Prepared in cooperation with the U.S. Environmental Protection Agency, Region 7

Surface-Water Quality and Suspended-Sediment Quantity 

and Quality within the Big River Basin, Southeastern 

Missouri, 2011–13

Scientific Investigations Report 2015–5171

U.S. Department of the Interior

U.S. Geological Survey
Front cover photographs: Left, baseflow sample collection by wading. Center, turbidity sensor 

equipped with a wiper to reduce sensor fouling. Right, stormflow event sampling from bridge.

Back cover photographs: Top, streamflow measuring during a large stormflow event at the 

upstream site. Center, turbidity sensor equipped with a wiper to reduce sensor fouling. 

Bottom, sediment sample processing at the Missouri Water Science Center Sediment Laboratory.

Background photograph: Large stormflow event during study period at the Byrnesville 

downstream site.
Surface-Water Quality and SuspendedSediment Quantity and Quality within the 

Big River Basin, Southeastern Missouri, 

2011–13

By Miya N. Barr

Prepared in cooperation with the U.S. Environmental Protection Agency, 

Region 7

Scientific Investigations Report 2015–5171

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia: 2016

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

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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:

Barr, M.N., 2016, Surface-water quality and suspended-sediment quantity and quality within the Big River Basin, 

southeastern Missouri, 2011–13: U.S. Geological Survey Scientific Investigations Report 2015–5171, 39 p., 

http://dx.doi.org/10.3133/sir20155171.

ISSN 2328-0328 (online)
iii

Contents

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

Introduction.....................................................................................................................................................2

Study Background ................................................................................................................................2

Purpose and Scope ..............................................................................................................................4

Description of Study Area ...................................................................................................................4

Methods...........................................................................................................................................................5

Field Methods........................................................................................................................................5

Laboratory Methods.............................................................................................................................7

Quality Assurance and Quality Control .............................................................................................7

Data Analysis and Reporting ..............................................................................................................9

Surface-Water Quality ................................................................................................................................13

Streamflow Conditions.......................................................................................................................13

Continuous Water Quality..................................................................................................................14

Suspended-Sediment Quantity..................................................................................................................19

Daily Suspended-Sediment Concentrations and Loads...............................................................22

Event-Based Suspended-Sediment Concentrations, Load, and Yields.....................................24

Suspended-Sediment Quality ....................................................................................................................25

Selected Trace-Element Concentrations in Suspended Sediments ..........................................25

Event-Based Loads and Yields of Selected Trace-Element Concentrations in 

Suspended Sediments..........................................................................................................31

Summary........................................................................................................................................................36

References Cited..........................................................................................................................................38

Figures

1. Map showing location of study sites and the Big River Basin .............................................3

2. Graphs showing turbidity duration curves for two study sites on the Big River,

Missouri, October 2011–September 2013 .................................................................................9

3. Graphs showing instantaneous turbidity in relation to discrete

suspended-sediment concentrations used to develop a regression model for the

computation of daily suspended-sediment concentrations and loads for two study

sites on the Big River, October 2011–September 2013 .........................................................11

4. Graphs showing daily mean streamflow in relation to discrete suspended-sediment

concentrations used to develop a regression model for the computation of

estimated daily suspended-sediment concentrations and loads for two study sites

on the Big River, Missouri, October 2011–September 2013.................................................12

5. Graph showing total monthly precipitation at two National Oceanic and

Atmospheric Administration climate stations near the Big River Basin, Missouri,

October 2011–September 2013.................................................................................................14

6. Graph showing daily mean streamflow computed during the study period at two

study sites on the Big River, Missouri, October 2011–September 2013.............................15

7. Graphs showing daily mean water temperature measured at two study sites on the

Big River, Missouri, October 2011–September 2013 .............................................................17
iv

8. Graphs showing daily mean turbidity measured at two study sites on the Big River,

Missouri, October 2011–September 2013 ...............................................................................18

9. Graphs showing continuous streamflow and discrete suspended-sediment

concentration samples collected at two study sites on the Big River, Missouri,

October 2011–September 2013.................................................................................................19

10. Graphs showing daily mean suspended-sediment concentrations computed at two

study sites on the Big River, Missouri, October 2011–September 2013.............................22

11. Graphs showing daily mean suspended-sediment loads computed at two study

sites on the Big River, Missouri, October 2011–September 2013 .......................................23

12. Graphs showing trace-element concentrations in two suspended-sediment size

fractions collected during stormflow events at two study sites on the Big River,

Missouri, October 2011–September 2013 ...............................................................................28

13. Graphs showing seasonal comparison of stormflow-event suspended-sediment

concentrations and mass-accumulation lead and zinc concentrations within

suspended sediments for two study sites on the Big River, Missouri, October

2011–September 2013 ................................................................................................................31

14. Graphs showing seasonal comparison of stormflow-event loads and yields of lead

and zinc in suspended sediments at two study sites on the Big River, Missouri,

October 2011–September 2013.................................................................................................35

Tables

1. Location information for study sites on the Big River, Missouri ...........................................5

2. Reporting limits of laboratory analyses ....................................................................................8

3. Summary statistics of model-calibration datasets for two study sites on the Big

River, October 2011–September 2013......................................................................................10

4. Streamflow statistics for two study sites on the Big River, Missouri, October

2011–September 2013 ................................................................................................................15

5. Water-quality statistics for two study sites on the Big River, Missouri, October

2011–September 2013 ................................................................................................................16

6. Concentrations and size distributions of suspended-sediment samples collected at

two study sites on the Big River, Missouri, October 2011–September 2013.....................20

7. Daily suspended-sediment concentration and load statistics at two study sites on

the Big River, Missouri, October 2011–September 2013 ......................................................24

8. Suspended-sediment concentrations, loads, and yields from sampled stormflow

events at two study sites on the Big River, Missouri, October 2011–September 2013 ...25

9. Selected trace-element concentrations for two particle size distributions of

suspended sediments collected during stormflow events at two study sites on the

Big River, Missouri, October 2011–September 2013 .............................................................26

10. Streamflow, suspended-sediment concentrations and particle-size distributions,

and selected total trace-element concentrations in suspended sediments collected

during stormflow events at two study sites on the Big River, Missouri, October

2011–September 2013 ................................................................................................................30

11. Selected trace element concentrations, loads, and yields in suspended sediments

from sampled stormflow events at two study sites on the Big River, Missouri,

October 2011–September 2013.................................................................................................32
v

Conversion Factors

[Inch/Pound 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

acre 4,047 square meter (m2)

square foot (ft2) 929.0 square centimeter (cm2)

square foot (ft2) 0.09290 square meter (m2)

square inch (in2) 6.452 square centimeter (cm2)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

cubic foot (ft3) 0.02832 cubic meter (m3) 

gallon (gal) 3.785 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

ounce, avoirdupois (oz) 28.35 gram (g) 

pound, avoirdupois (lb) 0.4536 kilogram (kg) 

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

ton per day (ton/d) 0.9072 metric ton per day

ton per day (ton/d) 0.9072 megagram per day (Mg/d)

short ton per day per square mile 0.3503 megagram per day per square 

kilometer [(Mg/d)/km2]

ton per year (ton/yr) 0.9072 megagram per year (Mg/yr)

ton per year (ton/yr) 0.9072 metric ton per year

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows: 

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

°C=(°F-32)/1.8

Datum

Vertical coordinate information is referenced to North American Vertical Datum of 1988 

(NAVD 88). 
vi

Supplemental Information

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).

Concentrations of chemical constituents in sediments are given in milligrams per kilogram 

(mg/kg).

Water year in U.S. Geological Survey reports is the 12-month period October 1 through 

September 30. The water year is designated by the calendar year in which it ends and 

which includes 9 of the 12 months. Thus, the year ending September 30, 2013 is called the 

“2013 water year.”

Abbreviations

ADAPS automated data processing system

ADCP acoustic Doppler current profiler

ASTM Association of Standards and Testing Materials

CWQM continuous water-quality monitor

DCP data collection platform

EPA U.S. Environmental Protection Agency

EWI equal-width increment

FISP Federal Interagency Sedimentation Project

FNU formazin nephelometric units

ICP-MS inductively-coupled plasma mass-spectrometry

MDNR Missouri Department of Natural Resources

MRL Minerals Research Laboratory

NIST National Institute of Standards and Technology

NOAA National Oceanographic and Atmospheric Association

NWIS National Water Information System

PEC probable effect concentration

PVC polyvinyl chloride

R2 coefficient of determination

R2

a adjusted coefficient of determination

SQG sediment quality guidelines

SSC suspended-sediment concentration

SSL suspended-sediment load

TEC threshold effect concentration

TET toxic effect threshold

USFWS U.S. Fish and Wildlife Service

USGS U.S. Geological Survey

YSI Yellow Springs, Incorporated
Surface-Water Quality and Suspended-Sediment Quantity 

and Quality within the Big River Basin, Southeastern 

Missouri, 2011–13

By Miya N. Barr

Abstract

Missouri was the leading producer of lead in the United 

States—as well as the world—for more than a century. One 

of the lead sources is known as the Old Lead Belt, located 

in southeast Missouri. The primary ore mineral in the region 

is galena, which can be found both in surface deposits and 

underground as deep as 200 feet. More than 8.5 million tons 

of lead were produced from the Old Lead Belt before operations ceased in 1972. Although active lead mining has ended, 

the effects of mining activities still remain in the form of large 

mine waste piles on the landscape typically near tributaries and the main stem of the Big River, which drains the Old 

Lead Belt. Six large mine waste piles encompassing more than 

2,800 acres, exist within the Big River Basin. These six mine 

waste piles have been an available source of trace element-rich 

suspended sediments transported by natural erosional processes downstream into the Big River. 

A study was performed by the U.S. Geological Survey 

in cooperation with U.S. Environmental Protection Agency, 

Region 7, to calculate and characterize suspended-sediment 

quantity and quality within the Big River basin after reclamation of the mine waste piles ended in 2012. Streamflow and 

suspended sediments were quantified and sampled at two 

locations along a 68-mile reach of the Big River between 

Bonne Terre and Byrnes Mill, Missouri. The results will 

help regulatory agencies, such as the U.S. Environmental Protection Agency and U.S. Fish and Wildlife Service, 

determine impaired reaches and ecosystems for remedial and 

restoration efforts. 

Continuous stream stage, water temperature, and turbidity, and discrete suspended-sediment concentration data 

were collected at the two sites between October 2011 and 

September 2013. Suspended-sediment samples were collected 

during various hydrologic conditions to develop a regression 

model between discrete suspended-sediment concentration and 

continuous turbidity. Suspended sediments collected during 

stormflow events were analyzed for concentrations of trace 

elements such as barium, cadmium, lead, and zinc within 

two sediment size fractions. Event loads and annual loads of 

suspended sediment and select trace elements in suspended 

sediments also were calculated. 

Suspended-sediment loads computed by the regression 

model increased downstream from about 201,000 tons at the 

upstream site to about 355,000 tons at the downstream site 

during the study period. Stormflow-event-based (hereinafter 

referred to as “event-based”) suspended-sediment loads ranged 

from 180 to 32,000 tons at the upstream sampling site and 

390 to 53,000 tons at the downstream site along the Big River. 

Although only seven stormflow events at the upstream site 

and six at the downstream site were sampled, the event-based 

suspended-sediment loads accounted for nearly 30 percent of 

the total suspended-sediment loads computed at both sites, 

indicating most of the suspended sediment transported through 

the Big River occurs during higher streamflows.

Sediment quality guidelines, known as the threshold 

effect concentration and the probable effect concentration, 

used to assess toxicity of trace-element concentrations in 

sediments were compared to the cadmium, lead, and zinc 

concentrations in suspended sediment samples collected 

during stormflow events. All concentrations of cadmium, 

lead, and zinc in event-based suspended sediment samples 

exceeded the threshold and probable effect concentrations. 

Lead and zinc concentrations in the sediment size fraction 

less than 0.063 millimeters also exceeded the toxic effect 

threshold, above which sediment is considered to be heavily 

polluted causing adverse effects on sediment-dwelling organisms. Concentrations of cadmium and zinc in event-based 

suspended sediment samples were notably higher in samples 

from the upstream site than samples from the downstream site, 

indicating the sources of sediments enriched in these trace 

elements decrease in the downstream area of the watershed. 

The reduction in concentration of cadmium and zinc could 

be from dissolution of the constituents during transport or 

possibly a decrease in downstream source material. The lead 

concentration exceedance of the probable effects concentration as well as the threshold effects concentration indicates 

that lead-rich suspended sediments in the fraction less than 

0.063 millimeters are readily available within the Big River 

Basin for transport. These sediments remain in the system 

from historical mining, and as the reclamation of mine waste 

piles in the upstream area of the watershed reduce additional 

sediment loadings, these fine sediments may be continually 
2 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

released as the river scours the streambed and erodes stream 

banks causing the lead-rich suspended sediment to remain in a 

state of equilibrium. 

Barium concentrations in suspended-sediments were 

nearly twice as high in stormflow event samples collected 

at the downstream site as compared to samples from the 

upstream site. The source of barium in the Big River could be 

from Mineral Fork and Mill Creek, which flow through the 

historical barite (barium sulfate, also known as tiff) mining 

district in Washington County, and discharge into the Big 

River between the two study sites. 

Total trace-element loads and yields in suspended sediments were computed from the sampled events for each year 

in the study. The total barium loads in suspended sediments 

were higher for sampled events collected at the downstream 

site than the upstream site during both study years. Cadmium 

and zinc loads in suspended sediments were lower at the 

downstream site than the upstream site, although the decrease 

in total load was not substantial during the study period. Lead 

loads in suspended sediments were lower at the downstream 

site during the first study year, with a slightly higher load 

downstream in the second year though the increase from 

upstream to downstream was small. Event-based yields were 

higher at the upstream site, indicating that readily available 

sediment sources are closer to the upstream site where more 

mining affected areas are located. The estimates determined 

during large precipitation events indicate that large sources of 

suspended sediments with large concentrations of trace elements are still available for transport within the Big River.

Introduction

Missouri was the leading producer of lead in the world 

for more than a century (Missouri Department of Natural 

Resources, 2014). An important source of lead was the Old 

Lead Belt, a sub district of the Southeast Missouri Lead 

District, located primarily in St. Francois County in southeastern Missouri (fig. 1). Galena was the primary ore mineral 

and could be found on surface outcrops and as deposits that 

extended nearly 200 feet vertically and thousands of feet laterally. Lead mining began in southeastern Missouri in the early 

1700s, at which time mines were mostly shallow pits operated 

by French explorers, and continued as individual small operations until the mid-1860s (Missouri Department of Natural 

Resources, 2014). In 1864, the St. Joseph Lead Company 

acquired 964 acres and began mining at Bonne Terre, Missouri 

(fig. 1). With the implementation of diamond-bit core drilling, 

lead deposits deep beneath the surface were discovered under 

much of the Big River Basin. Fifteen companies had mining 

operations in the Old Lead Belt by the early 1900s. Mining 

operations were gradually shut down during the late 1950s and 

early 1960s as ore deposits were depleted and mining in other 

parts of the State was more productive. More than 8.5 million 

tons of lead were produced from the Old Lead Belt before the 

St. Joseph Lead Company closed operations in 1972 (Missouri 

Department of Natural Resources, 2014). Although active lead 

mining ended more than 40 years ago, the effects of mining 

still remain within the region in the form of mining waste 

(tailings and chat) piles on the land surface. These piles are 

generally located near tributaries and the main stem of the Big 

River and are readily available sources of lead-rich suspended 

sediments that can enter into the watershed during runoff and 

by wind transport. 

The Big River is the main riverine system that drains 

the Old Lead Belt. The Big River runs generally south to 

north and is 145 miles in length from its source to the confluence with the Meramec River (fig. 1). Data collection during 

previous U.S. Geological Survey (USGS) investigations, in 

cooperation with Missouri Department of Natural Resources 

(MDNR), indicated that streambed sediments collected in the 

Meramec River downstream from the Big River have higher 

lead concentrations than those collected upstream from the 

Big River confluence (U.S. Geological Survey, 2015). These 

results indicate that lead-rich suspended sediments have been 

transported from the Big River in the past, but limited information is currently (2015) available to determine the amount 

of suspended sediments associated with mining wastes that are 

readily available for transport by the Big River through fluvial 

processes and whether these suspended sediments still contain 

mining-related metals. Additional information was needed to 

quantify daily sediment loads and the concentrations of lead 

and other metals of concern during stormflow events within 

the Big River Basin. Such information can assist regulatory 

agencies such as the U.S. Environmental Protection Agency 

(EPA) and the U.S. Fish and Wildlife Service (USFWS) in 

determining impaired reaches and ecosystems for remedial and 

restoration efforts. A study was performed by the U.S. Geological Survey in cooperation with U.S. Environmental Protection 

Agency, Region 7, to assess the amount and availability of 

suspended sediments within the Big River Basin after chat pile 

capping efforts ended in 2012 that completed a 4-year reclamation effort, and to assess the trace-element concentrations 

of suspended sediments transported through the basin. 

Study Background

Although mining activities are not currently (2015) being 

conducted in the Big River Basin, six large chat piles consisting of approximately 2,800 acres (Mosby and Weber, 2009) 

remain on the land surface upstream from the study reach that 

is located between two USGS streamgages (fig. 1). These large 

amounts of mine waste, sometimes spanning more than a mile 

in diameter, began with the introduction of industrial-grade 

mining and milling methods in the early 1900s. Materials 

excavated from below the land surface were crushed or ground 

using jig tables in the earlier periods, and after the 1920s 

chemical flotation techniques were used to separate lead from 

the host rock. The leftover host rock was discarded into chat 

(larger pieces from crushing) or tailings (smaller material from 
Introduction 3

Figure 1. Location of study sites and the Big River Basin.

JEFFERSON

FRANKLIN

CR

AWFO

R

D

IRON

MADISON

ST LOUIS

WASHINGTON

Byrnes

Mill

Cedar

Hill

Hillsboro

Potosi

Bonne

Terre

Desloge

Leadwood

Irondale

Bonne Terre

Leadwood

Desloge

National

Elvins

Federal

Federal

07017610

07018500

MISSOURI

ILLINOIS

Big River

Big River

Mineral Fork

Meramec River

Mill Creek

Cedar Creek

Flat Creek

Mississippi River

Meramec River

#

#

38°30’

38°

91° 90°30’

0 10 20 MILES

0 10 20 KILOMETERS

STUDY AREA

MISSOURI

St. Louis

#

Mine waste pile and name

U.S. Geological Survey streamflow-

 gaging station site number

Big River Basin

Old Lead Belt mining district

EXPLANATION

Base from U.S. Geological Survey digital data 1:24,000, 1999

Universal Transverse Mercator Projection

Zone 15

Byrnesville

ST FRANCOIS

STE

GENEVIEVE

07017610
4 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

the flotation process) piles. Neither method was completely 

effective at separating ore from host rock. Some operations 

would re-mill existing chat piles to recover lead missed from 

basic crushing methods (Missouri Department of Natural 

Resources, 2014). These piles have resulted in a source of suspended sediments available for transport by natural erosional 

processes such as storm event runoff and wind into the Big 

River. Between 2008 and 2012, the EPA conducted reclamation efforts to cap and prevent further erosion of the piles 

(Mosby and Weber, 2009). 

Previous USGS studies have determined surface-water 

quality, and physical and chemical processes related to the 

quality of water, trace-element concentrations of suspendedsediment and streambed-sediment particles of various sizes, 

and loads of select trace elements in dissolved and solid 

phases (Smith and Schumacher, 1991, 1993); however, limited 

information is available on the current (2015) amount of 

suspended sediments transported through the Big River as 

well as the concentration of trace elements in suspended sediments. As capping efforts have been made to restrict additional 

sediment sources, it is important to determine the amount of 

suspended sediments and the trace-element concentrations of 

these suspended sediments that are still available for transport 

through the basin as well as to assess the effectiveness of the 

reclamation efforts over time.

Sediments are fragments of parent materials that have 

been affected by erosional processes and are transported 

by, suspended in, or deposited by water or air, and also can 

accumulate in beds (Edwards and Glysson, 1999). The USGS 

defines sediments transported by water as “fluvial sediments.” 

Fluvial sediments are fragmented material derived from 

weathering of larger rocks and transported by, suspended in, or 

deposited by water, and can include biological and chemical 

precipitates and decomposed organic materials (Edwards and 

Glysson, 1999). Finer-grained fluvial sediments are transported in suspension because of the velocity and currents of 

the stream, whereas coarser sediments are transported closer 

to the streambed by rolling and skipping along the streambed. 

The finer, suspended particles tend to be transported at the 

same rate that the stream flows, whereas the coarser materials are only transported when the system experiences higher 

velocities and generally are at rest most of the time (Edwards 

and Glysson, 1999). The supply of finer materials in suspension (also known as the “wash load”) usually has a greater 

effect on the suspended-sediment concentration (SSC) than 

streamflow conditions, because the rate of supply varies 

during and between events as well as from seasonal precipitation and vegetation (Charlton, 2008). Increases in streamflow 

produce increased SSC as erosion increases, releasing finer 

particles from storage. The computation of daily SSC and 

suspended-sediment load (SSL) is useful in various applications such as describing variability in suspended-sediment 

conditions, evaluating water-resource management practices 

and goals, predicting reservoir capacities, evaluating waterquality criteria, understanding stream channel morphology, 

and comparing sediment characteristics between basins (Rasmussen and others, 2009).

Turbidity is a qualitative parameter defined by an optical 

measurement of scattered and absorbed light as it interacts 

with solid particles through a fluid sample, and measurements 

are expressed in units based on the technology used as well as 

the calibration standards (ASTM International, 2011). Suspended and dissolved organic and inorganic materials such 

as sediments (sands, silts, and clays), algae, microorganisms, 

organic acids, and dyes are common causes of turbidity in 

fluvial systems. Turbidity can assist with the computation of 

time-series SSC, monitoring land use and other human-related 

activities, and natural resource restoration (Anderson, 2005). 

Trace element concentrations are related to sediments in 

streams by a number of factors including grain size, surface 

area, and sediment composition (Horowitz and Elrick, 1987). 

As the proportion of grain size increases, the trace element 

concentrations associated with the sediments also increase. 

The surface area of the grains also affects the concentration 

of trace elements as a larger surface area allows for stronger 

bonding, most commonly in sediment size fractions less than 

0.063 millimeters (mm). When an abundance of very finegrained sediments are present, the particles can attach together 

creating aggregates, which increase the mean grain size of a 

sample and reduces available surface area. The aggregates of 

sediments less than 0.063 mm can affect trace element concentrations in a sample more than larger size fractions of sands 

(Horowitz and Elrick, 1987).

Purpose and Scope

The purpose of this report is to present the results of 

a hydrologic investigation to characterize and calculate 

suspended-sediment quantity and quality being transported 

through the lower Big River, Mo., based on data collected 

October 2011 through September 2013. The report describes 

the techniques and methods used to collect and analyze waterquality constituents such as water temperature and turbidity; 

suspended-sediment concentration, load, and particle-size 

distribution; and selected trace-element concentration load in 

sediments at two sites on the main stem of the Big River during stormflow events. 

Description of Study Area

The area of study is a 68-mile reach of the Big River, 

between the towns of Bonne Terre and Byrnes Mill, Mo. 

(fig. 1; table 1). Two sites were used in this study: Big River 

below Bonne Terre, Mo. (USGS site number 07017610; 

hereinafter referred to as the upstream site) and Big River at 

Byrnesville, Mo. (USGS site number 07018500; hereinafter referred to as the downstream site). The upstream site is 

located less than 5 miles downstream from the Old Lead Belt, 

and the downstream site is located about 68 miles downstream 
Methods 5

from Bonne Terre. The Big River discharges into the Meramec 

River, approximately 15 miles downstream from the downstream site. The Meramec River discharges into the Mississippi River south of St. Louis, Mo. The study area is located 

within the Salem Plateau of the Ozark Plateaus physiographic 

province (Fenneman, 1938). The topography of the upper 

reaches of the study area is rugged with narrow, steep drainage 

divides and several hundred feet of relief. The lower reaches 

also have some steep drainage that gradually transition to 

large flood plains. Land-surface altitudes range from about 

400 to 1,000 feet (ft) above North American Vertical Datum of 

1988 (NAVD 88). Stream width is generally 50 ft in the upper 

reaches of the basin and can span nearly 100 ft in the lower 

reaches. The streambed consists mainly of coarse materials 

such as cobbles, gravels, and sands in the upper reaches and 

smaller-grained particles such as sands and silts in the lower 

reaches. Land use in the Big River Basin is approximately 

72 percent forest, 18 percent grassland, 7 percent urbanized or 

developed, and 1 percent cropland (Missouri Department of 

Natural Resources, 2013). Some low-head mill dams are still 

present, which can alter and control the streamflow. Tributaries along the Big River include Cedar Creek, Flat Creek, Mill 

Creek, and Mineral Fork. Mineral Fork, the largest tributary 

with a basin area of 189 square miles (mi2; Missouri Department of Natural Resources, 2013), discharges into the Big 

River between the two study sites. No streamflow-gaging 

station (hereinafter referred to as streamgage) is located on 

Mineral Fork or the other tributaries in the basin.

Methods

In order to quantify the transport of sediment and the concentration and flux of selected metals in the Big River, streamflow and suspended sediments were quantified and sampled at 

the two study sites. All field and laboratory methods described 

in this report were consistently performed at both sites during 

the study period. Any variations have been documented and 

described fully within this study report.

Field Methods

The upstream site was established for this study and 

began operation on October 13, 2011. The site is located at 

the bridge on County Highway E, approximately 3 miles 

north of Bonne Terre (fig 1; table 1). The drainage area of the 

upstream site is 409 mi2. The pressure transducer orifice line 

and continuous water-quality monitor (CWQM) are deployed 

from the left stream bank (facing downstream) under the 

highway bridge. During base-flow conditions, streamflow 

measurements and suspended-sediment samples were obtained 

approximately 40 ft upstream from the streamgage. Measurements and samples during high-flow conditions (hereinafter 

referred to as “event sampling”) were collected from the 

bridge deck on Highway E. The stream channel at this site 

location is relatively shallow and narrow (2 to 3 ft deep and 

60 ft or less wide) and the streambed consists of fine sands, 

gravels, large cobbles, and some boulders. 

The downstream site has been an active streamgage from 

May 1922 to present (2015); is located on the left edge of the 

water on a privately owned bridge near Old Byrnesmill Road 

in Byrnesville, Mo.; and has a drainage area of 917 mi2 (fig 1; 

table 1). The CWQM was deployed from the left side of the 

stream along a rock bluff just under the bridge, next to the orifice line. The streamgage is approximately 100 ft downstream 

from an old low-head mill dam. During base-flow conditions, 

streamflow measurements and suspended-sediment samples 

were obtained by wading approximately 300 ft downstream 

from the streamgage, which is downstream from the bridge 

on Old Byrnesmill Road. If wading conditions were not safe, 

measurements and samples were collected from the bridge 

on Old Byrnesmill Road, which was the location of all event 

sampling. The stream channel at the wading section is usually 3 to 5 ft deep and 80 to 100 ft wide, and the streambed 

consists primarily of gravels and coarse sands with some finer 

sands and silts. 

Study sites were equipped with a data collection platform (DCP) that stored information from the non-submersible 

pressure transducer used for measuring stream stage and from 

Table 1. Location information for study sites on the Big River, Missouri.

[USGS, U.S. Geological Survey; mi2, square miles; in., inches]

USGS 

site 

number 

(fig. 1)

Station name

Study 

location 

description

Latitude

(degrees/

minutes/

seconds)

Longitude

(degrees/

minutes/

seconds)

Drainage 

area 

(mi2)

County

Average 

monthly 

precipitation1

(in.)

Period of streamflow record used in 

this study

07017610 Big River below 

Bonne Terre, 

Missouri

upstream 37°57′55.9′′ 90°34′27.9′′ 409 St. Francois 3.6 October 2011– 

September 2013

07018500 Big River at 

Byrnesville, 

Missouri

downstream 38°23′30.2′′ 90°38’16.1′′ 917 Jefferson 3.2 May 1922–

September 2013

1

Average monthly precipitation was computed using only monthly precipitation data within the study period (October 2011 through September 2013).
6 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

the CWQM used to measure water temperature and turbidity. 

Stream stage, water temperature, and turbidity were recorded 

by the DCP every 15 minutes and transmitted hourly by way 

of satellite telemetry. All water-quality data were archived 

along with streamflow data in the USGS National Water Information System (NWIS; U.S. Geological Survey, 2015). The 

CWQMs were deployed using polyvinyl chloride (PVC) pipe. 

The PVC pipe had multiple 1-inch (in.) holes drilled to allow 

water from the stream to flow freely around the instrument, 

reducing bias in data from readings of stagnant water trapped 

in the pipe. 

Instantaneous streamflow measurements were made 

every 4 to 6 weeks at the two sites and during event sampling 

to determine and maintain a stage-discharge relationship using 

standard USGS methods and techniques (Rantz and others, 

1982; Sauer, 2002; Oberg and others, 2005; Turnipseed and 

Sauer, 2010; Mueller and others, 2013). Instantaneous measurements were made with various acoustic doppler current 

profilers (ADCP) by wading during low-flow conditions and 

from the bridge decks during high flows or if the wading sections could not be accessed safely. 

Water temperature was recorded in degrees Celsius (°C) 

and turbidity was reported in formazin nephelometric units 

(FNU). Thermistors used for water temperature measurements 

were checked against a National Institute of Standards and 

Technology (NIST) calibrated thermometer and received at 

minimum a 3-point calibration check as documented in Wilde 

(2006). Many different sensors and models of turbidometers 

are available for field measurements. For this study, a YSI 

Incorporated sensor model 6136 (YSI 6136) was used to 

record instantaneous turbidity readings at both sites as well 

as the field meter to reduce any bias between sensor makes or 

models. The advantage of the YSI 6136 is that erroneous readings are reduced because the sensor is equipped with a wiper. 

For the purpose of this study, only suspended sediments 

were collected. Suspended-sediment loads described in this 

study are considered to represent the majority of sediments 

transported in suspension within the Big River and are referred 

to as SSL. No bedload sampling was performed; therefore, any 

loads computed from the results are not intended to be considered a total sediment load. 

Cross-sectional (discrete) suspended-sediment samples 

were collected during stormflow events and almost every 

month during base-flow conditions. Uses of the suspendedsediment samples were two-fold—to determine a relation with 

turbidity data to compute a daily SSC (that is, calibrate the 

regression model), and to measure trace-element concentrations of the suspended sediments being transported during a 

stormflow event. Stormflow events were defined in this study 

as a rapid and substantial change in streamflow and turbidity. 

The magnitude and duration of stormflow events varied and 

collection efforts were not always successful or possible. 

The monthly suspended-sediment collections at base flow 

were collected by wading in the stream and using a depth-integrated and isokinetic (stream water approaching and entering 

the sampling nozzle have the same velocity) sampler known as 

a US DH-81 sampler. The US DH-81 contained a rigid, polyethylene 1-liter (L) sampling bottle and one-quarter in. Teflon® 

nozzle. The equal-width increment (EWI) sampling method 

was used to obtain the sediment sample as described in Wilde 

and others (2004). The sampler was raised and lowered at a 

consistent transit rate at each sampling interval (vertical). If 

multiple 1-L bottles were used to collect at all verticals, the 

bottles were composited by the laboratory for analysis. If the 

minimum mean stream velocity was less than 1.5 feet per 

second (ft/s), isokinetic conditions no longer existed, and baseflow samples were collected using grab sampling methods as 

described in Wilde and others (2004).

If stream conditions were not conducive to wading 

because of depth, debris, high velocities, or other conditions 

that made wading dangerous, suspended-sediment samples 

were collected from the bridge deck at each site. The samplers were attached to a reel and cable mechanism on either a 

3-wheeled base or a crane structure mounted to the front of a 

field vehicle. The reel was hand-operated at a constant speed 

based on the transit rate computed by the maximum velocity and depth. A one-quarter in. nozzle was used to collect all 

particles classified as sand-sized and smaller. Collection was 

performed using the same EWI techniques used for base-flow 

sampling except with a heavier sampler to maintain isokinetic 

sampling requirements (Wilde and others, 2004). Depending 

on the average stream depth and velocities during stormflow 

events, either a US DH-95 or US DH-2 sampler was used. 

Descriptions of each sampler and the limitations of each are 

described in Wilde and others (2014). Samples were collected 

at multiple points along the hydrograph, including the rising limb, the event peak, and the falling limb, when possible. 

Streamflow measurements also were collected as close to 

the peak as possible. The suspended-sediment concentration 

samples along the hydrograph were analyzed individually to 

compute the concentration flux throughout the event. Samples 

to be analyzed for trace-element concentrations were collected 

using the clean hands/dirty hands techniques as described in 

U.S. Geological Survey (2006). 

Samplers used by the USGS, as recommended by the 

Federal Interagency Sedimentation Project (FISP) for the collection of suspended sediments (Davis, 2005), cover a wide 

range of sampling capacities and conditions and have a limitation on the depth within the water column at which sampling 

can occur, based on the nozzle size and location in relation 

to the bottom of the sampler. The portion of depth near the 

streambed that cannot be reached by the nozzle is called the 

unsampled zone and can carry a higher concentration and 

coarser-sized sediment, which may or may not account for a 

large portion of the total suspended sediment, depending on 

stream velocity, depth, and turbulence through the sampled 

vertical (Edwards and Glysson, 1999). The concentration 

obtained within the measured depth is nearly equal to the 

concentration in the unsampled zone, as noted in Edwards 

and Glysson (1999), if the velocity and turbulence within 

the sampled depth are efficiently keeping sediments suspended within the total depth and are greater than the forces 
Methods 7

transporting sediments along the streambed in the unsampled 

zone. The USGS samplers used in this study had unsampled 

zones of 4 in. for the DH-81 and DH-2 and 4.8 in. for the 

DH-95 (Davis, 2005; Wilde and others, 2014).

Laboratory Methods

All suspended-sediment samples were processed at the 

USGS Missouri Water Science Center Sediment Laboratory in 

Rolla, Mo. Samples were delivered to the lab within 5 days of 

collection. Base-flow samples were analyzed for SSC in milligrams per liter using a filtration method as described in Guy 

(1969). All SSC results are available on NWISWeb at http://

waterdata.usgs.gov/mo/nwis/qw.

Event samples were analyzed for SSC as well as particle size distribution of the sands (sediments greater than 

0.063 mm) and fines (sediments less than 0.063 mm) fractions. 

Samples collected during events were sieved using techniques described in Guy (1969). Sieve mesh with openings of 

approximately 0.0625 mm and made of nylon fibers was used 

to reduce possible trace-element contamination from using 

traditional brass or stainless steel mesh sieves. All sediments 

in the sample were washed through the mesh sieve using 

deionized water. Fines which passed through the sieve were 

captured in a glass dish. All sediments remaining on the sieve 

mesh were rinsed into a separate glass dish, then both fractions 

were dried at 80 °C until all visible water was evaporated, 

followed by additional drying at 103 °C for one hour (Guy, 

1969). If the mass for either sieved fraction was greater than 

or equal to 0.25 grams (g), the fraction could be analyzed for 

trace-element concentrations at the USGS Minerals Research 

Laboratory (MRL) in Denver, Colorado. 

Dried fractions for trace-element analyses were shipped 

to the USGS MRL in glass vials. A suite of 42 trace elements 

was measured by inductively-coupled plasma mass-spectrometry (ICP-MS) using an acid digestion using documented 

laboratory methods (Taggart, 2002). Trace elements analyzed 

for this study as well as sediment analyses and the reporting 

limits are listed in table 2. All trace-element concentrations for 

each size fraction were stored in NWIS and are available at 

http://waterdata.usgs.gov/mo/nwis/qw.

Quality Assurance and Quality Control

Quality assurance consists of techniques and practices 

used within a study to meet defined levels of quality with a 

known level of confidence to ensure the most accurate data 

possible. Such practices begin with site and equipment selection, sampling and maintenance frequencies and methods, 

personnel training and safety, and laboratory selection, all of 

which ensure the goals of the study are met. A USGS internal 

quality-assurance plan, summarized in this section, was created and used to document techniques and methods specific 

to the study with USGS guidelines. Data transmissions to 

NWISWeb were reviewed daily to remove erroneous data 

quickly and efficiently from the sensor record. Documentation 

of service visits and the calibration of the CWQM were 

archived and describe actions taken during the visit. Sediment 

sampling documentation also was archived and describes 

sampling conditions, sample type, sampling methods, equipment used, and other information as needed. Laboratory 

analysis request forms were used for both the sediment lab and 

the USGS MRL to document and track the samples and the 

analyses. 

Data transmitted from the DCP at each site were 

reviewed daily for consistency and for determining the need 

for event sampling. CWQMs were serviced and calibrated 

following USGS guidelines as described in Wagner and others 

(2006). Construction setup and monitor selection was determined during reconnaissance before the start of the project 

to reduce effects of fouling, low-flow conditions, and damage from flooding or vandalism, and to guarantee safety in 

accessing the equipment. CWQMs were serviced on at least 

a monthly schedule and additionally when the data appeared 

erratic or anomalous. The monitors were cleaned, inspected 

for damage, and checked for calibration drift. If the calibration drift was greater than USGS criteria, the sensors were 

recalibrated. If the fouling or calibration drift was greater than 

USGS criteria as stated in Wagner and others (2006), the data 

were removed from the record. 

Efforts were made to minimize contamination from 

sampling equipment, surrounding structures, and vehicles during event sampling. The clean hands/dirty hands technique as 

described in U.S. Geological Survey (2006) was used throughout the sampling procedures at a site. Containers for sample 

compositing were kept sealed and protected in a large plastic 

bag to prevent contamination by airborne debris caused by 

wind, vehicle traffic, the sampling crane, bridge railings, and 

precipitation.

Quality-control samples help identify and quantify bias 

and variability in sampling techniques such as sampling 

equipment, processing, shipping, and handling of the sample 

(U.S. Geological Survey, 2006). During the study, qualitycontrol samples were collected in the form of replicate suspended-sediment samples and laboratory blanks. A sequential 

replicate sample (collected in the same order after the environmental sample and composited into a second container) 

was performed when possible. Blank samples using deionized 

water processed by the USGS Missouri Water Science Center 

Sediment Laboratory were randomly assigned to sample shipments during the login phase for internal laboratory validation 

and quality assurance. USGS Sediment Laboratories participate in bi-annual quality-assurance tests to document inconsistencies within each lab and among all USGS labs for consistency in reporting results. Quality-assurance test results for the 

USGS Missouri Water Science Center Sediment Laboratory 

are available at the USGS Branch of Quality Systems at http://

bqs.usgs.gov/SLQA/. The USGS MRL created laboratory split 

replicates for 10 percent of a shipment to validate laboratory 

results for internal quality assurance and are available upon 

request from the USGS MRL at http://minerals.cr.usgs.gov/.
8 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Table 2. Reporting limits of laboratory analyses.

[%, percent; USGS SMRL, U.S. Geological Survey Minerals Research Laboratory; mg/L, milligrams per liter; 

mm, millimeters; USGS SDMO, U.S. Geological Survey Missouri Sediment Laboratory; --, not available]

Constituent Reporting 

limit

Analyzing 

laboratory

Analytical 

reference

Aluminum, Al 0.01% USGS SMRL Taggart, 2002

Calcium, Ca 0.01% USGS SMRL Taggart, 2002

Iron, Fe 0.01% USGS SMRL Taggart, 2002

Potassium, K 0.01% USGS SMRL Taggart, 2002

Magnesium, Mg 0.01% USGS SMRL Taggart, 2002

Sodium, Na 0.01% USGS SMRL Taggart, 2002

Phosphorous, P 50 mg/L USGS SMRL Taggart, 2002

Titanium, Ti 0.01% USGS SMRL Taggart, 2002

Silver, Ag 1 mg/L USGS SMRL Taggart, 2002

Arsenic, As 1 mg/L USGS SMRL Taggart, 2002

Barium, Ba 5 mg/L USGS SMRL Taggart, 2002

Beryllium, Be 0.1 mg/L USGS SMRL Taggart, 2002

Bismuth, Bi 0.04 mg/L USGS SMRL Taggart, 2002

Cadmium, Cd 0.1 mg/L USGS SMRL Taggart, 2002

Cerium, Ce 0.05 mg/L USGS SMRL Taggart, 2002

Cobalt, Co 0.1 mg/L USGS SMRL Taggart, 2002

Chromium, Cr 1 mg/L USGS SMRL Taggart, 2002

Cesium, Cs 0.05 mg/L USGS SMRL Taggart, 2002

Copper, Cu 0.5 mg/L USGS SMRL Taggart, 2002

Gallium, Ga 0.05 mg/L USGS SMRL Taggart, 2002

Indium, In 0.02 mg/L USGS SMRL Taggart, 2002

Lanthanum, La 0.5 mg/L USGS SMRL Taggart, 2002

Lithium, Li 1 mg/L USGS SMRL Taggart, 2002

Manganese, Mn 5 mg/L USGS SMRL Taggart, 2002

Molybdenum, Mo 0.05 mg/L USGS SMRL Taggart, 2002

Niobium, Nb 0.1 mg/L USGS SMRL Taggart, 2002

Nickel, Ni 0.5 mg/L USGS SMRL Taggart, 2002

Lead, Pb 0.5 mg/L USGS SMRL Taggart, 2002

Rubidium, Rb 0.2 mg/L USGS SMRL Taggart, 2002

Sulfur, S 0.01% USGS SMRL Taggart, 2002

Antimony, Sb 0.05 mg/L USGS SMRL Taggart, 2002

Scandium, Sc 0.1 mg/L USGS SMRL Taggart, 2002

Tin, Sn 0.1 mg/L USGS SMRL Taggart, 2002

Strontium, Sr 0.5 mg/L USGS SMRL Taggart, 2002

Tellurium, Te 0.1 mg/L USGS SMRL Taggart, 2002

Thallium, Tl 0.1 mg/L USGS SMRL Taggart, 2002

Thorium, Th 0.2 mg/L USGS SMRL Taggart, 2002

Uranium, U 0.1 mg/L USGS SMRL Taggart, 2002

Vanadium, V 1.0 mg/L USGS SMRL Taggart, 2002

Tungsten, W 0.1 mg/L USGS SMRL Taggart, 2002

Yttrium, Y 0.1 mg/L USGS SMRL Taggart, 2002

Zinc, Zn 1 mg/L USGS SMRL Taggart, 2002

Suspended-sediment concentration (SSC) 0.5 mg/L USGS SDMO Guy, 1969

Suspended sediment, percent finer than 0.063 mm 0% USGS SDMO Guy, 1969
Methods 9

Data Analysis and Reporting

Streamflow and water-quality constituent statistics were 

derived from daily mean, monthly mean, or annual mean 

values. The mean values were derived from the 15-minute 

data. Annual runoff was derived by dividing the annual mean 

streamflow in cubic feet per second by the drainage area 

in square miles, then multiplying by a conversion factor of 

13.5744 to obtain the result in inches per water year. Monthly 

precipitation accumulations were obtained for weather stations 

near the study sites from the National Oceanographic and 

Atmospheric Administration (NOAA) and are cumulative precipitation measurements converted from millimeters to inches 

for consistency of units within the report.

Daily values of continuous water temperature and turbidity were published in the “Annual Water Year Summary 

Reports,” which can be accessed through NWISWeb, along 

with other daily, monthly, and annual statistics (U.S. Geological Survey, 2015). Periods of missing data occurred because 

of extreme biological fouling such as algae and macroinvertebrates, siltation after large events, or extreme low-flow conditions. Turbidity values were used in a regression model for the 

computation of daily SSC. Because the magnitude of turbidity 

in fluvial systems is usually proportional to SSC (Rasmussen and others, 2009), continuous turbidity measurements 

also could be used to determine if a stormflow event was 

large enough to transport the minimum amount of suspended 

sediments required for the sediment chemistry analyses at the 

USGS MRL (0.25 grams).

A regression model for the computation of time-series 

SSC and SSL values was developed for each site using a 

dataset of discrete SSC and corresponding time-series turbidity and (or) streamflow. The dataset was used to calibrate the 

model and identify outliers and trends. Outliers were reviewed 

for erroneous entries, sampling method problems, or laboratory errors. For robust model development, the number of 

data pairs as well as the distribution of data over observed 

hydrologic conditions during the study is important (Rasmussen and others, 2009). The monthly base-flow sampling in 

combination with the multiple event values over a range of 

streamflows and turbidity measurements allowed for greater 

confidence in the model development for each site. Duration curves (fig. 2) show turbidity measurements at both sites 

were within the limits of the maximum level of accuracy 

(1,000 FNU) of the sensor model for all days in the study 

period except one. 

During the 2012 water year (a water year is defined as a 

12-month period beginning October 1 and ending September 

30, designated by the calendar year in which it ends), 27 discrete SSC samples were collected and available for the model 

development at the upstream site. Non-transformed values of 

SSC were plotted against turbidity to determine if a statistically strong relationship existed (Rasmussen and others, 

2009). Four outliers were detected by graphical inspection of 

the raw data and residual plots. The outliers occurred during 

storm events: two event SSC results collected on April 16, 

2012; one sample on April 17, 2012; and one sample on September 8, 2012. The instantaneous turbidity values likely were 

biased from extreme fouling during the events rather than 

sediment sampling errors because when the CWQM could be 

accessed safely afterwards, the guard and deployment pipe 

were noted to be filled with gravel and mud. The four outliers 

were removed from the dataset. The remaining 23 data pairs 

were then plotted on a log-log scale to determine the strongest 

statistical relationship. The best-fit relation was determined to 

be from the power function, having an adjusted coefficient of 

determination (R2

a

) value of 0.92 and a level of significance 

(p-value) of 0.0043. During the 2013 water year, 13 discrete 

SSC results were added to the 2012 dataset to continue the 

regression model for the entire study period. No outliers were 

found in the 2013 water year dataset. The total dataset used in 

the study model for the upstream site included 36 pairs of data 

(table 3; fig. 3). 

Figure 2. Turbidity duration curves for two study sites on the Big River, Missouri, October 2011–September 2013.

1

10

100

1,000

10,000

0 10 20 30 40 50 60 70 80 90 100

1

10

100

1,000

10,000

0 10 20 30 40 50 60 70 80 90 100

Turbidity, 

in formazin nephelometric units

Big River below Bonne Terre, Missouri 

(07017610; upstream site)

Big River at Byrnesville, Missouri 

(07018500; downstream site)

Percent of exceedance

YSI, Inc. 6136 turbidity sensor's maximum for accuracy YSI, Inc. 6136 turbidity sensor's maximum for accuracy
10 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

The final regression model for the upstream site, Big 

River below Bonne Terre (USGS Identifier 07017610), for the 

study period is as follows:

SSC = 1.8239(Turb)0.984 (1)

where

SSC is suspended-sediment concentration, in 

milligrams per liter; and

Turb is turbidity, in formazin nephelometric units, 

measured with a YSI model 6136.

The model information used to develop equation 1 is as 

follows:

• Number of measurements = 36

• Residual standard error = 0.239

• Degrees of freedom = 33

• Adjusted coefficient of determination (R2

a

) = 0.92

The downstream site had 19 SSC samples available for 

the development of the 2012 water year model. As was determined upstream, the SSC and turbidity data plotted in log-log 

scale made the best-fit relation at the downstream site using 

the power function, with an R2

a

 value of 0.89 and a p-value of 

0.0198. During model evaluation, three outliers were detected 

within the 2012 dataset—a routine base-flow collection on 

November 10, 2011; an event collection on March 17, 2012; 

and a routine base-flow collection on April 4, 2012. The SSC 

result for the November sampling date seemed to be biased 

high in relation to the turbidity results. The SSC sampling 

process may have inadvertently struck the sandy streambed, 

creating a re-suspension of bed materials. The March sample 

was during an event and could have been biased high during 

SSC collection or a possible turbidity sensor issue. The April 

outlier could have been because of a low-biased SSC collection (sampling rate too fast for the velocity) or erroneous 

turbidity readings. These three data points did not fit the general trend of the remaining points and were therefore removed 

from the dataset. 

Paired SSC and instantaneous turbidity data collected 

at the downstream site during water year 2013 were added 

to the 2012 dataset to continue the regression model for the 

entire study period. Twelve data points were available from 

2013; however, during model calibration and evaluation, three 

outliers were detected: January 31, 2013; April 20, 2013; and 

May 28, 2013. The January and April sampling dates had 

reasonable SSC results but because of extreme flooding and 

fouling of the turbidity sensor, no turbidity data were available 

Table 3. Summary statistics of model-calibration datasets for two study sites on the Big River, October 2011–September 2013.

[FNU, formazin nephelometric units; mg/L, milligrams per liter; ft3/s, cubic feet per second; --, not applicable]

Statistical summary of datasets

Summary statistic Turbidity 

(FNU)

Model dataset Time-series dataset (17,240 hourly values)

Suspended-sediment 

concentration (mg/L)

Streamflow 

(ft3/s) Turbidity (FNU) Streamflow (ft3

/s)

 Big River below Bonne Terre, Missouri (07017610; upstream site)

Minimum 1.2 1 16 1 7.2

Maximum 840 1,090 18,600 880 21,900

Mean 117 170 2,840 15 450

Median 46 74 637 6.2 130

Standard deviation 196 230 5,530 44 1,510

Number of unavailable turbidity 

values

1 -- -- 2,214 --

Number of data used in model 36 36 -- -- --

Big River at Byrnesville, Missouri (07018500; downstream site)

Minimum 3.1 4 61 0 51

Maximum 790 870 24,600 715 28,280

Mean 65 130 2,023 13 920

Median 8.7 21 410 6.6 340

Standard deviation 160 235 4,939 29 2,430

Number of unavailable turbidity 

values

0 -- -- 1,139 --

Number of data used in model 25 25 -- -- --
Methods 11

for comparison. The May sample had erroneous turbidity data 

because of extreme biofouling around the deployment pipe, 

and data were removed from the record. The total dataset used 

in the study model for the downstream site included 25 pairs 

of data (table 3; fig. 3). The model calibration remained statistically strong with the dataset of the full study period (seven 

outliers still removed), using the non-transformed SSC and 

turbidity data. 

The final regression model for the downstream site, Big 

River at Byrnesville (USGS Identifier 07018500) for the study 

period is as follows:

SSC = 1.786(Turb)

1.050 (2)

where

SSC is suspended-sediment concentration, in 

milligrams per liter; and

Turb is turbidity, in formazin nephelometric units, 

measured with a YSI model 6136.

The model information used to develop equation 1 is as 

follows:

• Number of measurements = 25

• Residual standard error = 0.236

• Degrees of freedom = 23

• Adjusted coefficient of determination (R2

a

) = 0.89

The regressions were applied to each instantaneous 

turbidity measurement available during the study period 

to compute time-series SSCs. The instantaneous turbidity 

measurements were stored in the NWIS subsystem ADAPS 

(automated data processing system), where mean daily SSC 

values also were computed and archived. The mean daily 

SSC values were then used to compute daily SSL values, also 

archived in ADAPS.

If no turbidity data were available or if the turbidity 

data were deemed unusable for sediment computation, a 

daily mean SSC value was computed using streamflow. The 

relationship was determined using similar techniques as SSCturbidity relationship analyses. Daily SSC results from the 

SSC-turbidity relationship were plotted against daily streamflow for the period of record available. Data were transformed 

until a best-fit relationship was determined. A best fit for 

both sites during the study was determined by plotting SSC 

and daily streamflow on a log-log scale (fig. 4). The SSCstreamflow relationship was not as statistically accurate as the 

SSC-turbidity relationship, and all daily SSC values computed 

using streamflow were flagged as estimated. SSL values computed from estimated SSC data also were flagged as estimated. 

The estimated daily SSC equation for the upstream site, Big 

River below Bonne Terre (USGS identifier 07017610), is as 

follows:

SSC = 0.3341(Q)

0.8148 (3)

where

SSC is suspended-sediment concentration, in 

milligrams per liter; and

Q is daily mean streamflow, in cubic feet per 

second.

Figure 3. Instantaneous turbidity in relation to discrete 

suspended-sediment concentrations used to develop a regression 

model for the computation of daily suspended-sediment 

concentrations and loads for two study sites on the Big River, 

October 2011–September 2013.

0.1

1.0

10

100

1,000

5,000

0.1 1.0 10 100 1,000 5,000

Discrete suspended-sediment concentration, in milligrams per liter

Instantaneous turbidity, in formazin nephelometric units

y = 1.8239(x)

0.984

R 2

a

 = 0.92

n = 36

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

y = 1.786(x)

1.050

R 2

a

 = 0.89

n = 25

1

10

100

1,000

5,000

1 10 100 1,000 5,000

EXPLANATION

regression equation

R 2

a

 = 0.89

n = 25

y = 1.786(x)

1.050

R 2

a

 = adjusted coefficient of 

determination

n = number of datasets

where: y = suspended-sediment 

concentration and x = instantaneous turbidity

Data pair used in model

Best-fit regression model
12 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

The estimated daily SSC equation for the downstream site, Big 

River at Byrnesville (USGS identifier 07018500) is as follows:

SSC =0.1668(Q)0.8469 (4)

where

SSC is suspended-sediment concentration, in 

milligrams per liter; and

Q is daily mean streamflow, in cubic feet per 

second.

Event-based SSLs were computed using the event-average SSC and the sampled runoff volume. The average SSC 

was the arithmetic average determined from all samples collected during the event. In some cases, only one sample could 

be collected because of timing of arrival, equipment issues, 

magnitude of event and rapid rises, and other various reasons. 

The sample runoff volume was the sum of the incremental 

streamflow in 15-minute intervals within the designated event 

duration divided by the event duration time. Using the streamflow data, the beginning and ending of each event was determined based on each event’s increase or decrease in streamflow over time. The beginning of the event was established at 

the 15-minute streamflow value recorded one hour before the 

change in streamflow doubled. The end of the event varied by 

site and event because each event was unique in hydrologic 

conditions, but was determined when the streamflow was 

decreasing at a constant rate of 20 cubic feet per second (ft3/s) 

during each 15-minute measurement for at least 2 hours. The 

time between the established start and ending of the event was 

considered the event duration in hours. Event-based SSL was 

computed using the following equation:

ESSL = EMSSC x RV x (6.245 x 10-5) (5)

where

ESSL is event-based suspended-sediment load, in 

pounds;

EMSSC is event-based suspended-sediment 

concentration, in milligrams per liter;

RV is runoff volume, in cubic feet; and

6.245 x 10-5 is a conversion from milligrams per liter to 

pounds per cubic foot.

Sediment yield is the amount of material removed from 

the land surface by erosion in a given unit of time per unit area 

of the hydrologic basin. Sediment yield is a useful tool for 

comparing study sites because it removes variation in basin 

size and event duration by normalizing the SSL. Event-based 

yields were computed for this study using the following 

equation:

EYield = ESSL/ (DA x ED) (6)

where

EYield is event-based suspended-sediment yield, in 

pounds per square mile per hour;

ESSL is event-based suspended-sediment load, in 

pounds;

DA is drainage area, in square miles; and

ED is event duration, in hours.

Concentrations of barium, cadmium, lead, and zinc 

measured in suspended-sediment samples collected during 

events were used to compute event-based loads and yields of 

these constituents. In order to properly compute the traceelement concentration within the suspended sediments, a mass 

Figure 4. Daily mean streamflow in relation to discrete 

suspended-sediment concentrations used to develop a regression 

model for the computation of estimated daily suspended-sediment 

concentrations and loads for two study sites on the Big River, 

Missouri, October 2011–September 2013.

1 10 100 1,000 10,000 100,000

0.1

1

10

100

1,000

5,000

Discrete suspended-sediment concentration, in milligrams per liter

Daily mean streamflow, in cubic feet per second

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

10 100 1,000 10,000 100,000

1

10

100

1,000

5,000

y = 0.3341(x)

0.8148

R 2

a

 = 0.37

n = 36

y = 0.1668(x)

0.8469

R 2

a

 = 0.41

n = 25

EXPLANATION

regression equation

R 2

a

 = 0.41

n = 25

y = 0.1668(x)

0.8469

R 2

a

 = adjusted coefficient 

of determination

n = number of datasets

where: y = suspendedsediment concentration and 

x = daily mean streamflow

Data pair used in model

Best-fit regression model
Surface-Water Quality 13

accumulation was computed using the constituent measurements from both size fractions. The equation used for the 

mass-accumulation computation of the total trace-element 

concentration in suspended sediment collected during events is 

as follows:

Conctotal = [(ConcS x (%S/100) + (ConcF x (%F/100))] 

x SSC/100,000

where

Conctotal is the total trace-element concentration in 

suspended sediments, in milligrams per 

liter;

ConcS is the trace-element concentration in the sand 

fraction, in milligrams per kilogram;

%S is the percent of mass in total sample 

considered sand (particles greater than 

0.063 millimeters);

ConcF is the trace-element concentration in the fines 

fraction, in milligrams per kilogram;

%F is the percent of mass in total sample 

considered fines (particles less than 

0.063 millimeters);

SSC is suspended-sediment concentration of total 

sample, in milligrams per liter; and

100,000 is the conversion factor from milligrams per 

kilogram to milligrams per liter.

The mass accumulation computation used the sum of 

mass in each size fraction adjusted by the total SSC of the 

sample, then converted the trace-element concentration to 

milligrams per liter. When only one size fraction had enough 

mass for analyses, the trace-element concentration of the 

sample was still adjusted by the SSC, but should be assumed 

lower than the trace-element concentration that could be in the 

suspended sediments. An arithmetic average of trace-element 

concentrations were computed from all available suspendedsediment samples collected during the designated event 

duration. The event-based loads and yields were computed as 

previously described for the event-based suspended-sediment 

loads and yields in equations 5 and 6, using the arithmetic 

average of the trace element concentrations.

Surface-Water Quality

Many ancillary conditions such as land use, topography, 

atmospheric conditions, and streamflow conditions such as 

extreme base flow (droughts) and stormflows (floods) can 

affect the overall quality of a stream. The assessment of these 

conditions were used to determine the surface-water quality 

of Big River and to compute loads and yields of suspended 

sediment and the loads and yields of trace elements in the 

suspended sediments.

Streamflow Conditions

During the 2012 water year, Missouri’s precipitation 

was less than normal at 34.67 in. compared to the long-term 

(approximately 100 years) State average of 41.03 in. (National 

Oceanic and Atmospheric Administration, 2013). In October 

2011, about 40 percent of all Missouri counties had dry or 

drought conditions and about 60 percent were classified by 

the National Drought Mitigation Center (2013) as abnormally 

dry. From July through September 2012, all Missouri counties were experiencing at least moderate drought conditions. 

During August 2012, 35 percent of Missouri counties typically 

located in the northwest, southwest, and southeast corners of 

the State, were classified as having extreme drought conditions 

(National Drought Mitigation Center, University of NebraskaLincoln, 2013). Missouri’s precipitation for the 2013 water 

year was 43.58 in., which is above the long-term State average 

(National Oceanic and Atmospheric Administration, 2014b).

Precipitation gages were not available at the study 

sites; therefore, monthly precipitation was obtained from 

two NOAA climate stations within the study area at DeSoto 

and Dittmer, Mo. (National Oceanographic and Atmospheric 

Administration, 2015; fig. 5). The DeSoto climate station is 

located in the southern part of the study area near the upstream 

site. The Dittmer climate station is located in the northern 

part of the study area near the downstream site. During the 

study period, monthly precipitation at both climate stations 

ranged from approximately 1 in. (at Dittmer in July 2012) to 

more than 7 in. (at DeSoto in April 2013). Monthly precipitation was consistent between the two climate stations for most 

of the 2012 water year with the exception of higher monthly 

precipitation amounts at the Dittmer station during May, 

August, and September 2012 and higher monthly precipitation at the DeSoto Station during November 2011. September 

2012 had the highest monthly precipitation amounts for both 

climate stations during the 2012 water year. Monthly precipitation amounts increased during the 2013 water year, particularly from March through June, compared to the 2012 water 

year. Large differences in monthly precipitation between the 

climate stations were noted in January and July 2013, with the 

higher precipitation amounts recorded in the southern part of 

the study area at the DeSoto station. During the 2013 water 

year, April 2013 had the largest monthly precipitation amount 

recorded at the DeSoto station and March had the largest precipitation amount recorded at the Dittmer station.

The annual mean streamflow at the upstream site during the 2012 water year was approximately 189 ft3

/s with an 

annual runoff of 6.27 in. (table 4). Annual mean streamflow 

and annual runoff during the 2013 water year was nearly 

four times higher than during the 2012 water year at 695 ft3/s 

and 23.06 in., respectively (table 4). At the downstream site, 

the annual mean streamflow during the 2012 water year was 

419 ft3/s with an annual runoff of 6.22 in. The annual mean 

streamflow and annual runoff increased during the 2013 water 

year to 1,393 ft3/s and 20.63 in., respectively (table 4). 

(7)
14 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Streamflows were greatest in the spring months for 

the two study sites. At the upstream site, maximum daily 

streamflow was 2,390 ft3/s in March 2012 and 18,600 ft3/s in 

March 2013, and the minimum daily streamflow was 9.9 ft3/s 

in August 2012 and 42 ft3/s in September 2013 (table 4; 

fig. 6). Similar temporal variability also was measured at 

the downstream site. The maximum daily mean streamflow 

of 4,340 ft3/s was in March during water year 2012, and the 

maximum daily mean streamflow of 26,400 ft3/s was in April 

during the 2013 water year (table 4; fig. 6). The maximum 

peak streamflow during the study period was 21,900 ft3/s 

on April 19, 2013, at the upstream site, and the maximum 

peak streamflow during the study period was 28,700 ft3/s on 

April 20, 2013, at the downstream site. The historical maximum peak streamflow recorded at the downstream site was 

63,600 ft3/s on September 25, 1993 (table 4).

Continuous Water Quality

Water temperature is an important physical property 

because it can assist with quality control of monitor operations, such as detection of biological activity, extreme streamflow conditions, and human influences (Wilde, 2006). Water 

temperature is also a factor in determining a stream’s physical 

fluid properties because viscosity is a factor in determining 

sediment transport efficiency (Charlton, 2008). The maximum 

water temperature recorded at the upstream site was 32.7 °C 

on July 25, 2012, and the minimum recorded water temperature was -0.1 °C on January 3, 2013 (table 5). At the downstream site, the maximum water temperature recorded was 

30.9 °C on August 8, 2012, and the minimum recorded water 

temperature was 0.5 °C on January 3, 2013 (table 5). 

Figure 5. Total monthly precipitation at two National Oceanic and Atmospheric Administration climate stations near 

the Big River Basin, Missouri, October 2011–September 2013.

0

1

2

3

4

5

6

7

8

9

Oct. Nov. Dec. Jan Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan Feb. Mar. Apr. May June July Aug. Sept.

2012 2013

Total monthly precipitation, in inches

DeSoto, Missouri, climate station

Dittmer, Missouri, climate station

EXPLANATION

National Oceanic Atmospheric Administration, 2015

0 50 100 MILES

0 50 100 KILOMETERS

Big River Basin

2011
Surface-Water Quality 15

Table 4. Streamflow statistics for two study sites on the Big River, Missouri, October 2011–September 2013.

[ft3/s, cubic feet per second; ft, feet; in., inches]

Water 

year1

Maximum daily 

mean streamflow 

(ft3/s) and date

Minimum daily 

mean streamflow 

(ft3/s) and date

Maximum peak 

streamflow 

(ft3/s) and date

Maximum peak stage 

(ft) and date

Annual mean 

streamflow 

(ft3/s)

Annual 

runoff 

(in.)

Big River below Bonne Terre, Missouri (07017610; upstream site)

2012 2,390 March 17, 

2012

9.9 August 11, 

2012

4,810 March 16, 

2012

11.98 March 16, 

2012

2

189 26.27

2013 18,600 March 18, 

2013

42 September 14, 

2013

21,900 April 19, 

2013

26.54 April 19, 2013 695 23.06

Big River at Byrnesville, Missouri (07018500; downstream site)

2012 4,340 March 18, 

2012

52 July 28, 2012 4,920 March 18, 

2012

11.68 March 18, 

2012

419 6.22

2013 26,400 April 20, 

2013

115 September 

15–17, 

2013

28,700 April 20, 

2013

23.58 April 20, 2013 1,393 20.63

1922–2013 57,800 September 25, 

1993

25 August 30, 

1936

63,600 September 25, 

1993

29.37 September 25, 

1993

863 12.90

1

Water year is defined as the 12-month period beginning October 1 and ending September 30 of the calendar year in which it ends (water year 2012 is the 

period October 1, 2011 through September 30, 2012).

2

Computed with incomplete data because the streamgage was not in operation until October 13, 2011.

Figure 6. Daily mean streamflow computed during the study period at two study sites on the Big River, Missouri, 

October 2011–September 2013. Daily mean streamflow, in cubic feet per second

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr May June July Aug. Sept.

2012 2013

Big River at Byrnesville, Missouri 

(07018500; downstream site)

Big River below Bonne Terre, Missouri

(07017610; upstream site) 10

100

1,000

10,000

100,000

1

2011
16 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Water temperatures recorded at both sites followed 

similar diurnal variability and were similar at the two study 

sites. No water temperature data were corrected or missing for 

the upstream site during the study period. Water temperature 

data for the downstream site were unavailable from June 28 

to July 30, 2012, because stream levels were too low for the 

temperature sensor to be submerged for proper measurements. 

Extreme flood debris, such as organic materials, large limbs 

and trees, and trash, affected the water temperature measurements during two events in water year 2013, causing data to be 

removed from April 19 through 24, and August 21 through 23, 

2013 (fig. 7).

At the upstream site, daily mean turbidity ranged from 

1.4 to 520 FNU during the study period (table 5; fig. 8). The 

maximum value recorded during the study was 890 FNU on 

March 18, 2013, and the minimum value was 1.0 FNU on 

January 9 and 10, 2012 (table 5). Missing daily values at the 

upstream site were commonly caused by extreme biofouling 

during warmer months with lower streamflows and siltation 

of the instrument and its deployment pipe during high flows. 

Efforts were made to service and eliminate such effects but 

were not always successful. Other factors were instrumentation malfunctions and drift between calibrations. 

At the downstream site, turbidity measurements began 

on October 14, 2011. Daily mean turbidity ranged from 

1.3 to 240 FNU for the study period (table 5; fig. 8). The 

maximum value recorded during the study was 790 FNU on 

April 18, 2013, and the minimum value recorded was 0 FNU 

on October 15, 2012 (table 5). No data were removed during 

water year 2012; however, during the 2013 water year, many 

days were removed because of siltation of the monitor and 

deployment pipe during higher streamflows. It was noted during the 2013 water year that a large amount of trees and vegetation were removed and some construction on the property 

adjacent to the monitor deployment pipe had occurred. These 

events may have increased the monitor fouling issues during 

storm events because exposed soil was readily available during runoff from the lack of bank stabilization. Other periods of 

missing record were from instrumentation malfunction.

Turbidity showed a consistent temporal variability 

between both study sites (fig. 8). During storm events with 

precipitation evenly distributed throughout the basin and not 

localized, measured turbidity values at both sites showed 

similar but lagged changes with time as the runoff moved 

downstream. The travel time of a runoff peak was approximately 18 hours between sites. In some instances, a larger 

streamflow and greater turbidity values would be noted at the 

downstream site compared to the upstream site. It is possible 

that more localized storms in the downstream reaches of Big 

River caused an increase in streamflow. No streamgage exists 

on Mineral Fork to determine its contribution of streamflow 

and suspended sediment to the Big River. The low-head mill 

dam just upstream from the downstream site was observed to 

restrict streamflow during low-flow conditions and resulted in 

turbidity values that differed from those at the upstream site.

Table 5. Water-quality statistics for two study sites on the Big River, Missouri, October 2011–September 2013.

Water 

year1

Water temperature (degrees Celsius)

Maximum daily mean 

and date

Minimum daily mean 

and date

Maximum recorded 

and date

Minimum recorded 

and date

Big River below Bonne Terre, Missouri (07017610; upstream site)

2012 30.7 July 25, 2012 1.4 January 14, 2012 32.7 July 25, 2012 0.5 January 14, 2012

2013 30.1 July 19, 2013 0.6 January 3, 2013 30.1 July 18, 2013 -0.1 January 3, 2013

Big River at Byrnesville, Missouri (07018500; downstream site)

2012 30.0 August 8, 2012 1.5 January 14, 15, 2012 30.9 August 8, 2012 1.5 January 14, 15, 2012

2013 30.1 July 19, 2013 0.7 January 3, 2013 30.7 July 19, 2013 0.5 January 3, 2013

Water 

year1

Turbidity (formazin nephelometric units)

Maximum daily mean 

and date

Minimum daily mean 

and date

Maximum recorded 

and date

Minimum recorded 

and date

Big River below Bonne Terre, Missouri (07017610; upstream site)

2012 220 September 8, 2012 1.4 November 5, 2012 550 March 16, 2012 1 January 9, 10, 2012

2013 520 March 18, 2013 1.5 November 21, 24, 2013 890 March 18, 2013 1.2 November 20–22, 2013

Big River at Byrnesville, Missouri (07018500; downstream site)

2012 180 March 18, 2012 1.3 July 27, 2012 460 September 25, 2012 0.3 July 29, 2012

2013 240 March 20, 2013 1.6 January 3–5, 7, 8, 2013 790 April 18, 2013 0 October 15, 2012

1

Water year is defined as the 12-month period beginning October 1 and ending September 30 of the calendar year in which it ends (water year 2012 is the 

period October 1, 2011 through September 30, 2012).
Surface-Water Quality 17

Figure 7. Daily mean water temperature measured at two study sites on the Big River, Missouri, 

October 2011–September 2013.

0

5

10

15

20

25

30

35

0

5

10

15

20

25

30

35

Daily mean water temperature, in degrees Celsius

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2012 2013

Gaps indicate periods in 

which no data are available

2011

Periods of missing data (gaps) are due to equipment issues, 

no-flow conditions, extreme fouling, or exceedance of 

correction criteria, in which case data are deleted.
18 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13 Daily mean turbidity, in formazin nephelometric units

1

10

100

1,000

1

10

100

1,000

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2012 2013

Gaps indicate periods in 

which no data are available

Gaps indicate periods in 

which no data are available

Gaps indicate periods in 

which no data are available

2011

Periods of missing data (gaps) are due to equipment issues, 

no-flow conditions, extreme fouling, or exceedance of 

correction criteria, in which case data are deleted.

Periods of missing data (gaps) are due to equipment issues, 

no-flow conditions, extreme fouling, or exceedance of 

correction criteria, in which case data are deleted.

Figure 8. Daily mean turbidity measured at two study sites on the Big River, Missouri, October 2011–September 2013.
Suspended-Sediment Quantity 19

Suspended-Sediment Quantity

Discrete suspended-sediment concentrations were collected at each site at least monthly and during stormflow 

events (fig. 9). Samples were collected for the computation of 

daily SSC and SSL and were used to calibrate the regression 

model with the continuous turbidity data. During the 2012 

water year, 11 individual base-flow and 4 sets of event SSC 

samples were collected at both sites (table 6); however, the 

November 2011 event collected at the downstream site did not 

have enough sediment mass for trace-element analyses and 

was not used for any event-based computations. During the 

2013 water year, 7 individual base-flow and 3 sets of event 

SSC samples were collected at both sites (table 6). Base-flow 

SSC values ranged from 1 to 74 milligrams per liter (mg/L) 

at the upstream site during the study period, and event SSC 

values ranged from 74 to 1,091 mg/L (table 6; fig. 9). At the 

downstream site, base-flow SSC ranged from 4 to 127 mg/L 

and event SSC ranged from 27 to 871 mg/L (table 6; fig. 9). 

A previous study within the Ozark Plateaus (Davis and Bell, 

1998) determined that median base-flow SSC ranged from 

3 to 28 mg/L in streams of similar basin size and physiography, with increased SSC during increased streamflow. The 

median base-flow SSC for the upstream and downstream site 

during the study period was 10 mg/L and 13 mg/L, respectively (table 6).

Figure 9. Continuous streamflow and discrete suspended-sediment concentration samples collected at two study sites on 

the Big River, Missouri, October 2011–September 2013.

1

10

100

1,000

10

100

1,000

10,000

100,000

Daily mean streamflow

Suspended-sediment sample 

Daily mean streamflow, in cubic feet per second 

Suspended-sediment concentration, in milligrams per liter

10

100

1,000

10,000

100,000

1

10

100

1,000

10,000

1

0.1

10,000

Daily mean streamflow

Suspended-sediment sample 

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2011 2012 2013
20 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Table 6. Concentrations and size distributions of suspended-sediment samples collected at two study sites on 

the Big River, Missouri, October 2011–September 2013.

[g, gram; mg/L, milligram per liter; %, percent; <, less than; mm, millimeter; --, not measured]

Sample date and 

time Hydrologic event Total sample dry mass (g)

Suspended-sediment 

concentration (mg/L)

Suspended sediment

(% <0.063 mm)

Big River below Bonne Terre, Missouri (07017610; upstream site)

10/12/2011 16:40 base flow 0.005 4 --

11/10/2011 12:15 base flow 0.003 2 --

12/05/2011 18:00 base flow 0.052 20 --

12/15/2011 11:15 rise 0.530 220 93.8

12/15/2011 11:40 rise 0.707 228 87.8

12/15/2011 12:20 peak 0.596 178 94.9

12/15/2011 13:50 peak 0.489 151 98.0

12/15/2011 14:00 fall 0.478 183 97.8

12/15/2011 15:00 fall 0.454 153 96.2

01/10/2012 13:50 base flow 0.002 1 --

02/04/2012 16:45 base flow 0.328 74 --

03/15/2012 11:15 base flow 0.010 6 --

03/16/2012 10:50 rise 1.408 300 89.0

03/16/2012 15:15 rise 0.660 178 90.1

03/17/2012 00:01 peak 4.382 572 75.8

03/17/2012 16:40 fall 1.092 129 85.7

04/04/2012 16:15 base flow 0.012 10 --

04/16/2012 06:30 rise 0.939 153 95.6

04/16/2012 10:40 peak 0.764 201 95.5

04/17/2012 13:50 fall 0.641 312 98.3

05/21/2012 16:30 base flow 0.012 10 --

06/26/2012 12:45 base flow 0.008 10 --

07/31/2012 10:35 base flow 0.004 7 --

08/21/2012 15:30 base flow 0.005 7 --

09/08/2012 14:15 rise 2.352 541 77.5

09/08/2012 16:40 peak 2.075 450 75.1

09/10/2012 13:00 fall 0.175 74 97.1

10/16/2012 11:30 base flow 0.052 26 --

11/19/2012 12:00 base flow 0.005 4 --

12/17/2012 12:15 base flow 0.002 2 --

01/30/2013 11:20 rise 3.802 572 92.0

03/18/2013 11:30 peak 3.080 268 96.6

03/18/2013 15:50 peak 3.342 379 96.6

04/18/2013 13:32 rise 4.703 1,091 89.0

04/19/2013 09:14 peak 1.300 289 94.4

04/19/2013 11:24 fall 0.801 228 92.6

05/06/2013 14:30 base flow 0.238 57 --

06/26/2013 15:30 base flow 0.024 12 --

07/16/2013 10:40 base flow 0.021 23 --

08/28/2013 11:00 base flow 0.022 13 --

minimum base flow 1 --

maximum base flow 74 --

median base flow 10 --

minimum stormflow 74 75.1

maximum stormflow 1091 98.3

median stormflow 228 94.1
Suspended-Sediment Quantity 21

Sample date and 

time Hydrologic event Total sample dry mass (g)

Suspended-sediment 

concentration (mg/L)

Suspended sediment

(% <0.063 mm)

Big River at Byrnesville, Missouri (07018500; downstream site)

10/13/2011 15:00 base flow 0.067 21 --

11/10/2011 15:00 base flow 0.238 127 --

11/22/2011 13:00 rise 0.106 34 --

11/22/2011 13:30 rise 0.084 29 --

11/22/2011 13:50 peak 0.078 27 --

12/05/2011 12:40 base flow 0.047 17 --

02/28/2012 10:15 base flow 0.018 6 --

03/15/2012 15:10 base flow 0.035 17 --

03/17/2012 12:40 rise 1.330 392 92.6

03/17/2012 20:45 peak 2.722 408 95.0

03/18/2012 13:20 fall 1.732 260 94.1

04/04/2012 12:50 base flow 0.029 14 --

04/17/2012 10:25 peak 0.889 306 98.0

05/21/2012 13:37 base flow 0.033 19 --

06/26/2012 15:00 base flow 0.010 9 --

06/26/2012 15:05 base flow 0.009 10 --

07/31/2012 13:45 base flow 0.005 6 --

08/21/2012 10:10 base flow 0.008 9 --

09/10/2012 10:15 fall 0.326 103 94.3

10/16/2012 08:50 base flow 0.023 12

11/30/2012 10:00 base flow 0.005 4 --

12/17/2012 13:45 base flow 0.004 4 --

01/30/2013 16:45 rise 4.659 700 93.2

01/31/2013 08:30 rise 3.308 438 93.4

03/19/2013 18:00 peak 2.958 432 58.6

04/18/2013 16:03 rise 4.194 871 90.3

04/20/2013 16:15 peak 1.445 174 98.1

05/28/2013 09:30 base flow 0.126 44 --

06/26/2013 11:30 base flow 0.029 11 --

07/16/2013 12:00 base flow 0.039 25 --

08/28/2013 13:40 base flow 0.044 23 --

minimum base flow 4 --

maximum base flow 127 --

median base flow 13 --

minimum stormflow 27 58.6

maximum stormflow 871 98.1

median stormflow 306 93.7

Table 6. Concentrations and size distributions of suspended-sediment samples collected at two study sites on 

the Big River, Missouri, October 2011–September 2013.—Continued

[g, gram; mg/L, milligram per liter; %, percent; <, less than; mm, millimeter; --, not measured]
22 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Daily Suspended-Sediment Concentrations and 

Loads

The upstream and downstream sites had similar SSC and 

SSL extremes during the study, but these extremes did not 

always occur during the same stormflow events (figs. 10, 11). 

During the 2012 water year, the maximum daily mean SSC 

of 617 mg/L and maximum daily mean SSL of 2,920 tons at 

the upstream site occurred on September 8, 2012, whereas the 

maximum daily mean SSC of 522 mg/L and SSL of 6,120 tons 

at the downstream site occurred on March 18, 2012 (table 7). 

The maximum daily streamflow as shown in table 4 for the 

upstream site did not occur on the same event as the maximum 

daily mean SSC during the 2012 water year, but did occur on 

the same event during the 2013 water year (fig. 10). One possible explanation is that even though the streamflow was less 

than the water year maximum during the event on September 8, 2012, the amount of available suspended sediments in 

the system and the time between large events were greater, 

resulting in higher turbidity measurements and SSC results for 

that event. During the 2013 water year, the maximum daily 

mean SSC and streamflows both occurred on the March 18, 

2013, event at the upstream site (tables 4, 7). Maximum daily 

mean SSC and streamflows occurred on the same events during both study years for the downstream site (table 4, 7). 

Figure 10. Daily mean suspended-sediment concentrations computed at two study sites on the Big River, 

Missouri, October 2011–September 2013. Daily mean suspended-sediment concentration, in milligrams per liter

1

10

100

1,000

1

10

100

1,000

10,000

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2011 2012 2013
Suspended-Sediment Quantity 23

Annual SSLs were computed to estimate the total amount 

of suspended sediments that passed the sites for each water 

year. The annual SSL increased greatly during the study 

period because the first water year (2012) was classified as a 

drought year whereas more precipitation was recorded during 

the 2013 water year. The upstream site had an annual SSL of 

10,035 tons during the 2012 water year, which increased to 

191,294 tons for the 2013 water year, and the downstream site 

had an annual SSL of 21,612 tons in 2012, which increased to 

333,717 tons for the 2013 water year (table 7). 

A previous study along the Black River in southeast 

Missouri (Barr, 2009) also computed annual SSL for an Ozark 

stream to assess damage from an upstream reservoir embankment breach. The study site, Black River below Annapolis, 

Mo. (USGS site number 07061600), has a drainage area of 

493 mi2, which is similar to the drainage area of the Big River 

upstream site (409 mi2). The total annual SSL at the Black 

River site was 29,300 tons during the 2006 water year when 

sediment sources were readily available, but decreased to 

17,400 tons during the 2007 water year because the readily 

available suspended sediments had been transported through 

the basin. The short-term effects of the damaged reservoir still 

did not cause large sediment volumes in comparison to the 

historical mining effects within the Old Lead Belt. 

Figure 11. Daily mean suspended-sediment loads computed at two study sites on the Big River, Missouri, October 

2011–September 2013.

0.1

1

10

100

1,000

10,000

100,000

0.1

1

10

100

1,000

10,000

100,000

Daily mean suspended-sediment load, in tons

Big River at Byrnesville, Missouri (07018500; downstream site)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

2011 2012 2013
24 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Event-Based Suspended-Sediment 

Concentrations, Load, and Yields

For all stormflow events sampled during the study period, 

an event-based average SSC and SSL were computed to help 

determine the mass of suspended sediments transported during each sampled event. Averaged event SSCs ranged from 

approximately 100 mg/L to 1,400 mg/L at both study sites 

(table 8). Event SSLs ranged from about 180 to 32,000 tons 

at the upstream site and from about 390 to 53,000 tons at 

the downstream site (table 8). Most events lasted more than 

24 hours, and the same hydrologic event was sampled at both 

sites, except the December 15, 2011, event, when only the 

upstream site was sampled (table 8). The December 2011 

event was more localized in the upper portion of the watershed 

resulting in only a minor event by the time the event reached 

the downstream site. Event-specific SSLs were greater at the 

downstream site except for the September 2012 event, and 

event yields were greater at the upstream site than the downstream site during all events except April 2012 (table 8). Event 

loads and yields were greater during water year 2013 events, 

with the April 2013 event having the greatest loads and yields 

at both sites (table 8). It is possible that the large differences 

in event yields between sites are because of limited SSC collections during events at the downstream site, and because 

more sediments are available in the upper part of the basin 

closer to the historical mining activity. It should be noted that 

events differed in intensity and duration between the study 

sites, such as April 2012 (40 hours at the upstream site and 

63 hours at the downstream site), which could cause some bias 

in comparisons. Events at the downstream site were very slow 

moving and occurred over multiple days, but turbidity values 

did not show much variation at times, which made predictions 

of an event with sufficient, available suspended sediments difficult to determine. All event-based concentrations, loads, and 

yields are most likely biased low because of limited number 

of samples collected during the event but can be useful in 

approximating the minimum volume of suspended sediments 

transported downstream during stormflow events. 

Even though a limited number of events could be sampled, using the continuous turbidity data to compute the daily 

SSL in conjunction with event sampling provided adequate 

data to determine the majority of the SSL in Big River occurs 

during stormflow events. Not all stormflow events that 

occurred during the study period could be sampled, yet the 

events that were sampled make up a considerable portion of 

the annual SSL. Because the SSCs collected during base-flow 

conditions during the study period are generally very low 

(typically less than 50 mg/L at both sites), a general base-flow 

SSL can be computed for each site to compare to event-based 

SSLs. The median of all daily median streamflow values for 

the upstream site during the study period (132 ft3/s) was used 

to represent a base streamflow condition. Using the median 

streamflow and a SSC of 50 mg/L, an annual base-flow SSL 

for the study period can be derived as 18 tons, and the total 

SSL of the seven events sampled at the upstream site during 

the study period is about 57,700 tons (table 8). When compared to the sum of annual SSLs computed from the regression model for the study period (table 7), the base-flow SSL 

accounts for less than 0.01 percent and the sampled events 

account for about 29 percent of the total SSL at the upstream 

site. For the downstream site, the base streamflow computed 

Table 7. Daily suspended-sediment concentration and load statistics at two study sites on the Big River, Missouri, 

October 2011–September 2013.

[mg/L, milligram per liter; E, estimated]

Water 

year1

Maximum daily mean 

suspended-sediment 

concentration (mg/L) and 

date

Minimum daily mean 

suspended-sediment 

concentration (mg/L) 

and date(s)

Maximum daily mean 

suspended-sediment 

load (tons) and date

Minimum daily mean 

suspended-sediment 

load (tons) and date

Annual 

suspendedsediment 

load (tons)

Number of 

estimated 

days

Big River below Bonne Terre, Missouri (07017610; upstream site)

2012 617 September 8, 

2012

2 many days 2,920 September 8, 

2012

E 0.134 August 11, 

2012

10,035 59

2013 E 1,010 March 18, 2013 E 3 August 11, 2013 E 50,500 March 18, 

2013

0.526 December 

9, 2012

191,294 73

Big River at Byrnesville, Missouri (07018500; downstream site)

2012 522 March 18, 2012 2 July 27–29, 2012 6,120 March 18, 

2012

0.281 July 28, 

2012

21,612 0

2013 E 927 April 20, 2013 3 December 22, 

30, 31, 2012, 

January 1–9, 

2013

E 66,000 April 20, 2013 1.77 January 8, 

2013

333,717 62

1

Water year is defined as the 12-month period beginning October 1 and ending September 30 of the calendar year in which it ends (water year 2012 is the 

period October 1, 2011 through September 30, 2012).
Suspended-Sediment Quality 25

for the study period was 339 ft3/s. Using the same base-flow 

SSC of 50 mg/L, the annual base-flow SSLs were 46 tons 

during the study period, accounting for about 0.01 percent of 

the total SSL computed from the regression model (table 7). 

The six events sampled at the downstream site had a combined 

SSL of about 103,000 tons (table 8), or about 29 percent of the 

total SSL for the study period. 

Suspended-Sediment Quality

Suspended sediments collected during event sampling 

were more abundant in the fines fraction (tables 6 and 9). The 

supply of materials finer than bed material that are in suspension (also known as the “wash load”) usually have a greater 

effect on the SSC than streamflow conditions, because the 

rate of supply varies during and between events as well as 

from seasonal precipitation and vegetation (Charlton, 2008). 

Increases in streamflow produce increased SSC as erosion 

increases, releasing finer particles from storage and increasing the stream’s capacity for sediment transport. The event 

samples collected at the upstream site were 75 to 98 percent 

fines and the event samples collected at the downstream site 

were from 90 to 98 percent fines in all samples except one 

(table 6). Only one sample during the entire study, collected at 

the downstream site on the peak of the March 19, 2013, event, 

was less than 75 percent (59 percent) fines (table 6). 

Selected Trace-Element Concentrations in 

Suspended Sediments

 The laboratory results of event samples with adequate 

sample mass for analysis are listed in table 9 and include four 

selected trace-element concentrations—barium, cadmium, 

lead, and zinc. The four trace elements were selected for inclusion in this report because they are contained in ore minerals 

mined in the Big River Basin and are readily available for 

transport from both natural-source erosion and from mine 

waste. In addition, cadmium, lead, and zinc are considered 

toxic to aquatic life at certain concentrations in bed sediments 

and in dissolved form (MacDonald and others, 2000). The 

primary minerals containing barium, cadmium, lead, and zinc 

are relatively insoluble and predominately are found in the 

solid phase (Smith and Schumacher, 1991; 1993). No samples 

for dissolved trace-element concentrations were collected 

during the study period to include in the total concentration 

computation of trace elements at the study sites. Smith and 

Schumacher (1991; 1993) collected dissolved trace element 

concentrations at a site along the Big River near Desloge 

Table 8. Suspended-sediment concentrations, loads, and yields from sampled stormflow events at two study sites on the Big River, 

Missouri, October 2011–September 2013.

[hr, hour; ft3, cubic foot; mg/L, milligram per liter; lb, pound; mi2, square mile; (lb/mi2)/hr, pound per square mile per hour]

Event date Event duration 

(hr)

Event 

number

Sampled runoff 

volume 

(ft3)

Suspended-sediment

Average event 

concentration 

(mg/L)

Load Yield 

(lb/mi2)/hr

(lb) (ton)

Big River below Bonne Terre, Missouri (07017610; upstream site)

Dec. 15, 2011 19 1 50,150,000 1,110 354,000 177 522

Mar. 16–17, 2012 39.75 2 343,000,000 1,180 7,000,000 3,330 1,540

Apr. 16, 2012 23.75 3 49,110,000 354 352,000 176 125

Sept. 8–9, 2012 42.50 4 226,000,000 991 4,000,000 1,840 1,240

Jan. 29–31, 2013 38.75 5 740,000,000 572 13,200,000 6,590 1,670

Mar. 17–19, 2013 54 6 2,000,000,000 647 26,600,000 13,300 5,490

Apr. 18–19, 2013 51 7 2,210,000,000 1,380 64,600,000 32,300 9,510

Big River at Byrnesville, Missouri (07018500; downstream site)

Mar. 17–18, 2012 39.75 1 474,000,000 1,060 8,600,000 4,300 801

Apr. 15–18, 2012 63 2 510,000,000 306 4,900,000 2,430 161

Sept. 9–10, 2012 39.50 3 244,000,000 103 781,000 391 47.8

Jan. 30–31, 2013 35.50 4 759,000,000 919 23,200,000 11,600 1,520

Mar. 17–20, 2013 76.75 5 4,600,000,000 432 62,400,000 31,200 1,840

Apr. 18–20, 2013 53.50 6 3,300,000,000 958 110,000,000 53,100 2,920
26 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Table 9. Selected trace-element concentrations for two particle size distributions of suspended sediments collected during stormflow 

events at two study sites on the Big River, Missouri, October 2011–September 2013.

[sand, sediment greater than 0.063 millimeters; fines, sediment less than 0.063 millimeters; mg/kg, milligram per kilogram; --, not available]

Event 

number

Sample 

date

Sample 

time

Trace element concentrations in suspended sediments

Barium Cadmium Lead Zinc

Sand 

(mg/kg)

Fines 

(mg/kg)

Sand 

(mg/kg)

Fines 

(mg/kg)

Sand 

(mg/kg)

Fines 

(mg/kg)

Sand 

(mg/kg)

Fines 

(mg/kg)

Big River below Bonne Terre, Missouri (07017610; upstream site)

1 12/15/2011 11:15 -- 640 -- 10 -- 1,000 -- 1,000

12/15/2011 11:40 -- 670 -- 9 -- 900 -- 910

12/15/2011 12:20 -- 700 -- 9 -- 880 -- 900

12/15/2011 13:50 -- 700 -- 8 -- 750 -- 860

12/15/2011 14:00 -- 750 -- 7 -- 680 -- 780

12/15/2011 15:00 -- 730 -- 7 -- 680 -- 760

2 03/16/2012 10:50 -- 580 -- 10 -- 890 -- 780

03/16/2012 15:15 -- 580 -- 11 -- 1,100 -- 980

03/17/2012 00:01 240 600 8 16 750 1,700 470 1,000

03/17/2012 16:40 -- 550 -- 15 -- 1,700 -- 1,100

3 04/16/2012 06:30 -- 520 -- 12 -- 1,200 -- 1,100

04/16/2012 10:40 -- 520 -- 9 -- 750 -- 750

4 09/08/2012 14:15 280 540 30 35 1,400 2,400 1,200 1,800

09/08/2012 16:40 270 610 23 33 1,000 2,300 910 1,600

5 01/30/2013 11:20 340 660 12 10 1,000 980 620 670

6 03/18/2013 11:30 -- 560 -- 11 -- 1,300 -- 680

03/18/2013 15:50 -- 590 -- 12 -- 1,200 -- 620

7 04/18/2013 13:32 410 580 5 4 810 690 680 720

04/19/2013 09:14 -- 560 -- 14 -- 1,500 -- 790

Minimum 240 520 5 4 750 680 470 620

Median 280 590 12 10 1,000 1,000 680 860

Mean 308 613 16 13 992 1,189 776 937

Maximum 410 750 30 35 1,400 2,400 1,200 1,800

Big River at Byrnesville, Missouri (07018500; downstream site)

1 03/17/2012 12:40 -- 1,200 -- 4 -- 540 -- 290

03/17/2012 20:45 -- 1,200 -- 4 -- 960 -- 480

03/18/2012 13:20 -- 1,100 -- 6 -- 1,100 -- 570

2 04/17/2012 10:25 -- 1,500 -- 3 -- 790 -- 440

3 09/10/2012 10:15 -- 1,300 -- 7 -- 1,800 -- 760

4 01/30/2013 16:45 740 1,300 7 4 940 1,000 470 450

01/31/2013 08:30 -- 1,200 -- 5 -- 1,100 -- 500

5 03/19/2013 18:00 45 950 -- 8 53 1,600 31 590

6 04/18/2013 16:03 -- 740 -- 2 -- 360 -- 250

04/20/2013 16:15 -- 920 -- 8 -- 1,500 -- 680

Minimum 45 740 -- 2 53 360 31 250

Median -- 1,200 -- 5 -- 1,050 -- 490

Mean 393 1,141 7 5 497 1,075 251 501

Maximum 740 1,500 -- 8 940 1,800 470 760

Consensus-based sediment quality guidelines (MacDonald and others, 2000)

Cadmium (mg/kg) Lead (mg/kg) Zinc (mg/kg)

Consensus-based threshold effect concentration (TEC) 0.99

4.98

3

35.8

128

170

121

459

540

Consensus-based probable effect concentration (PEC)

Toxic effect threshold (TET)
Suspended-Sediment Quality 27

(fig. 1) during base flow and stormflow events, and total recoverable trace element concentrations only were collected during 

base flow conditions. The available dissolved trace element 

concentrations show the dissolved lead and zinc concentrations were very low, indicating a minimal portion of the total 

trace-element concentration would be from the dissolved 

phase. The full suites of trace element results for all samples 

are available on NWISWeb (http://nwis.waterdata.usgs.gov/

mo/nwis/qwdata).

Events 2, 4, 5, and 7 collected at the upstream site and 

events 4 and 5 collected at the downstream site had enough 

mass in both the sand and fines fractions for complete analyses 

of the total suspended sediments collected (table 9; fig. 12). 

Barium concentrations in the sand fraction were less than the 

concentrations in the fines fraction at both sites. Cadmium 

concentrations in sands were less than the fines fraction except 

for event number 5 at the upstream site (12 milligrams per 

kilogram [mg/kg] in sands, 10 mg/kg in fines) and event 4 

at the downstream site (7 mg/kg in sands, 4 mg/kg in fines), 

although the concentrations were similar (table 9). Events 5 

and 7 at the upstream site had similar but slightly higher concentrations of lead in the sand fraction than the fines fraction 

during event 5 and event 7 (table 9), and only event 4 at the 

downstream site had slightly higher but similar zinc concentrations in the sand fraction than the fine fraction (table 9). 

The greatest differences between sand and fines fraction 

concentrations were noted in lead and zinc concentrations for 

events 2 and 4 at the upstream site (fig. 12). The peak sample 

collected during event 2 on March 17, 2012, had lead concentrations of 750 mg/kg in the sand fraction and 1,700 mg/kg 

in the fines fraction, and zinc concentrations of 470 mg/kg 

in sand and 1,000 mg/kg in the fines (table 9, fig. 12). Event 

number 4 at the upstream site, collected September 8, 2012, 

had lead concentrations in the sand on the rising limb sample 

of 1,400 mg/kg and 2,400 mg/kg in the fines. The sand in the 

peak sample had a lead concentration of 1,000 mg/kg and the 

fines had a concentration of 2,300 mg/kg (table 9; fig. 12). 

The highest concentrations of cadmium (30 mg/kg in sand, 

35 mg/kg in fines) and zinc (1,200 mg/kg in sand, 1,800 mg/kg 

in fines) occurred during event number 4 at the upstream site. 

During a previous study of surface water and sediment 

quality in the Old Lead Belt, trace-element concentrations in 

suspended sediments also were measured during events within 

the Big River Basin (Smith and Schumacher, 1991; 1993), 

but do not indicate any changes in selected concentrations 

between study periods. Three event samples were collected 

between September 1988 and February 1989 at the Big River 

below Desloge, Mo. (USGS site number 07017620; site 6 

in Smith and Schumacher, 1993), located upstream from the 

study area for this report and downstream from the Desloge 

mine waste pile (fig. 1). Barium and cadmium concentrations 

at Desloge were similar to the upstream site concentrations 

and the lead and zinc concentrations at Desloge were higher 

than the upstream site concentrations. Barium concentrations in suspended sediments ranged from 390 to 630 mg/kg 

at Desloge and 240 to 750 mg/kg at the upstream site, and 

cadmium concentrations ranged from 21 to 30 mg/kg at 

Desloge and 4 to 35 mg/kg at the upstream site (table 9). Lead 

concentrations in the three event samples at Desloge during 

the previous study ranged from 1,100 to 3,200 mg/kg and at 

the upstream site the lead concentrations ranged from 680 

to 2,400 mg/kg. Zinc concentrations at Desloge ranged from 

1,100 to 2,200 mg/kg, which were higher than the upstream 

site concentrations (470 to 1,800 mg/kg). The difference in 

sampling location, event intensity, changes in geomorphology of the stream, or remediation efforts of mine waste piles 

could be reasons lead and zinc concentrations were higher at 

Desloge than the upstream site. Not enough data are available 

to determine if any long-term decreases have occurred. 

Sediment quality guidelines (SQG) for freshwater (MacDonald and others, 2000) describe two qualities of environmental effects from trace-element concentrations in suspended 

sediments—the threshold effect concentration (TEC) and the 

probable effect concentration (PEC). A TEC is defined as a 

concentration below which adverse effects are not expected to 

occur below, and a PEC is a concentration in which adverse 

effects are expected to occur at or above more often. Within 

these two sediment qualities are many levels and thresholds 

that help regulatory agencies assess the toxicity of sediments 

within a remediation study. The highest threshold in the PEC 

group is the toxic effect threshold (TET), which is the concentration above which sediment is considered to be heavily 

polluted causing adverse effects on sediment-dwelling organisms (MacDonald and others, 2000). Both TEC and PEC are 

consensus-based levels of concentration to reflect the intent 

of each SQG type. Although these threshold and probable 

effects are based on streambed sediments, comparisons were 

made with the stormflow event sediment results because these 

suspended sediments were most likely at rest on the streambed 

during base-flow conditions and after transport will be at rest 

again on the streambed. 

Concentrations of cadmium, lead, and zinc in suspended 

sediment samples collected during stormflow events at both 

sites exceeded the consensus-based TEC and consensus-based 

PEC (fig. 12). All cadmium concentrations in the fine and sand 

fractions of suspended sediments at both sites exceeded the 

consensus-based TEC (0.99 mg/kg) and PEC (4.98 mg/kg). 

All lead and zinc concentrations in the fine fraction of all suspended sediment from both sites greatly exceeded the consensus-based TEC (35.8 mg/kg for lead; 121 mg/kg for zinc) 

and the PEC (128 mg/kg for lead; 459 mg/kg for zinc). Lead 

concentrations in the fine fraction of all samples at both sites 

also exceeded TET of 170 mg/kg. Zinc concentrations in the 

fine fraction for four of the five samples from the upstream site 

also exceeded the TET of 540 mg/kg (fig. 12). Lead and zinc 

concentrations in the sand fraction exceeded their respective 

consensus-based PECs except for the sand fraction of event 

number 5 collected at the downstream site.

Concentrations of cadmium and zinc were notably 

higher in suspended sediment samples from the upstream 

site compared to the downstream site, especially in the fine 

fraction. The smaller cadmium and zinc concentrations at 
28 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

the downstream site could be a result of a decrease in source 

material enriched in these trace elements in the downstream 

areas of the watershed compared to the upstream area within 

the Old Lead Belt. Concentrations of lead, while variable, 

tended to be similar in both fractions at the two sites (fig. 12). 

The lead concentrations greatly exceeded the PEC as well 

as the TET, in some samples by a factor of 10, which indicates that lead-rich suspended sediments, especially in the 

fine fraction, are readily available for transport within the 

Big River Basin. These lead-enriched, finer sediments could 

remain in the system from historical mining, and as the capping of mine waste piles upstream from Bonne Terre continues 

to reduce additional sediment loadings, these fine sediments 

may be continually released as the river scours the streambed 

and erodes the stream banks causing lead-rich suspended sediment to remain in a state of equilibrium. 

Figure 12. Trace-element concentrations in two suspended-sediment size fractions collected during stormflow events at 

two study sites on the Big River, Missouri, October 2011–September 2013. Milligrams per kilogram 

0

200

400

800

1,000

1,200

1,400

1,600

600

Barium Cadmium

0

5

10

15

20

25

30

35

40

Lead Zinc

0

200

400

800

1,000

1,200

1,400

1,600

600

1,800

2,000

0

500

1,000

1,500

2,000

2,500

3,000

1 2 3 4 5 6 7 1 2 3 4 5 6

Event number (table 9)

1 2 3 4 5 6 7 1 2 3 4 5 6

1 2 3 4 5 6 7 1 2 3 4 5 6 1 2 3 4 5 6 7 1 2 3 4 5 6

EXPLANATION

Event number

Upstream site Downstream site Upstream site Downstream site

Upstream site

Downstream site

Upstream site Downstream site

Upstream site

Downstream site

Suspended-sediment fraction less than 0.063 millimeter (fines)

Suspended-sediment fraction greater than 0.063 millimeter (sands)

Consensus-based toxic effect threshold (TET; MacDonald and others, 2000)

Consensus-based probable effect concentration level (PEC; MacDonald and others, 2000)

Consensus-based threshold effect concentration level (TEC; MacDonald and others, 2000)

Big River below Bonne Terre, Missouri (07017610)

Big River at Byrnesville, Missouri (07018500)

Numeric representation of stormflow events collected at each site during study period (table 9)
Suspended-Sediment Quality 29

Variation within the event sample concentrations was typically low, but some large variations were noted for cadmium, 

lead, and zinc during two events. Event 7 at the upstream site, 

collected April 18 and 19, 2013, showed high variation of 

cadmium and lead concentrations in the fines fraction of the 

samples (table 9). The two samples collected during this event 

were collected near two different streamflow peaks; the first 

sample occurred from localized runoff of a smaller tributary 

upstream from the site (categorized as a rise sample in table 6) 

and the second sample occurred from the main channel peak, 

which traveled from farther upstream (considered the actual 

peak for the event in table 6). The increase in cadmium and 

lead during the second sample could be because of more 

sources of these trace elements from upstream sources. During 

this same event, high variation among concentrations at the 

downstream site also were noted. The event sampling at the 

downstream site (event 6) occurred on the rise and near the 

peak of the event, during April 18 and 20, 2013. This particular stormflow event caused flooding conditions at the routine 

sampling site as the river crested, which made the normal 

sampling location inaccessible. The peak sample collection 

was performed approximately one-half mile downstream. This 

alternate location experienced overbank backflow conditions 

along the row crop and sod fields, which may account for the 

large increases in concentrations of selected trace elements 

(fig. 12). 

Barium concentrations were nearly twice as high in 

event samples collected at the downstream site as compared 

to samples from the upstream site (fig. 12). It is probable the 

source of barium in the Big River comes from the Mineral 

Fork and Mill Creek, which flow through the historic, open-pit 

barite (barium sulfate, also known as tiff) mining district in 

Washington County. Mineral Fork is the largest tributary to the 

Big River between the two study sites. 

In the case where both size fractions could be analyzed 

for trace-element concentrations, a total trace-element concentration was computed for the SSC sample. Concentrations 

of total trace elements (the computed total of concentrations 

from both the sand and fine fractions) in suspended sediments 

varied by site and event (table 10). Concentrations are likely 

affected by stream velocity, localized runoff, seasonality, 

and event duration and intensity. The maximum and minimum concentrations at both sites for total barium, cadmium, 

lead, and zinc occurred during different events and in some 

instances, the maximum concentration for the upstream site 

was the same event for which a minimum concentration was 

detected at the downstream site (table 10). The maximum 

barium concentration at the upstream site was 0.613 mg/L 

during event 7, whereas the barium concentration at the 

downstream site during the same event (event number 6 for 

the downstream site) was the second-smallest concentration 

detected at 0.157 mg/L. The maximum lead concentration 

of 1.18 mg/L (the largest concentration detected during the 

study for both sites) occurred during event 4 (September 

2012) at the upstream site; however, the minimum lead 

concentration detected at the downstream site during this 

same event on September 10, 2012 (downstream site event 3) 

was 0.174 mg/L. The difference in concentrations between 

the two sites during the same stormflow event could be the 

effect of limited sample collection on the stormflow hydrographs, as well as more localized runoff in the headwaters of 

Big River. It is also possible that increased streamflow from 

Mineral Fork during the event diluted concentrations as the 

flows moved downstream. The maximum zinc concentration 

at the upstream site was the largest zinc concentration detected 

during the study for both sites at 0.901 mg/L, which occurred 

during event 4. The lowest concentration of both sites during the study period was 0.074 mg/L and was detected during 

event 3 at the downstream site. The maximum concentrations 

of barium, cadmium, lead, and zinc at the downstream site all 

occurred during event number 4 (January 2013).

The mean total trace-element concentrations in suspended 

sediments from stormflow events were compared between 

both sites during the study period. Mean concentrations of 

cadmium and lead were similar for both sites with mean cadmium concentrations of 0.004 mg/L at the upstream site and 

0.002 mg/L at the downstream site, and mean lead concentrations of 0.379 mg/L at the upstream site and 0.335 mg/L at 

the downstream site (table 10). Mean barium concentrations 

were higher at the downstream site (0.411 mg/L) than at the 

upstream site (0.184 mg/L). As noted previously, it is probable 

that a large source of barium enters the Big River from the 

Mineral Fork and Mill Creek, which drain a historical, openpit barite mining region. The mean zinc concentrations in the 

suspended sediments were higher upstream in the Big River 

than downstream, with a mean concentration of 0.291 mg/L 

at the upstream site, and mean concentration of 0.162 mg/L at 

the downstream site (table 10).

Seasonal comparisons of event-based lead and zinc 

concentrations in suspended sediments also were used for 

analyses of sediment quality in the Big River, though the 

study period was not long enough to provide extensive data 

for comparisons. The seasonal comparison boxplots of SSC 

show that more event samples were collected in winter at the 

upstream site than at the downstream site (fig. 13). The large 

number of samples in winter at the upstream site is because 

the first event collected at the upstream site was a pilot sampling event to ensure proper and consistent methods could be 

used during stormflow events and to determine the volume of 

sample needed to have adequate mass for trace-element analyses. Spring was the most-sampled season at both sites during 

the study period, because stormflow events tend to occur in 

the wetter spring months. Median lead and zinc concentrations collected in spring were similar at both sites, whereas 

median concentrations of lead and zinc were greatest in fall 

at the upstream site and greatest in winter at the downstream 

site (fig. 13). It is possible that the median concentrations in 

the fall were greater at the upstream site because the fall event 

from September 2012 was the first seasonal event in several 

months and the large amount of precipitation in the area of 

the site caused an increase in runoff. The winter event at the 

downstream site occurred in January 2013, after the removal 
30 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Table 10. Streamflow, suspended-sediment concentrations and particle-size distributions, and selected total trace-element 

concentrations in suspended sediments collected during stormflow events at two study sites on the Big River, Missouri, 

October 2011–September 2013.

[ft3/s, cubic foot per second; mg/L, milligram per liter; %, percent; >, greater than; mm, millimeter; <, less than]

Event 

number Sample date Sample time

Streamflow 

(ft3/s)

Suspended sediment Total trace element concentration in suspended 

sediments (mg/L)

Concentration 

(mg/L)

Sand Fines

(% >0.063 Barium Cadmium Lead Zinc

mm)

(% <0.063 

mm)

Big River below Bonne Terre, Missouri (07017610; upstream site)

1 12/15/2011 11:15 1,000 220 6.2 93.8 10.132 10.002 10.206 10.206

12/15/2011 11:40 965 228 12.2 87.8 10.134 10.002 10.180 10.182

12/15/2011 12:20 928 178 5.1 94.9 10.119 10.002 10.149 10.152

12/15/2011 13:50 818 151 2.0 98.0 10.104 10.001 10.111 10.127

12/15/2011 14:00 798 183 2.2 97.8 10.134 10.001 10.122 10.140

12/15/2011 15:00 750 153 3.8 96.2 10.107 10.001 10.100 10.112

2 03/16/2012 10:50 1,350 300 11.0 89.0 10.155 10.003 10.237 10.208

03/16/2012 15:15 1,370 178 9.9 90.1 10.093 10.002 10.176 10.157

03/17/2012 00:01 4,730 572 24.2 75.8 20.293 20.008 20.841 20.498

03/17/2012 16:40 1,690 129 14.3 85.7 10.061 10.002 10.188 10.122

3 04/16/2012 06:30 547 153 4.4 95.6 10.076 10.002 10.176 10.161

04/16/2012 10:40 813 201 4.5 95.5 10.100 10.002 10.144 10.144

4 09/8/2012 14:15 2,890 541 22.5 77.5 20.261 20.018 21.18 20.901

09/8/2012 16:40 3,390 450 24.9 75.1 20.236 20.014 20.888 20.642

5 01/30/2013 11:20 6,470 572 8.0 92.0 20.363 20.006 20.561 20.381

6 03/18/2013 11:30 20,100 268 3.4 96.6 10.145 10.003 10.337 10.176

03/18/2013 15:50 18,600 379 3.4 96.6 10.216 10.004 10.440 10.227

7 04/18/2013 13:32 11,600 1,091 11.0 89.0 20.613 20.004 20.767 20.781

04/19/2013 09:14 21,900 289 5.6 94.4 10.153 10.004 10.409 10.216

Median 1,370 228 6.2 93.8 0.134 0.002 0.206 0.182

Mean 5,300 328 9.4 90.6 0.184 0.004 0.379 0.291

Big River at Byrnesville, Missouri (07018500; downstream site)

1 03/17/2012 12:40 1,760 392 7.4 92.6 10.436 10.001 10.196 10.105

03/17/2012 20:45 3,380 408 5.0 95.0 10.465 10.002 10.372 10.186

03/18/2012 13:20 4,330 260 5.9 94.1 10.269 10.001 10.269 10.140

2 04/17/2012 10:25 2,410 306 2.0 98.0 10.450 10.001 10.237 10.132

3 09/10/2012 10:15 1,490 103 5.7 94.3 10.126 10.001 10.174 10.074

4 01/30/2013 16:45 6,050 700 6.8 93.2 20.884 20.003 20.698 20.316

01/31/2013 08:30 10,800 438 6.6 93.4 10.490 10.002 10.449 10.204

5 03/19/2013 18:00 27,300 432 41.4 58.6 20.248 20.002 20.414 20.155

6 04/18/2013 16:03 7,930 871 9.7 90.3 10.582 10.002 10.283 10.197

04/20/2013 16:15 26,700 174 1.9 98.1 10.157 10.001 10.256 10.116

Median 5,190 400 6.3 93.7 0.443 0.002 0.276 0.147

Mean 9,215 408 9.3 90.7 0.411 0.002 0.335 0.162

1

Concentration computed from fines only.

2

Concentrations computed from both sands and fines.
Suspended-Sediment Quality 31

Figure 13. Seasonal comparison of stormflow-event suspended-sediment concentrations and mass-accumulation lead and 

zinc concentrations within suspended sediments for two study sites on the Big River, Missouri, October 2011–September 2013.

Winter Spring Summer Fall Winter Spring Summer Fall

Winter Spring Summer Fall Winter Spring Summer Fall

Big River at Byrnesville, Missouri 

(07018500; downstream site)

o

x

o

7 10 0 2 2 7 0 1

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0

x

x

x

o

o

o

0.8

0.6

0.4

0.2

0

1.0

Total zinc concentration in suspended sediment, 

in milligrams per liter

7 10 0 2 2 7 0 1

o

o

x

o

7 10

o

o

10

0 2 2 7 0 1

0

200

400

600

800

1,000

1,200

1,400

Suspended-sediment concentration, 

in milligrams per liter

EXPLANATION

Winter

Spring

Summer

Fall

Number of samples 

Upper adjacent

75th percentile

50th percentile

 (median)

25th percentile

Lower adjacent

Lower outside

Lower detached

Upper detached

Upper outside

December−February

March–May

June–August

September–November

Total lead concentration in suspended sediment, 

in milligrams per liter

Big River below Bonne Terre, 

Missouri (07017610; upstream site)

Winter Spring Summer Fall Winter Spring Summer Fall

Big River at Byrnesville, Missouri 

(07018500; downstream site)

Big River below Bonne Terre, 

Missouri (07017610; upstream site)

Interquartile

range

of vegetation from the banks near the streamgage location, 

which could have increased the available suspended sediments 

during runoff. No events were sampled during summer months 

within the study period. 

Event-Based Loads and Yields of Selected 

Trace-Element Concentrations in Suspended 

Sediments

Results of the four selected trace-element event-based 

average concentrations and the event-based load and yields 

are shown in table 11. Event-based loads computed at the 

upstream site were largest for all four constituents during 

April 2013 (event 7), with the lead load being the largest with 

29.4 tons transported during the event. There was minimal 

decrease in the corresponding lead load at the downstream 

site, where the event-based load was 27.1 tons. The largest 

event-based lead load for the downstream site was 29.9 tons 

during event 5 in March 2013.

An event-based yield also was computed to make the 

study sites more comparable by normalizing the drainage 

areas and event durations. Event-based yields were larger at 

the upstream site (table 11). Two events showed similar lead 

and zinc yields for both sites—April 2012 and January 2013. 

The largest event-based lead yield at the upstream site was 

8.17 pounds per square mile per hour during event 7. The 

downstream site had smaller yields, with the largest eventbased lead yield being 1.76 pounds per square mile per hour 

during event 5.
32 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Table 11. Selected trace element concentrations, loads, and yields in suspended sediments from sampled stormflow events at two 

study sites on the Big River, Missouri, October 2011–September 2013.

[hr, hour; mg/L, milligrams per liter; lb, pound; mi2, square mile; lb/mi2/hr, pounds per square mile per hour]

Event 

number Event date Event duration (hr)

Trace element in suspended sediments

Constituent

Average event 

concentration 

(mg/L)

Load Yield 

(lb/mi2/hr) (lb) (ton)

 Big River below Bonne Terre, Missouri (07017610; upstream site)

1 Dec. 15, 2011 19 Barium 0.677 164 0.082 0.322

Cadmium 0.009 2.88 0.001 0.004

Lead 0.869 284 0.142 0.412

Zinc 0.920 298 0.149 0.434

2 Mar. 16–17, 2012 39.75 Barium 0.602 3,395 1.70 0.789

Cadmium 0.014 88.3 0.04 0.020

Lead 0.942 5,944 2.97 1.10

Zinc 0.985 5,825 2.91 1.32

3 Apr. 16, 2012 23.75 Barium 0.176 175 0.088 0.062

Cadmium 0.003 3.31 0.002 0.001

Lead 0.319 295 0.147 0.111

Zinc 0.305 285 0.143 0.106

4 Sept. 8–9, 2012 42.50 Barium 0.497 1,885 0.943 0.620

Cadmium 0.032 116 0.058 0.040

Lead 2.07 7,512 3.76 2.58

Zinc 1.54 5,536 2.77 1.93

5 Jan. 29–31, 2013 38.75 Barium 0.363 8,355 4.18 1.06

Cadmium 0.006 134 0.067 0.017

Lead 0.561 12,930 6.46 1.64

Zinc 0.381 8,772 4.39 1.11

6 Mar. 17–19, 2013 54 Barium 0.361 14,776 7.39 3.06

Cadmium 0.007 295 0.148 0.061

Lead 0.776 32,180 16.09 6.59

Zinc 0.403 16,737 8.37 3.42

7 Apr. 18–19, 2013 51 Barium 0.765 35,655 17.83 5.27

Cadmium 0.008 437 0.218 0.058

Lead 1.18 58,846 29.42 8.17

Zinc 0.996 46,808 23.40 6.87

Annual total of 

sampled events

Water year1 2012

Barium -- 5,619 2.81 1.79

Cadmium -- 211 0.105 0.065

Lead -- 14,034 7.02 4.20

Zinc -- 11,945 5.97 3.79

Water year1 2013

Barium -- 58,785 29.39 9.39

Cadmium -- 866 0.433 0.136

Lead -- 103,956 51.98 16.39

Zinc -- 72,317 36.16 11.40
Suspended-Sediment Quality 33

Table 11. Selected trace element concentrations, loads, and yields in suspended sediments from sampled stormflow events at two 

study sites on the Big River, Missouri, October 2011–September 2013.—Continued

[hr, hour; mg/L, milligrams per liter; lb, pound; mi2, square mile; lb/mi2/hr, pounds per square mile per hour]

Event 

number Event date Event duration (hr)

Trace element in suspended sediments

Constituent

Average event 

concentration 

(mg/L)

Load Yield 

(lb/mi2/hr) (lb) (ton)

 Big River at Byrnesville, Missouri (07018500; downstream site)

1 Mar. 17–18, 2012 39.75 Barium 1.17 9,461 4.73 0.879

Cadmium 0.004 38 0.019 0.004

Lead 0.838 7,649 3.82 0.690

Zinc 0.431 3,905 1.95 0.354

2 Apr. 15–18, 2012 63 Barium 0.450 7,158 3.58 0.237

Cadmium 0.001 14.3 0.007 0.000

Lead 0.237 3,770 1.88 0.125

Zinc 0.132 2,100 1.05 0.070

3 Sept. 9–10, 2012 39.50 Barium 0.126 958 0.479 0.059

Cadmium 0.001 5.16 0.003 0.000

Lead 0.174 1,327 0.663 0.081

Zinc 0.074 560 0.280 0.034

4 Jan. 30–31, 2013 35.50 Barium 1.13 28,357 14.2 1.86

Cadmium 0.004 101 0.050 0.007

Lead 0.922 23,325 11.7 1.53

Zinc 0.418 10,580 5.29 0.695

5 Mar. 17–20, 2013 76.75 Barium 0.248 35,864 17.9 1.06

Cadmium 0.002 292 0.146 0.009

Lead 0.414 59,814 29.9 1.76

Zinc 0.155 22,352 11.2 0.659

6 Apr. 18–20, 2013 53.50 Barium 0.661 75,034 37.5 2.04

Cadmium 0.002 296 0.148 0.008

Lead 0.411 54,254 27.1 1.39

Zinc 0.255 31,576 15.8 0.830

Annual total of 

sampled events

Water year1 2012

Barium -- 17,577 8.79 1.18

Cadmium -- 57 0.029 0.004

Lead -- 12,745 6.37 0.90

Zinc -- 6,565 3.28 0.46

Water year1 2013

Barium -- 139,255 69.6 4.95

Cadmium -- 689 0.344 0.023

Lead -- 137,393 68.7 4.69

Zinc -- 64,509 32.3 2.18

1

Water year is defined as the 12-month period beginning October 1 and ending September 30. The water year is designated by the calendar year in which it 

ends and contains 9 of the 12 months.
34 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Loads computed during the study period for sampled 

events were higher at the downstream site and yields were 

higher at the upstream site. As previously noted, computed 

annual runoff was greater at the upstream site than the 

downstream site. In addition, stormflow events at the downstream site had much longer durations and lower velocities 

than events at the upstream site. It is possible that the lowhead dam just upstream from the sampling location at the 

downstream site slowed the stream velocity enough to cause 

sediments to fall out of suspension and be deposited on the 

streambed before reaching the sampling location. Other possible effects could be localized precipitation and fewer areas 

affected by mining activities in the downstream part of the 

Big River Basin. The additional volume of streamflow from 

Mineral Fork could dilute some trace-element concentrations 

downstream, though it is difficult to determine the amount 

of influence to the Big River because no streamgages are in 

operation on this tributary. The decreases in loads from the 

upstream to the downstream site also could be an artifact of 

the limited number of event samples that could be collected at 

the downstream site.

Total trace-element loads and yields in suspended sediments were computed from the sampled events for each year 

in the study. Although no trace-element concentrations were 

collected during base-flow conditions, SSCs during base-flow 

typically were less than 50 mg/L and the majority of suspended sediments are transported through the Big River during 

stormflow events. Given the affinity of trace elements to be 

transported with sediments (Horowitz and Elrick, 1987), it is 

likely that the majority of the selected trace elements in suspended sediments are transported during runoff events as well. 

Using these assumptions, a total event-based load and yield for 

barium, cadmium, lead, and zinc for the events sampled were 

calculated for each water year (table 11). The total load and 

yield should be considered an estimate and a minimum representation of the total trace-element loads because limited data 

were available for the computations and not all events during 

the study period were sampled or had sufficient material mass 

for analyses. 

All total loads and yields increased at each site for the 

four selected trace elements from the 2012 to the 2013 water 

years (table 11), most likely because of increased precipitation and runoff during the 2013 water year. The total barium 

load in suspended sediments was higher for sampled events 

collected at the downstream site during both study years, with 

the 2013 water year having the most substantial increase in 

total load from 29.4 tons at the upstream site to 69.6 tons at 

the downstream site. Cadmium load decreased during the 2012 

water year from 0.105 tons at the upstream site to 0.029 tons 

at the downstream site and decreased slightly downstream 

during the 2013 water year from 0.433 tons at the upstream 

site to 0.344 tons at the downstream site. Lead loads slightly 

decreased during the 2012 water year from 7.02 tons at the 

upstream site to 6.37 tons at the downstream site, and only 

slightly increased downstream during the 2013 water year 

from 52 tons at the upstream site to about 68.7 tons at the 

downstream site. Zinc loads were lower at the downstream site 

than the upstream site, although the decrease in total load was 

not substantial during either water year (table 11). Comparison 

of the total yield of the four selected trace elements based on 

all events in each water year showed a decrease in barium, 

cadmium, lead, and zinc yields from the upstream to downstream site, indicating readily-available sediment sources are 

closer to the upstream site (table 11). 

Seasonal comparisons of event-based loads and yields 

of lead and zinc concentrations in suspended sediments were 

similar between sites. The median loads and yields of lead and 

zinc were higher in spring at each site; however, the single 

winter event (event 4) at the downstream site had the highest 

median lead and zinc load during the study (fig. 14). Seasonal 

observation of the lead and zinc yields shows the single fall 

event (event 4) and the spring events at the upstream site have 

similar medians. Event-based loads and yields of lead and 

zinc in suspended sediments increased slightly from winter to 

spring at both sites and decreased greatly from spring to fall at 

the downstream site (fig. 14).
Suspended-Sediment Quality 35

Figure 14. Seasonal comparison of stormflow-event loads and yields of lead and zinc in suspended sediments at two study 

sites on the Big River, Missouri, October 2011–September 2013.

o

o

o

o

o

o

0.1

0.5

1

5

10

50

100

0.1

0.5

1

5

10

50

o

o

o

0.01

0.05

0.1

0.5

1

5

10

0.01

0.05

0.1

0.5

5

10

o

o

o

2 4 0 1 1 4 0 1 2 4 0 1 1 4 0 1

2 2 4 0 1 1 4 0 1 4 0 1 1 4 0 1

Event-based lead load in suspended sediments,

in tons

Event-based zinc load in suspended sediments,

in tons

Event-based lead yield in suspended sediments,

in pounds per square mile per hour

Event-based zinc yield in suspended sediments,

in pounds per square mile per hour

Winter Spring Summer Fall Winter Spring Summer Fall

Big River at Byrnesville, Missouri 

(07018500; downstream site)

x

x

Winter Spring Summer Fall Winter Spring Summer Fall Winter Spring Summer Fall Winter Spring Summer Fall

o

o

4

EXPLANATION

Summer

Fall

Number of samples 

Upper adjacent

75th percentile

50th percentile

 (median)

25th percentile

Lower adjacent

Lower outside

Lower detached

Upper detached

Upper outside

December−February

March–May

June–August

September–November

Big River below Bonne Terre, 

Missouri (07017610; upstream site)

Winter Spring Summer Fall Winter Spring Summer Fall

Big River at Byrnesville, Missouri 

(07018500; downstream site)

Big River below Bonne Terre, 

Missouri (07017610; upstream site)

Interquartile

range

Winter

Spring
36 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

Summary

Missouri was the leading producer of lead in the United 

States—as well as the world—for more than a century. One 

of the lead sources is known as the Old Lead Belt, located 

in southeast Missouri. The primary ore mineral in the region 

is galena, which can be found both in surface deposits and 

underground as deep as 200 feet. More than 8.5 million tons 

of lead were produced from the Old Lead Belt before operations ceased in 1972. Although active lead mining has ended, 

the effects of mining activities still remain in the form of large 

mine waste piles on the landscape typically near tributaries 

and the main stem of the Big River, which drains the Old Lead 

Belt. Six large mine waste piles, some spanning more than a 

mile in diameter, exist within the Big River Basin. For the past 

century, the piles have been sources of lead and zinc-rich sediments to be transported by natural fluvial processes and wind 

downstream into the Big River. The U.S. Environmental Protection Agency (EPA) Region 7 completed 4-year reclamation 

efforts to cap and prevent further erosion of the piles in 2012. 

A study was conducted by the U.S. Geological Survey 

in cooperation with EPA Region 7 to assess the amount and 

availability of suspended sediments and to assess the traceelement concentrations of suspended sediments transported 

through the Big River basin after reclamation of the mine 

waste piles. Streamflow and suspended sediments were quantified and sampled at two locations in the basin: Big River 

below Bonne Terre, Mo. (USGS site number 07017610; also 

referred to as the upstream site), located less than 5 miles 

downstream from the Old Lead Belt, and Big River near 

Byrnesville, Mo. (USGS site number 07018500; also referred 

to as the downstream site), located about 68 miles downstream 

from Bonne Terre. The Big River discharges into the Meramec 

River, which discharges into the Mississippi River, south of 

St. Louis, Mo.

Discrete suspended-sediment concentration (SSC) samples were used to develop a regression model with continuous turbidity measurements and (or) streamflow to compute 

time-series SSC and suspended-sediment load (SSL) values. 

Discrete SSC samples were paired with corresponding turbidity and streamflow measurements made at about the mean time 

of the SSC sample and plotted to identify outliers and trends. 

The SSC, SSL, and sediment yields were computed 

for hydrologic events when cross-sectional sampling and 

streamflow measurements were collected. Seven events were 

sampled at the upstream site and six events were sampled at 

the downstream site during the study period. 

Streamflows were greatest in the spring months and followed similar temporal variability at both sites. The maximum 

peak streamflow during the study period at the upstream site 

was 21,900 cubic feet per second (ft3/s) on April 19, 2013, 

and was 28,700 ft3/s on April 20, 2013 at the downstream 

site. Water temperature ranged from -0.1 to about 33 degrees 

Celsius (oC) at both sites. Turbidity ranged from 1.0 to 

890 formazin nephelometric units (FNU).

Base-flow SSC values ranged from 1 to 74 milligram 

per liter (mg/L) at the upstream site during the study period, 

and event SSC values ranged from 74 to 1,091 mg/L. At the 

downstream site, base-flow SSC ranged from 4 to 127 mg/L 

and event SSC ranged from 27 to 871 mg/L. The upstream and 

downstream sites had similar SSC and SSL extremes during 

the study, but these extremes did not occur during the same 

events. 

The annual SSL increased greatly during the study 

period, as the first water year (2012) was classified as a 

drought year and more precipitation was recorded during the 

2013 water year. The upstream site had an annual SSL of 

10,035 tons during the 2012 water year, and 191,294 tons for 

the 2013 water year. The downstream site had an annual SSL 

of 21,612 tons during the 2012 water year, and 333,717 tons 

for the 2013 water year. 

An event-based average SSC and SSL were computed 

to help determine the mass of sediments transported during 

each sampled event. Event SSCs ranged from approximately 

100 mg/L to 1,400 mg/L at both study sites and event SSLs 

ranged from about 180 to 32,000 tons at the upstream site, and 

from about 390 to 53,000 tons at the downstream site. Event 

SSLs were greatest at the downstream site. Event loads and 

yields were greater during water year 2013 events, with the 

April 2013 event having the greatest loads and yields at both 

sites.

Although a limited number of events could be sampled, 

using the continuous turbidity data to compute the daily SSL 

in conjunction with event sampling provided adequate data 

to determine the majority of the SSL in Big River occurs during stormflow events. Not all stormflow events that occurred 

during the study period could be sampled, yet the events that 

were sampled make up a considerable portion of the annual 

SSL. Discrete SSCs collected during base-flow conditions 

during the study period were generally very low (typically less 

than 50 mg/L). The base-flow average SSC was used with a 

median of daily median streamflow values to determine a base 

flow SSL. The base flow SSL at the upstream site was about 

18 tons, or less than 0.01 percent of the SSL computed by the 

regression model during the study period. The event-based 

SSL from the seven sampled events during the study period 

was about 57,700 tons, accounting for about 29 percent of the 

SSL at the upstream site. At the downstream site, the computed base flow SSL was about 46 tons for the study period, 

which accounts for about 0.01 percent of the SSL, and the SSL 

from the six sampled events was about 103,000 tons, accounting for about 29 percent of the SSL computed by the regression model during the study period. 

The total concentrations of barium, cadmium, lead, and 

zinc computed for each individual event sample were used to 

determine an event-based arithmetic average concentration 

to determine an event-based concentration, load (flux), and 
Summary 37

yield of each constituent. The arithmetic average trace-element 

concentrations were computed from all available samples 

during the designated event duration. For events with enough 

mass in both the sand and fines fraction for analysis, it was 

noted that nearly all sand fraction concentrations were less 

than the concentrations of the fines fraction for all four trace 

elements. Barium concentrations were nearly twice as high in 

event samples collected at the downstream site as compared to 

samples from the upstream site. The likely source of barium 

in the Big River is the Mineral Fork and Mill Creek, which 

flow through the historical barite (barium sulfate, also known 

as tiff) mining district in Washington County. Cadmium 

and zinc concentrations were nearly two times higher at the 

upstream site than at the downstream site, while lead concentrations appeared similar between both sites. It is possible 

the suspended sediments containing cadmium, lead, and zinc 

have decreased concentrations downstream because slower 

velocities cause the sediments to fall from suspension as they 

are transported downstream farther from their source. Traceelement concentrations in suspended sediment sampled during 

stormflow events during a previous study had higher concentrations of lead and zinc than concentrations measured in 

suspended sediments collected during events at the upstream 

site. Although the previous study concentrations were higher 

(1,100 to 3,200 milligram per kilogram [mg/kg] of lead; 1,100 

to 2,200 mg/kg of zinc) than those measured at the upstream 

site (680 to 1,400 mg/kg of lead; 470 to 1,200 mg/kg of zinc), 

there are no indications of long-term or substantial decreases 

as data are limited and could be affected by differences in 

sampling location, event intensity, changes in the geomorphology of the stream, or remediation efforts of mine waste piles.

Sediment quality guidelines for freshwater describe two 

qualities of environmental effects from trace-element concentrations in suspended sediments—the threshold effect concentration (TEC) and the probable effect concentration (PEC)—

and help regulatory agencies assess the toxicity of sediments 

within a remediation study. Concentrations of cadmium, lead, 

and zinc in suspended sediment samples collected during 

stormflow events at both sites exceeded the consensus-based 

TEC and consensus-based PEC. All lead and zinc concentrations in the fine fraction of all suspended sediment from both 

sites greatly exceeded the consensus-based TEC (35.8 mg/kg 

for lead; 121 mg/kg for zinc) and the PEC (128 mg/kg for 

lead; 459 mg/kg for zinc). Lead concentrations in the fine 

fraction of all samples at both sites also exceeded the toxic 

effect threshold (TET) of 170 mg/kg, above which sediment 

is considered to be heavily polluted causing adverse effects on 

sediment-dwelling organisms. Zinc concentrations in the fine 

fraction in four of five sampled events from the upstream site 

also exceeded the TET of 540 mg/kg.

Concentrations of cadmium and zinc were notably 

higher in suspended sediment samples from the upstream 

site compared to the downstream site, especially in the fine 

fraction. The smaller cadmium and zinc concentrations at 

the downstream site could be a result of a decrease in source 

material enriched in these trace elements in the downstream 

areas of the watershed compared to the upstream area within 

the Old Lead Belt. The lead concentrations greatly exceeded 

the PEC as well as the TET, in some samples by a factor of 10, 

which indicates that lead-rich suspended sediments, especially 

in the fine fraction, are readily available for transport within 

the Big River Basin. These lead-enriched, finer sediments 

could remain in the system from historical mining, and as 

the capping of mine waste piles upstream from Bonne Terre 

continues to reduce additional sediment loadings, these fine 

sediments may be continually released as the river scours the 

streambed and erodes the stream banks, causing lead-rich 

suspended sediment to remain in a state of equilibrium.

Event-based trace-element load and yields in suspended 

sediments also were used for analyses of sediment quality in 

the Big River. The total barium load in suspended sediments 

was higher for sampled events collected at the downstream 

site during both study years. Cadmium and zinc loads in suspended sediments were lower at the downstream site than the 

upstream site, although the decrease in total load was not substantial during the study period. Lead loads in suspended sediments were lower at the downstream site during the first study 

year, with a slightly higher load downstream in the second 

year though the increase from upstream to downstream was 

small. Event yields were higher at the upstream site. Storm 

events at the downstream site had much longer durations and 

lower velocities than events at the upstream site. All four trace 

element total loads and yields in suspended sediments computed from event samples increased at each site from the 2012 

to the 2013 water years, most likely because of increased precipitation and runoff during the 2013 water year. Total loads of 

barium, cadmium, and lead were higher at the downstream site 

than the upstream site during both water years. Comparison of 

the total yield of the four selected trace elements based on all 

events in each water year showed a decrease in barium, cadmium, lead, and zinc yields from the upstream to downstream 

site, indicating readily-available sediment sources are closer to 

the upstream site. 

 Median lead and zinc concentrations collected in spring 

were similar at both sites, whereas median concentrations of 

lead and zinc were greatest in fall at the upstream site and 

greatest in winter at the downstream site. It is possible that the 

median concentrations in the fall were greater at the upstream 

site because of one large event in September 2012. The winter 

event at the downstream site occurred in January 2013, after 

the removal of vegetation from the banks near the streamgage 

location, which could have increased the available suspended 

sediments during runoff. Seasonal comparison of event-based 

loads computed at the upstream site were largest for all four 

constituents during April 2013 (event 7), with the lead load 

being the largest with 29.4 tons transported during the event. 
38 Surface-Water Quality and Suspended-Sediment Quantity and Quality, Big River Basin, Southeastern Missouri, 2011–13

References Cited

Anderson, C.W., 2005, Turbidity (version 2.1): U.S. Geological Survey Techniques of Water-Resources Investigations, 

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For more information concerning this publication, contact: 

Director, Missouri Water Science Center 

U.S. Geological Survey 

1400 Independence Road, MS-100 

Rolla, MO 65401 

(573) 308-3667

Or visit the Missouri Water Science Center Web site at: 

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Barr—Surface-Water Quality and Suspended-Sediment Quantity and Quality within the Big River Basin, Southeastern Missouri, 2011–13—SIR 2015–5171

ISSN 2328-0328 (online)

http://dx.doi.org/10.3133/sir20155171