, Louisiana (U.S. Geological Survey station 07381590).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 221

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

10/18/1989 09:45 EDT 115,000 76 85 23,600 115,000 128 96 39,700 

11/21/1989 09:15 EST 79,000 45 90 9,640 79,000 72 99 15,400 

12/13/1989 09:30 EST 97,500 56 80 14,800 98,000 81 96 21,500 

01/24/1990 09:00 EST 153,000 444 92 183,000 153,000 474 94 196,000 

02/16/1990 09:45 EST 253,000 — — — 253,000 541 71 369,000 

03/21/1990 08:30 EST 234,000 443 61 280,000 234,000 449 70 284,000 

04/12/1990 09:00 EDT 247,000 — — — 247,000 386 79 257,000 

05/30/1990 09:45 EDT 269,000 473 67 344,000 269,000 482 76 350,000 

06/19/1990 08:00 EDT 269,000 310 66 225,000 — — — — 

07/04/1990 09:15 EDT 227,000 324 87 199,000 227,000 371 91 227,000 

07/26/1990 11:00 EDT 142,000 130 93 49,600 — — — — 

08/23/1990 09:00 EDT 98,900 95 99 25,400 99,000 111 99 29,600 

09/25/1990 09:30 EDT 85,900 107 96 24,700 85,900 105 99 24,400 

10/16/1990 09:45 EDT 98,000 77 98 20,400 98,000 92 100 24,340 

01/23/1991 09:15 EST 364,000 — — — — — — — 

02/14/1991 08:30 EST 221,000 221 60 132,000 221,000 214 63 127,700 

03/20/1991 08:45 EST 237,000 196 47 125,000 237,000 331 74 211,800 

04/17/1991 08:45 EDT 244,000 305 59 201,000 244,000 336 67 221,400 

05/22/1991 08:45 EDT 294,000 327 66 260,000 294,000 362 68 287,400 

06/12/1991 11:00 EDT 244,000 230 64 152,000 244,000 268 72 176,600 

08/01/1991 09:30 EDT 69,300 60 80 11,100 — — — — 

08/22/1991 08:30 EDT 76,000 94 90 19,200 — — — — 

09/18/1991 08:15 EDT 61,700 24 89 3,980 61,700 57 99 9,496 

10/23/1991 11:15 EDT 53,600 51 91 7,410 54,000 106 98 15,400 

11/26/1991 09:30 EST 136,000 196 95 72,100 136,000 251 97 92,300 

12/17/1991 11:45 EST 216,000 470 78 274,000 216,000 537 83 313,000 

01/29/1992 08:40 EST 174,000 — — — 174,000 252 87 118,000 

03/11/1992 07:45 EST 183,000 — — — 183,000 290 87 143,000 

04/02/1992 09:45 EST 224,000 296 60 179,000 224,000 324 68 196,000 

05/05/1992 11:45 EDT 166,000 190 96 85,000 166,000 240 97 108,000 

05/19/1992 11:45 EDT 98,900 96 97 25,500 98,900 149 99 40,000 

07/07/1992 12:00 EDT 133,000 174 96 62,400 133,000 189 99 68,000 

07/29/1992 13:00 EDT 140,000 250 96 94,300 140,000 227 99 86,000 
222 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

09/09/1992 14:30 EDT 88,800 54 99 13,000 88,800 80 98 19,000 

09/30/1992 10:30 EDT 112,000 — — — 112,000 121 95 37,000 

10/28/1992 10:30 EST 98,600 48 86 12,600 99,000 102 96 27,000 

11/24/1992 13:30 EST 134,000 203 88 73,600 134,000 287 93 104,000 

12/22/1992 10:45 EST 194,000 302 99 158,000 194,000 348 99 182,000 

02/08/1993 12:45 EST 234,000 — — — 234,000 241 61 152,000 

02/24/1993 12:30 EST 174,000 163 99 76,400 174,000 205 100 96,000 

03/23/1993 11:00 EST 261,000 388 52 274,000 261,000 347 68 245,000 

04/28/1993 11:45 EDT 308,000 348 51 289,000 308,000 334 59 278,000 

05/18/1993 12:15 EDT 294,000 — — — 294,000 393 76 312,000 

06/30/1993 12:15 EDT 201,000 162 89 88,100 201,000 246 90 133,000 

07/20/1993 11:00 EDT 180,000 272 90 132,000 180,000 333 95 162,000 

08/18/1993 11:00 EDT 236,000 191 85 122,000 236,000 242 85 154,000 

09/28/1993 10:55 EDT 147,000 150 98 59,700 147,000 207 97 82,000 

10/27/1993 11:15 EDT 147,000 147 93 58,400 — — — — 

11/22/1993 12:25 EST 148,000 187 93 74,500 148,000 234 94 93,000 

12/15/1993 11:00 EST 215,000 — — — 215,000 350 75 203,000 

01/18/1994 12:30 EST 145,000 89 79 34,700 145,000 110 85 43,000 

03/02/1994 11:15 EST 256,000 321 46 222,000 256,000 305 56 211,000 

03/22/1994 11:50 EST 288,000 340 41 264,000 288,000 330 51 257,000 

04/05/1994 13:30 EDT 266,000 — — — — — — — 

04/19/1994 11:00 EDT 267,000 158 51 114,000 267,000 252 73 182,000 

05/04/1994 11:40 EDT 303,000 239 54 195,000 303,000 341 71 279,000 

05/12/1994 12:00 EDT 319,000 — — — — — — — 

06/01/1994 14:00 EDT 232,000 — — — 232,000 237 89 149,000 

06/23/1994 14:30 EDT 119,000 164 97 52,700 — — — — 

07/06/1994 15:30 EDT 114,000 203 97 62,300 — — — — 

07/18/1994 13:30 EDT 114,000 159 98 48,900 — — — — 

08/25/1994 11:30 EDT 78,200 29 90 6,170 78,000 154 100 33,000 

09/07/1994 15:30 EDT 82,100 52 77 11,400 — — — — 

09/21/1994 14:00 EDT 80,500 16 87 3,460 80,000 63 99 14,000 

10/13/1994 14:00 EDT 77,800 44 100 9,270 78,000 99 99 20,900 

10/25/1994 13:00 EDT 100,000 60 97 16,200 100,000 120 98 32,500 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 223

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/02/1994 12:00 EST 76,000 42 97 8,600 76,000 68 99 13,900 

11/16/1994 11:30 EST 92,600 118 99 29,500 93,000 159 100 40,000 

12/06/1994 13:00 EST 128,000 90 99 30,900 128,000 153 100 53,000 

12/20/1994 11:30 EST 156,000 159 100 66,900 156,000 209 100 88,000 

01/03/1995 14:30 EST 138,000 50 99 18,500 138,000 74 99 27,800 

01/19/1995 11:00 EST 129,000 121 87 42,200 129,000 197 94 68,500 

01/30/1995 14:30 EST 190,000 102 99 52,200 — — — — 

02/01/1995 12:00 EST 190,000 302 77 155,000 190,000 333 84 171,000 

02/16/1995 10:00 EST 144,000 124 88 48,300 144,000 156 93 60,800 

03/30/1995 11:30 EST — 173 77 — — — — — 

04/07/1995 10:30 EDT 136,000 129 93 47,200 136,000 165 97 60,600 

04/28/1995 09:10 EDT 170,000 322 91 148,000 170,000 374 94 172,000 

05/02/1995 10:45 EDT 182,000 269 85 132,000 182,000 301 90 148,000 

05/25/1995 09:00 EDT 208,000 250 81 140,000 208,000 281 89 158,000 

06/08/1995 09:30 EDT 264,000 333 60 237,000 264,000 360 70 257,000 

06/21/1995 10:50 EDT 325,000 389 46 341,000 325,000 379 61 333,000 

07/06/1995 10:00 EDT 229,000 170 72 105,000 229,000 209 80 129,000 

07/19/1995 10:40 EDT 161,000 — — — 161,000 127 99 55,100 

08/02/1995 12:45 EDT 108,000 — — — 108,000 179 100 52,100 

08/17/1995 08:30 EDT 114,000 147 97 45,300 114,000 218 99 67,100 

09/27/1995 10:00 EDT 87,800 — — — 88,000 234 99 55,600 

10/12/1995 12:00 EDT 82,200 — — — 82,200 138 99 30,600 

10/25/1995 10:30 EDT 95,000 29 100 7,540 95,000 104 99 26,700 

11/08/1995 12:00 EST 90,900 44 96 10,800 — — — — 

11/30/1995 12:00 EST 93,600 56 96 14,200 93,600 119 100 30,100 

12/05/1995 10:30 EST 94,900 52 94 13,300 94,900 131 99 33,700 

01/03/1996 12:00 EST 112,000 76 96 22,900 112,000 117 100 35,400 

01/17/1996 12:00 EST 100,000 67 100 18,000 100,000 109 100 29,500 

01/31/1996 09:00 EST 153,000 305 88 126,000 153,000 354 92 146,000 

02/21/1996 14:00 EST 154,000 129 94 53,500 154,000 280 99 116,000 

02/29/1996 09:30 EST 142,000 125 95 48,100 142,000 251 98 96,100 

03/12/1996 10:50 EST 110,000 — — — — — — — 

03/25/1996 10:00 EST 139,000 133 98 49,700 139,000 218 98 81,900 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
224 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

04/10/1996 12:15 EDT 172,000 — — — — — — — 

04/22/1996 12:10 EDT 122,000 — — — 122,000 277 100 91,100 

05/09/1996 13:00 EDT 177,000 140 100 67,000 177,000 171 100 81,700 

05/22/1996 08:50 EDT 208,000 129 98 72,200 208,000 171 97 96,200 

06/05/1996 11:20 EDT 235,000 99 97 62,600 235,000 122 98 77,200 

06/18/1996 07:50 EDT 264,000 282 50 201,000 — — — — 

07/02/1996 11:00 EDT 199,000 146 81 78,200 199,000 272 93 1416,000 

07/18/1996 08:40 EDT 116,000 91 99 28,400 116,000 229 100 71,800 

07/30/1996 12:30 EDT 92,700 115 93 28,800 92,700 270 99 67,700 

08/14/1996 09:10 EDT 107,000 131 93 38,000 107,000 242 99 70,000 

08/29/1996 09:00 EDT 90,500 50 90 12,300 90,500 186 100 45,500 

09/10/1996 10:45 EDT 71,900 63 93 12,100 71,900 176 100 34,100 

09/23/1996 12:30 EDT 68,700 38 100 7,020 68,700 105 100 19,500 

10/09/1996 12:30 EDT 108,000 145 98 42,200 108,000 350 100 102,000 

10/22/1996 14:30 EDT 47,000 40 96 5,050 47,000 112 100 14,000 

11/06/1996 09:55 EST 112,000 63 98 19,100 112,000 146 100 44,000 

11/21/1996 16:00 EST 136,000 183 99 67,100 136,000 247 100 91,000 

12/03/1996 13:00 EST 179,000 531 92 257,000 179,000 638 94 309,000 

12/23/1996 14:00 EST 205,000 112 97 62,200 205,000 204 100 113,000 

02/19/1997 15:30 EST 224,000 363 54 219,000 224,000 401 69 242,000 

03/05/1997 12:00 EST 228,000 269 92 166,000 228,000 350 95 216,000 

04/02/1997 13:30 EST 381,000 236 54 243,000 381,000 336 69 346,000 

04/17/1997 13:30 EDT 315,000 114 87 96,500 315,000 175 93 149,000 

04/30/1997 13:30 EDT 240,000 306 54 198,000 240,000 388 67 251,000 

05/15/1997 10:20 EDT 226,000 80 98 48,600 226,000 180 99 110,000 

05/28/1997 15:45 EDT 180,000 186 93 90,600 180,000 282 97 137,000 

07/29/1997 11:00 EDT 93,100 30 80 7,610 93,000 247 99 62,000 

08/14/1997 14:00 EDT 81,600 24 89 5,240 82,000 241 100 53,000 

09/03/1997 14:00 EDT 84,200 25 95 5,650 84,000 155 100 35,000 

09/17/1997 14:00 EDT 56,900 24 81 3,680 57,000 243 100 37,000 

09/29/1997 10:15 EDT 65,200 22 98 3,850 65,200 194 100 34,000 

10/14/1997 15:05 EDT 36,700 18 98 1,750 37,000 178 100 17,800 

10/29/1997 11:45 EST 70,400 25 99 4,770 70,000 186 100 35,000 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 225

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/13/1997 11:40 EST 74,200 19 86 3,760 74,000 136 100 27,000 

11/25/1997 10:00 EST 84,000 30 100 6,820 84,000 138 99 31,000 

12/10/1997 09:20 EST 91,200 23 100 5,620 91,000 187 100 46,000 

12/22/1997 11:30 EST 94,600 55 100 14,100 95,000 185 100 48,000 

01/06/1998 11:00 EST 111,000 — — — 111,000 979 99 290,000 

01/23/1998 14:15 EST 232,000 — — — 232,000 1,229 88 770,000 

02/05/1998 14:30 EST 190,000 — — — 190,000 732 91 376,000 

02/18/1998 11:05 EST 183,000 259 74 128,000 183,000 322 83 159,000 

03/03/1998 09:45 EST 210,000 260 63 148,000 210,000 317 73 180,000 

03/31/1998 14:00 EST 269,000 — — — 269,000 405 74 294,000 

04/28/1998 13:00 EDT 222,000 234 58 140,000 222,000 321 75 192,000 

05/07/1998 09:30 EDT 237,000 222 52 142,000 237,000 303 70 194,000 

05/21/1998 14:00 EDT 255,000 84 88 57,700 255,000 171 96 118,000 

06/04/1998 11:00 EDT 196,000 135 87 71,500 196,000 242 93 128,000 

07/01/1998 09:30 EDT 173,000 367 91 171,000 173,000 515 95 241,000 

07/16/1998 12:00 EDT 179,000 260 90 126,000 179,000 372 93 180,000 

07/28/1998 14:30 EDT 145,000 269 95 105,000 145,000 463 98 181,000 

08/12/1998 13:00 EDT 116,000 75 100 23,500 116,000 230 100 71,900 

08/27/1998 09:37 EDT 93,000 83 97 20,900 93,000 223 100 56,000 

09/09/1998 09:35 EDT 83,500 142 100 31,900 84,000 966 100 219,000 

09/23/1998 10:00 EDT 68,900 112 99 20,900 69,000 674 100 126,000 

10/08/1998 13:00 EDT 66,900 40 98 7,280 67,000 132 100 24,000 

11/11/1998 14:00 EST 90,700 112 96 27,500 91,000 222 100 54,000 

12/10/1998 14:00 EST 79,000 68 94 14,500 79,000 168 100 36,000 

01/13/1999 12:00 EST 118,000 — — — 118,000 1,114 100 355,000 

03/25/1999 15:30 EST 213,000 249 52 143,000 213,000 395 70 227,000 

04/13/1999 14:00 EDT 171,000 142 93 65,700 171,000 233 98 108,000 

05/04/1999 12:00 EDT 164,000 232 92 103,000 164,000 303 95 134,000 

05/19/1999 10:00 EDT 224,000 202 78 122,000 224,000 268 85 162,000 

07/27/1999 11:00 EDT 112,000 152 100 45,900 112,000 384 100 116,000 

09/01/1999 11:00 EDT 58,000 44 96 6,880 58,000 153 100 24,000 

09/09/1999 09:30 EDT 68,000 50 99 9,140 68,000 247 100 45,000 

10/26/1999 16:00 EDT 38,800 48 92 4,980 38,800 150 99 15,700 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
226 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/23/1999 10:00 EST 64,900 36 91 6,280 65,000 91 98 16,000 

12/27/1999 14:45 EST 87,800 38 99 9,100 87,800 344 100 81,400 

02/02/2000 14:00 EST 24,800 31 100 2,040 24,800 194 99 13,000 

04/06/2000 14:25 EDT 147,000 222 95 88,000 147,000 302 97 120,000 

05/17/2000 13:00 EDT 87,300 81 98 19,200 87,300 129 100 30,400 

06/12/2000 11:00 EDT 106,000 112 92 32,100 106,000 174 98 49,800 

07/10/2000 16:30 EDT 158,000 201 91 85,600 158,000 255 94 109,000 

07/26/2000 15:00 EDT 102,000 50 100 13,800 102,000 87 100 23,900 

08/29/2000 14:00 EDT 53,600 40 98 5,760 53,600 112 99 16,200 

09/28/2000 13:00 EDT 56,000 17 100 2,590 56,000 54 99 8,150 

10/31/2000 13:00 EST 62,300 22 100 3,710 62,300 65 100 10,900 

11/16/2000 08:00 EST 81,100 34 94 7,380 81,100 85 100 18,600 

12/20/2000 12:30 EST 22,900 40 100 2,470 22,900 142 100 8,790 

01/31/2001 12:00 EST 117,000 170 96 53,500 117,000 257 98 81,200 

02/21/2001 13:30 EST 158,000 368 84 157,000 158,000 482 88 206,000 

03/23/2001 10:00 EST 216,000 311 77 182,000 216,000 391 83 228,000 

03/29/2001 12:30 EST 210,000 310 67 176,000 210,000 418 76 237,000 

04/04/2001 12:30 EDT 212,000 254 65 145,000 212,000 350 75 200,000 

04/18/2001 12:00 EDT 175,000 172 92 81,200 175,000 236 95 112,000 

04/30/2001 12:00 EDT 150,000 195 85 79,100 150,000 267 90 108,000 

05/23/2001 13:00 EDT 106,000 104 100 29,700 106,000 164 100 46,800 

05/31/2001 11:00 EDT 127,000 258 94 88,500 127,000 416 98 143,000 

06/20/2001 13:00 EDT 165,000 254 92 113,000 165,000 343 94 153,000 

06/27/2001 11:30 EDT 153,000 184 93 76,100 153,000 264 96 109,000 

07/12/2001 09:30 EDT 102,000 184 100 50,700 102,000 280 100 77,000 

08/01/2001 12:30 EDT 74,300 37 100 7,400 74,300 115 100 23,200 

08/29/2001 11:00 EDT 40,300 28 100 2,990 40,300 66 100 7,200 

09/27/2001 12:00 EDT 56,500 23 100 3,520 56,500 62 99 9,440 

11/01/2001 13:00 EST 68,600 61 100 11,300 68,600 90 100 16,700 

12/20/2001 13:30 EST 187,000 278 78 140,000 187,000 331 82 167,000 

01/28/2002 12:30 EST 114,000 104 97 32,000 114,000 136 98 42,000 

02/22/2002 12:00 EST 171,000 120 83 55,400 171,000 177 90 81,800 

02/26/2002 12:00 EST 166,000 114 81 50,900 166,000 166 88 74,500 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 227

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

03/14/2002 12:00 EST 113,000 59 95 18,000 113,000 136 99 41,300 

03/28/2002 12:00 EST 187,000 477 88 241,000 187,000 610 90 308,000 

04/16/2002 13:00 EDT 272,000 392 53 288,000 272,000 513 64 377,000 

04/29/2002 12:00 EDT 217,000 174 79 102,000 217,000 245 85 144,000 

05/09/2002 14:00 EDT 210,000 250 64 142,000 210,000 321 72 182,000 

05/23/2002 12:00 EDT 229,000 208 73 129,000 229,000 279 80 173,000 

06/13/2002 12:00 EDT 239,000 143 54 92,100 239,000 176 63 113,000 

06/25/2002 10:00 EDT 163,000 185 95 81,200 163,000 254 97 111,800 

07/11/2002 12:00 EDT 88,000 91 98 21,600 88,000 204 100 48,470 

08/07/2002 16:00 EDT 76,500 41 97 8,450 76,500 181 99 37,390 

08/21/2002 12:00 EDT 51,500 31 98 4,360 51,500 180 99 25,000 

09/23/2002 14:00 EDT 38,700 25 100 2,600 38,700 86 99 9,030 

09/30/2002 12:00 EDT 76,200 30 99 6,180 76,200 66 100 13,500 

11/21/2002 09:45 CST 108,000 89 97 25,900 108,000 134 99 39,100 

12/23/2002 13:00 CST 117,000 104 95 33,000 117,300 171 98 54,200 

01/16/2003 12:30 CST 157,000 124 78 52,600 157,000 186 86 79,000 

02/03/2003 13:45 CST 59,100 57 98 9,070 59,100 136 99 21,700 

02/26/2003 13:15 CST 160,000 361 87 156,000 160,000 419 89 181,000 

03/21/2003 08:30 CST 217,000 195 46 114,000 217,000 248 63 145,000 

03/27/2003 11:00 CST 172,000 135 72 62,800 172,000 189 81 87,800 

04/10/2003 12:30 CST 135,000 101 94 36,900 135,000 164 98 59,800 

04/22/2003 12:45 CST 105,000 111 99 31,400 105,000 166 99 47,000 

06/04/2003 15:15 CST 266,000 209 63 150,000 266,000 256 70 184,000 

06/26/2003 08:30 CST 167,000 150 88 67,400 167,000 189 91 85,000 

07/03/2003 09:00 CST 161,000 118 95 51,200 161,000 188 98 81,600 

07/16/2003 13:30 CDT 97,300 74 100 19,400 97,300 140 100 36,700 

07/29/2003 14:00 CDT 102,000 124 99 34,200 102,000 190 100 52,400 

08/14/2003 08:30 CDT 84,000 63 100 14,400 84,000 151 100 34,200 

08/27/2003 15:00 CDT 57,800 32 99 4,980 57,800 83 100 12,900 

09/17/2003 12:45 CDT 116,000 110 99 34,600 116,000 258 100 80,600 

09/25/2003 13:00 CDT 71,900 44 100 8,530 71,900 80 100 15,600 

10/15/2003 15:45 CDT 62,400 40 99 6,660 62,400 87 100 14,600 

11/19/2003 15:00 CST 88,200 61 99 14,500 88,200 131 100 31,100 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
228 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

12/16/2003 13:30 CST 130,000 117 94 40,900 130,000 179 97 62,900 

01/15/2004 13:00 CST 134,000 113 84 41,000 134,000 200 91 72,500 

02/13/2004 13:00 CST 154,000 234 92 97,300 154,000 283 93 118,000 

02/26/2004 14:45 CST 207,000 220 67 123,000 207,000 266 72 149,000 

03/08/2004 12:30 CST 160,000 139 83 60,200 160,000 183 88 79,200 

03/29/2004 12:45 CST 176,000 150 67 71,300 176,000 196 75 93,100 

04/07/2004 15:45 CST 147,000 91 87 36,000 147,000 146 93 57,800 

04/27/2004 16:00 CST 120,000 91 96 29,600 120,000 153 99 49,400 

05/13/2004 09:30 CDT 174,000 140 80 65,800 174,000 213 87 100,000 

05/19/2004 14:45 CDT 173,000 142 89 66,100 173,000 181 92 84,400 

06/15/2004 13:30 CDT 184,000 271 89 134,000 184,000 353 92 175,000 

06/29/2004 13:00 CDT 196,000 192 77 101,000 196,000 252 83 134,000 

07/15/2004 14:00 CDT 182,000 138 81 67,800 182,000 182 86 89,400 

07/28/2004 14:30 CDT 116,000 115 99 36,100 116,000 177 100 55,400 

08/11/2004 14:00 CDT 94,100 81 99 20,600 94,100 175 100 44,400 

09/08/2004 14:30 CDT 87,300 107 90 25,300 87,300 173 94 40,700 

10/20/2004 14:00 CDT 85,000 62 100 14,100 85,000 142 100 32,600 

11/22/2004 13:30 CST 127,000 115 93 39,500 127,000 202 98 69,300 

12/14/2004 14:45 CST 222,000 326 63 195,000 222,000 391 69 234,000 

12/27/2004 16:00 CST 244,000 270 40 178,000 244,000 316 49 208,000 

01/18/2005 14:15 CST 218,000 315 61 185,000 218,000 384 69 226,000 

02/09/2005 15:30 CST 299,000 298 29 240,000 299,000 340 38 275,000 

03/02/2005 17:00 CST 195,000 170 75 89,700 195,000 227 81 119,000 

03/29/2005 14:00 CST 125,000 70 95 23,500 125,000 155 99 52,300 

05/04/2005 15:30 CDT 121,000 104 94 34,000 121,000 203 98 66,300 

05/19/2005 13:00 CDT 98,500 83 85 22,000 98,500 156 92 41,600 

06/02/2005 13:30 CDT 107,000 147 100 42,600 107,000 283 100 81,800 

06/30/2005 12:30 CDT 91,600 163 100 40,200 91,600 286 100 70,700 

07/14/2005 13:00 CDT 78,500 61 100 13,000 78,500 162 100 34,400 

07/26/2005 16:00 CDT 78,300 — — — — — — — 

08/11/2005 13:00 CDT 60,600 24 100 3,980 60,600 66 100 10,900 

09/19/2005 13:30 CDT 67,000 20 99 3,520 67,000 76 99 13,700 

10/13/2005 12:30 CDT 44,500 21 100 2,570 44,500 57 99 6,790 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 229

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

11/29/2005 13:00 CST 68,600 40 100 7,450 68,600 159 100 29,500 

02/07/2006 15:15 CST 142,000 309 93 118,000 142,000 371 94 142,000 

02/22/2006 13:30 CST 78,800 89 100 18,900 78,800 147 100 31,300 

03/08/2006 14:30 CST 34,000 63 100 5,760 34,000 222 99 20,400 

05/03/2006 14:00 CDT 110,000 133 99 39,500 110,000 305 100 90,600 

05/10/2006 15:35 CDT 107,000 125 98 36,200 107,000 242 100 69,800 

06/01/2006 15:05 CDT 92,100 105 97 26,100 92,100 311 99 77,400 

06/06/2006 14:35 CDT 78,300 63 100 13,200 78,300 197 100 41,700 

06/12/2006 15:05 CDT 76,900 33 100 6,880 76,900 119 99 24,600 

06/28/2006 14:05 CDT 49,200 37 100 4,860 49,200 137 100 18,200 

07/13/2006 12:05 CDT 39,300 23 100 2,460 39,300 70 100 7,390 

07/19/2006 15:05 CDT 76,600 29 97 5,890 76,600 127 100 26,200 

08/23/2006 14:35 CDT 29,900 27 99 2,200 29,900 151 100 12,200 

09/20/2006 15:05 CDT 24,100 50 100 3,230 24,100 245 100 15,900 

10/31/2006 13:30 CST 95,300 96 99 24,800 95,300 158 99 40,600 

11/29/2006 13:30 CST 99,100 103 99 27,600 99,100 184 100 49,300 

01/26/2007 13:30 CST 232,000 388 69 243,000 232,000 436 73 273,000 

02/08/2007 09:30 CST 211,000 156 61 88,900 211,000 197 70 112,000 

03/21/2007 17:15 CST 144,000 170 93 66,000 144,000 236 95 91,600 

04/04/2007 16:30 CST 147,000 165 93 65,400 147,000 232 96 92,200 

04/18/2007 15:30 CST 151,000 145 89 59,300 151,000 200 92 81,300 

05/02/2007 16:00 CST 152,000 144 90 59,200 152,000 273 95 112,000 

06/13/2007 13:30 CDT 94,200 110 100 28,100 — — — — 

06/26/2007 07:45 CST 70,700 137 100 26,100 70,700 248 100 47,300 

07/18/2007 13:30 CST 133,000 218 98 78,400 133,000 309 99 111,000 

07/24/2007 09:00 CST 128,000 185 98 63,900 128,000 261 99 90,300 

07/31/2007 13:30 CST 108,000 120 99 34,900 108,000 196 100 57,100 

08/22/2007 13:00 CST 64,900 47 100 8,180 64,900 120 100 21,100 

09/20/2007 13:30 CST 87,500 86 100 20,200 87,500 151 100 35,600 

09/27/2007 13:30 CST 73,200 55 99 10,800 73,200 126 100 24,900 

10/18/2007 13:15 CDT 58,800 24 100 3,830 58,800 75 100 12,000 

12/18/2007 10:15 CST 73,900 66 100 13,100 73,900 156 100 31,100 

02/07/2008 14:30 CST 106,000 97 96 27,700 106,000 157 98 44,800 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
230 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

02/25/2008 13:30 CST 194,000 346 81 181,000 194,000 389 83 204,000 

03/05/2008 16:15 CST 190,000 235 69 121,000 190,000 284 74 146,000 

03/19/2008 14:00 CST 218,000 366 68 215,000 218,000 415 72 244,000 

03/27/2008 12:30 CDT 252,000 322 65 219,000 252,000 362 69 246,000 

04/03/2008 13:45 CDT 279,000 360 57 271,000 279,000 404 62 305,000 

04/17/2008 14:00 CDT 332,000 293 59 263,000 332,000 319 62 286,000 

04/28/2008 15:00 CDT 345,000 317 50 295,000 345,000 345 55 321,000 

06/05/2008 10:45 CDT 217,000 100 74 58,500 217,000 156 84 91,300 

06/24/2008 11:15 CDT 185,000 250 92 125,000 185,000 297 93 149,000 

07/17/2008 11:00 CDT 182,000 159 87 78,200 182,000 223 91 110,000 

07/31/2008 13:00 CDT 114,000 107 99 33,000 114,000 207 100 63,700 

08/14/2008 11:00 CDT 122,000 277 100 91,100 122,000 365 100 120,000 

09/25/2008 13:30 CDT 125,000 43 100 14,500 125,000 77 99 26,000 

11/20/2008 13:00 CST 67,300 55 99 10,100 67,300 99 100 18,000 

02/12/2009 12:30 CST 116,000 117 98 36,600 116,000 210 100 65,800 

02/25/2009 14:00 CST 154,000 218 94 90,600 154,000 294 96 122,000 

03/10/2009 12:00 CST 135,000 111 92 40,300 135,000 190 96 69,200 

04/03/2009 13:15 CST 177,000 175 82 83,600 177,000 238 87 114,000 

05/13/2009 08:20 CST 212,000 295 80 169,000 212,000 378 84 216,000 

06/11/2009 10:00 CST 268,000 148 61 107,000 268,000 191 70 138,000 

06/24/2009 13:00 CST 188,000 114 88 57,600 188,000 167 92 84,800 

07/13/2009 09:00 CST 117,000 148 97 46,600 117,000 234 99 73,900 

07/27/2009 10:00 CST 81,700 95 100 20,900 81,700 187 100 41,100 

08/27/2009 12:00 CST 76,800 68 99 14,100 76,800 96 99 20,000 

09/23/2009 10:00 CST 88,700 44 100 10,600 88,700 97 100 23,200 

11/11/2009 12:00 CST 230,000 312 66 194,000 230,000 343 70 213,000 

12/22/2009 10:30 CST 187,000 158 66 79,900 187,000 219 75 111,000 

01/28/2010 09:30 CST 159,000 165 87 70,600 159,000 338 94 145,000 

02/18/2010 10:00 CST 271,000 397 35 290,000 271,000 460 45 337,000 

03/04/2010 10:00 CST 192,000 124 58 64,000 192,000 194 74 101,000 

05/25/2010 10:30 CST 206,000 179 66 99,700 206,000 257 77 143,000 

06/02/2010 10:30 CST 220,000 174 50 103,000 220,000 254 67 151,000 

08/05/2010 10:15 CST 121,000 243 98 79,400 121,000 440 100 144,000 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
Appendix 4 231

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

08/24/2010 10:40 CST 95,400 143 100 36,900 — — — — 

09/13/2010 11:00 CST 85,000 88 100 20,100 85,000 215 99 49,000 

09/30/2010 10:20 CST 77,000 70 100 14,500 77,000 206 99 43,000 

10/06/2010 10:40 CST 84,000 133 100 30,200 84,000 247 100 56,000 

02/28/2011 11:20 CST 95,700 93 97 24,000 95,700 516 100 133,000 

03/10/2011 11:00 CST 174,000 607 86 285,000 174,000 689 88 342,000 

04/26/2011 11:40 CST 189,000 150 72 76,500 189,000 237 84 121,000 

05/05/2011 11:15 CST 224,000 199 66 121,000 224,000 271 76 164,000 

05/19/2011 09:40 CST 377,000 265 59 270,000 377,000 313 67 319,000 

05/24/2011 10:40 CST 459,000 244 56 303,000 459,000 289 63 358,000 

06/01/2011 12:01 CDT 478,000 247 35 319,000 478,000 299 47 386,000 

06/15/2011 10:45 CST 301,000 161 38 131,000 301,000 223 57 182,000 

06/29/2011 12:00 CST 188,000 119 95 60,400 188,000 180 98 91,000 

07/13/2011 12:30 CST 154,000 136 98 56,500 154,000 195 99 81,000 

08/24/2011 10:30 CDT 81,000 72 95 15,800 81,000 197 100 43,000 

10/04/2011 09:40 CDT 58,800 40 87 6,310 59,000 186 99 30,000 

11/02/2011 11:20 CDT 61,500 39 98 6,400 61,500 121 100 20,100 

01/25/2012 10:30 CST 121,000 61 96 19,800 120,000 133 100 43,000 

02/08/2012 14:00 CST 185,000 234 87 117,000 185,000 279 90 139,000 

03/19/2012 13:00 CST 159,000 168 94 71,900 159,000 218 97 93,500 

04/18/2012 12:00 CDT 150,000 101 98 40,700 150,000 155 100 62,800 

05/03/2012 10:00 CDT 83,200 44 100 9,850 83,200 112 100 25,300 

06/06/2012 10:00 CDT 48,700 25 100 3,310 48,700 101 100 13,200 

06/14/2012 12:00 CDT 67,100 28 97 4,990 67,100 82 99 14,800 

07/24/2012 10:30 CDT 30,400 33 99 2,680 30,400 98 100 8,050 

08/21/2012 09:45 CDT 61,900 26 98 4,290 61,900 84 100 14,000 

09/27/2012 10:20 CDT 44,500 45 89 5,450 44,500 122 96 14,600 

10/11/2012 13:20 CDT 45,400 51 99 6,260 45,400 118 99 14,500 

03/04/2013 10:30 CST 125,000 111 98 37,400 125,000 185 99 62,700 

03/21/2013 10:20 CDT 137,000 116 94 43,000 137,000 272 99 101,000 

04/04/2013 10:30 CDT 168,000 147 88 66,500 168,000 243 94 110,000 

04/17/2013 10:30 CDT 151,000 112 98 45,600 151,000 200 100 82,000 

05/15/2013 10:00 CDT 209,000 149 65 84,000 209,000 210 76 119,000 

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
232 Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015

Sample date

and time

(month/day/year 

hour:minutes)

Time 

datum

Corrected results Original results

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge 

(short tons 

per day)

Discharge, 

instantaneous 

(cubic feet 

per second)

Suspendedsediment 

concentration 

(milligrams 

per liter)

Suspended 

sediment 

smaller 

than 0.0625 

millimeter 

(percent)

Suspendedsediment 

discharge

(short tons

per day)

p00061 p80154 p70331 p80155 p00061 p80154 p70331 p80155

07/02/2013 10:30 CDT 180,000 141 84 68,600 180,000 282 93 137,000 

07/11/2013 10:20 CDT 139,000 114 97 42,800 139,000 263 100 99,000 

08/21/2013 11:10 CDT 102,000 146 99 40,100 102,000 272 100 75,000 

09/25/2013 10:00 CDT 67,900 38 100 6,940 67,000 93 99 17,000 

11/19/2013 10:40 CST 76,800 69 95 14,200 — — — — 

01/08/2014 11:10 CST 160,000 219 88 94,800 — — — — 

03/12/2014 11:00 CDT 152,000 170 86 69,800 — — — — 

03/27/2014 10:15 CDT 134,000 89 94 32,300 — — — — 

04/09/2014 10:30 CDT 138,000 252 99 93,800 — — — — 

04/30/2014 10:30 CDT 178,000 143 78 68,900 — — — — 

06/26/2014 11:30 CDT 138,000 284 99 106,000 — — — — 

07/29/2014 10:30 CDT 121,000 136 99 44,400 — — — — 

08/14/2014 11:00 CDT 79,400 58 97 12,400 — — — — 

08/20/2014 13:30 CDT 61,800 42 95 7,070 — — — — 

09/10/2014 10:10 CDT 75,000 90 99 18,200 — — — — 

10/21/2014 15:00 CDT 96,100 146 98 37,900 — — — — 

11/24/2014 11:00 CST 90,300 73 100 17,900 — — — — 

01/06/2015 11:40 CST 122,000 161 95 53,000 — — — — 

02/10/2015 10:40 CST 75,100 42 100 8,450 — — — — 

1

Due to a data-entry error, the original result for suspended-sediment discharge on 07/02/1996 should have been reported as 146,000 short tons per day.

Reference Cited

Norton, K.K., Olsen, L.D., Baumann, T.E., Simmons, L.B., Clark, A.P., Demcheck, D.K., and Johnson, M., 2019, Revised data 

and supporting information for seven sites located on the lower Mississippi and Atchafalaya Rivers sampled as part of a 

cooperative sediment program with the U.S. Army Corps of Engineers, October 1989 through February 2015: U.S. Geological 

Survey data release, https://doi.org/10.5066/F7K936GW.

Table 4–7. Corrected and original results for instantaneous discharge, suspended-sediment concentration, suspended-sediment 

percent smaller than 0.0625 millimeter, and suspended-sediment discharge for water samples collected from the Lower Atchafalaya 

River at Morgan City, Louisiana (U.S. Geological Survey station 07381600).—Continued

[Discharge data were supplied by the U.S. Geological Survey. The five-digit “pcode” below each constituent name uniquely identifies that constituent in the U.S. 

Geological Survey National Water Information System (NWIS) at http://waterdata.usgs.gov/nwis. Suspended sediment smaller than 0.0625 millimeter (p70331) 

is equivalent to “percent fines” as used in the body of the report. Results denoted as “—” were not available in the original dataset or could not be corrected 

because of a lack of metadata. EDT, eastern daylight time; EST, eastern standard time; CDT, central daylight time; CST, central standard time]
For more information about this publication, contact

Director, Lower Mississippi-Gulf Water Science Center

U.S. Geological Survey

640 Grassmere Park Drive

Nashville, TN 37211

For additional information visit

https://www.usgs.gov/centers/lmg-water

Publishing support provided by

Lafayette Publishing Service Center
Norton and others—Revisions to Suspended-Sediment and Discharge Data, Mississippi-Atchafalaya River Basin, 1989–2015—SIR 2018–5147

ISSN 2328-031X (print)

ISSN 2328-0328 (online)

https://doi.org/10.3133/sir20185147

I SBN 978- 1- 4113-4290- 3

9 7 8 1 41 1 3 4 2 9 0 3