iii

CONTENTS

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

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

Purpose and scope .........................................................................................................................................................6

Previous studies .............................................................................................................................................................6

Methods of study....................................................................................................................................................................7

Limitations of data and methods of analysis .................................................................................................................9

Summary of sediment loads, yields, and discharge-weighted sediment concentrations......................................................10

River Input Monitoring station data, 1985–2001 ........................................................................................................10

Suspended-sediment data, 1952 through 1984 ............................................................................................................10

Suspended-sediment data, 1985 through 2001 ............................................................................................................10

Instantaneous suspended-sediment concentrations ..............................................................................................................35

Sediment-transport curves ...........................................................................................................................................35

Summary and conclusions....................................................................................................................................................57

References cited ...................................................................................................................................................................58

Figures

1. Map showing location of 65 stations in the Chesapeake Bay Watershed with at least 3 years of water

year suspended-sediment load record from 1952 through 2001.........................................................................2

2. Graph showing average annual water year suspended-sediment load computed at daily-load stations 

compared with loads computed with the Estimator program for water years 1973 through 1993.....................9

3. Chart showing listing of sediment stations in the Chesapeake Bay Watershed with at least 3 years of 

record from water years 1952 through 2001.....................................................................................................13

4. Graph showing distribution of drainage areas for 65 sediment stations in the Chesapeake Bay Watershed

with at least 3 years of sediment record from 1952 through 2001....................................................................14

5. Graph showing relation of (A) average annual suspended-sediment load to drainage area, (B) average 

annual suspended-sediment load to mean-daily discharge, (C) average annual sediment yield to

drainage area, and (D) average annual discharge-weighted sediment concentration to drainage

area for 65 sediment stations in the Chesapeake Bay Watershed with at least 3 years of record

from 1952 through 2001 ...................................................................................................................................14

6a–6c. Maps showing:

6a. Average annual suspended-sediment load from 1985 through 2001 for nine River Input

Monitoring (RIM) stations in the Chesapeake Bay Watershed..........................................................15

6b. Average annual sediment yield from 1985 through 2001 for nine River Input Monitoring 

(RIM) stations in the Chesapeake Bay Watershed .............................................................................16

6c. Average annual discharge-weighted sediment concentration from 1985 through 2001 for nine

River Input Monitoring (RIM) stations in the Chesapeake Bay Watershed.......................................17
iv

Figures—Continued

 7a–7c. Maps showing:

7a. Average annual suspended-sediment load from 1952 through 1984 for 43 stations in the

Chesapeake Bay Watershed with at least 3 years of record ...............................................................19

7b. Average annual sediment yield from 1952 through 1984 for 43 stations in the Chesapeake

 Bay Watershed with at least 3 years of record ..................................................................................20

7c. Average annual discharge-weighted sediment concentration from 1952 through 1984 for

 43 stations in the Chesapeake Bay Watershed with at least 3 years of record..................................21

 8a–8c. Maps showing:

8a. Average annual suspended-sediment load from 1985 through 2001 for 35 stations in the

Chesapeake Bay Watershed with at least 3 years of record ...............................................................27

8b. Average annual sediment yield from 1985 through 2001 for 35 stations in the Chesapeake

Bay Watershed with at least 3 years of record ...................................................................................28

8c. Average annual discharge-weighted sediment concentration from 1985 through 2001 for

35 stations in the Chesapeake Bay Watershed with at least 3 years of record ...................................29

9. Map showing location of stations in the Chesapeake Bay Watershed used in the analysis of 

instantaneous suspended-sediment concentration on percentiles and sediment-transport

curves from 1985 through 2002..................................................................................................................40

 10a–10c. Maps showing:

10a. The 10th percentile of suspended-sediment concentration for 51 stations draining the

Chesapeake Bay Watershed with at least 3 years of record and at least 10 samples

in a given year ...................................................................................................................................41

10b. The median (50th percentile) of suspended-sediment concentration for 51 stations 

draining the Chesapeake Bay Watershed with at least 3 years of record and

at least 10 samples in a given year ....................................................................................................42

10c. The 90th percentile of suspended-sediment concentration for 51 stations draining the

Chesapeake Bay Watershed with at least 3 years of record and at least 10 samples

in a given year ...................................................................................................................................43

 11a–e. Graphs showing sediment-transport curves for the stream-gaging stations on / in the:

 a. Eastern Shore of Maryland and Delaware .................................................................................................45

 b. Susquehanna River Basin ..........................................................................................................................46

 c. Patuxent River Basin..................................................................................................................................51

 d. Potomac River Basin..................................................................................................................................52

 e. Pamunkey and Mattaponi River Basins .....................................................................................................54

 12a–h. Graphs showing sediment-transport curves normalized by drainage area separated into 

eight classes of drainage area:

 a. Class A, >9,650–27,100 square miles........................................................................................................55

 b. Class B, >965–9,650 square miles.............................................................................................................55

 c. Class C, >386–965 square miles ................................................................................................................55

 d. Class D, >193–386 square miles................................................................................................................55

 e. Class E, >96.5–193 square miles ...............................................................................................................56

 f. Class F, >38.6–96.5 square miles ..............................................................................................................56

 g. Class G, >7.70–38.6 square miles..............................................................................................................56

 h. Class H, 0.36–7.70 square miles................................................................................................................56
v

Tables

1. Period of record for suspended-sediment loads and instantaneous suspended-sediment concentrations 

used in this report, drainage areas of collection stations, and sources used in the computation of

suspended-sediment loads ...................................................................................................................................3

2. Summary of sediment data collected from River Input Monitoring stations, 1985 through 2001 ........................18

3. Summary of sediment data for water years 1952 through 1984 ............................................................................22

4. Rankings of sediment loads, yields, and discharge-weighted sediment concentrations, from highest (1)

to lowest (43) values, for stations operating from water years 1952 through 1984 ..........................................26

5. Summary of sediment data for water years 1985 through 2001 ............................................................................30

6. Rankings of sediment loads, yields, and discharge-weighted sediment concentrations, from highest (1)

to lowest (43) values, for stations operating from water years 1985 through 2001 ..........................................34

7. Summary of instantaneous suspended-sediment concentration data for stations used in this report for 

water years 1985 through 2002, including 10th, 50th, and 90th percentiles.......................................................36

8. Rankings of 10th, 50th, and 90th percentiles of suspended-sediment concentrations from highest (1) 

to lowest (51) values..........................................................................................................................................44
vi

Conversion Factors

_____________________________________________________________________________________________________________________________________

Multiply By To obtain

_____________________________________________________________________________________________________________________________________

Length

foot (ft) 0.3048 meter

mile (mi) 1.609 kilometer

mile, nautical (nmi) 1.852 kilometer

yard (yd) 0.9144 meter

Area

acre 4,047 square meter

acre 0.4047 hectare

acre 0.4047 square hectometer

acre 0.004047 square kilometer

square foot (ft2 ) 929.0 square centimeter

square foot (ft2 ) 0.09290 square meter

square inch (in2 ) 6.452 square centimeter

section (640 acres or 1 square mile) 259.0 square hectometer

square mile (mi2 ) 259.0 hectare

square mile (mi2 ) 2.590 square kilometer

Flow rate

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

cubic foot per second 0.01093 cubic meter per second 

 per square mile [(ft3/s)/mi2 ] per square kilometer

Mass

ton, short (2,000 lb) 0.9072 megagram

ton, long (2,240 lb) 1.016 megagram

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

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

ton per day per 0.3503 megagram per day

 square mile [(ton/d)/mi2 ] per square kilometer

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

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

_____________________________________________________________________________________________________________________________________

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

Note to USGS users: Use of hectare (ha) as an alternative name for square hectometer (hm2) is restricted to the 

measurement of small land or water areas. Use of liter (L) as a special name for cubic decimeter (dm3) is restricted to the 

measurement of liquids and gases. No prefix other than milli should be used with liter. Metric ton (t) as a name for megagram

(Mg) should be restricted to commercial usage, and no prefixes should be used with it.
Introduction 1

Summary of Suspended-Sediment Data for Streams Draining the 

Chesapeake Bay Watershed, Water Years 1952–2002

By Allen C. Gellis, William S.L. Banks, Michael J. Langland, and Sarah K. Martucci

Abstract

U.S. Geological Survey suspended-sediment 

data from 1952 to 2002 from selected stream-gaging stations draining the nontidal parts of the 

Chesapeake Bay Watershed were summarized to 

identify areas in the Watershed with high suspended-sediment loads, yields, and concentrations. 

The suspended-sediment load data were separated 

into two periods, 1952–1984 and 1985–2001. In 

1985, the Chesapeake Bay Program began recommending sediment regulations, so 1985 represents 

an important break in the data. The instantaneous 

suspended-sediment concentration data were 

examined for the period 1985–2002.

Suspended-sediment load data collected from 

43 stations from 1952–1984, with a minimum of 

3 years of record, indicated that the two highest 

average annual suspended-sediment loads were for 

stations on the main stem of the Potomac and 

Susquehanna Rivers. The highest average annual 

sediment yields and discharge-weighted sediment 

concentrations were for streams draining the metropolitan Washington, D.C. area, possibly related 

to urbanization. Data from 1985 through 2001 

that were collected from 35 stations with a minimum of 3 years of record showed that the highest 

average annual suspended-sediment loads were 

also on the main stem of the Potomac and 

Susquehanna Rivers. Four of the six highest 

average annual sediment yields and dischargeweighted sediment concentrations for 1985–2001 

were for stations draining to the Conestoga River, 

a tributary of the Susquehanna River.

Examination of percentiles (10th, 50th, and 

90th) of instantaneous suspended-sediment concentrations for 51 stations with a minimum of 

3 years of data and at least 10 samples in a year 

indicated that streams that drain to the Conestoga 

River had the highest suspended-sediment concentrations. Sediment-transport curves for the 

51 stations were separated into classes by drainage-area size. Five of the eight drainage-area 

classes showed that streams draining the 

Susquehanna River Basin had the highest suspended-sediment concentrations. Three of the 

Susquehanna River Basin drainage-area classes 

were in the Conestoga River Basin. Agriculture is 

the dominant land use in the Conestoga River 

Basin and may be an important source of sediment 

leading to the high sediment yields and instantaneous suspended-sediment concentrations, but further research is needed to quantify the importance 

of agriculture in relation to other sources of sediment in the Conestoga River Basin.

Introduction

The Chesapeake Bay is the largest estuary in the United 

States, draining over 64,000 mi2 (square miles). Much of the 

habitat in the Chesapeake Bay is degraded because of sediment (Langland and others, 1995). Suspended sediment in 

the water column can decrease the light available for submerged aquatic vegetation (SAV), and excess sediment can 

bury benthic habitats. Nutrients and toxic materials that contaminate habitats can also attach to suspended sediment 

(Darrell and others, 1999). Goals to reduce sediment loads 

by the year 2010 have been established by the U.S. Environmental Protection Agency (USEPA). To achieve these goals 

and reduce suspended-sediment loads and suspended-sediment concentrations in the Chesapeake Bay, identification of 

source areas of sediment is necessary. Watershed sediment 

sources can be separated into sediment originating from 

upland land uses (such as agriculture, mining, and construction) and sediment eroded from channel corridors (such as 

the channel bed and banks).

The U.S. Geological Survey (USGS) collected suspended sediment to determine daily sediment loads at 

selected stream-gaging stations in the Chesapeake Bay 

Watershed from water years (WY) 1952 through 1999 (fig. 

1, table 1). A WY is defined as October 1 of the previous 
2 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Introduction 3

 

Table 1. Period of record for suspended-sediment loads and instantaneous suspended-sediment 

concentrations used in this report, drainage areas of collection stations, and sources used in 

the computation of suspended-sediment loads

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the ESTIMATOR model, and RIM is sediment data from 

the River Input Monitoring stations. Water Year is from October 1 of the previous year to September 30 of the current year]

Station name Station

identification

number

Period of

record for

annual loads

(water year)

Annual load

computation

sources

Period of 

record for

instantaneous

suspendedsediment data

(water year)

Drainage 

area,

square

miles

Eastern Shore 

Nassawango Creek near Snow Hill, MD 01485500 1999–2002 44.9

Nanticoke River near Bridgeville, DE 01487000 1994–2002 75.4

Choptank River near Greensboro, MD 01491000 Estimator/

USGS daily/

RIM

1985–2002 113

Chesterville Branch near Crumpton, MD 01493112 1972–2001 1996–2002 6.12

Susquehanna River 

Corey Creek near Mainesburg, PA 01516500 1955, 1957, 1960–

1967

USGS daily 12.2

Elk Run near Mainesburg, PA 01517000 1955–1956, 1958,

1960–1962, 1966–

1967

USGS daily 10.2

Tioga River at Tioga, PA 01518000 1973–1978 Estimator 282

Tioga River at Lindley, NY 01520500 1975–1980 USGS daily 771

Chemung River at Chemung, NY 01531000 1975–1977 USGS daily 2,506

Susquehanna River at Towanda, PA 01531500 1985–1996 Estimator 1985–1993 7,797

Susquehanna River at Danville, PA 01540500 1975–1996 Estimator/

USGS daily

1985–1995 11,220

Young Womans Creek near Renovo, PA 01545600 1973–1979, 1981,

1983, 1985–1992

Estimator 46.2

Wilson Creek above Sand Run near Antrim, PA 01548408 1979–1981, 1985–

1996

USGS daily 6,847

Blockhouse Creek Tributary at Liberty, PA 01549100 1973–1977 USGS daily 1.08

Blockhouse Creek at Buttonwood, PA 01549300 1973–1977 USGS daily 22.3

Steam Valley Run at Buttonwood, PA 01549350 1973–1977 USGS daily 5.34

Blockhouse Creek near English Center, PA 01549500 1973–1977 USGS daily 37.7

West Branch Susquehanna River at Lewisburg, PA 01553500 1975–1984 USGS daily 1985–1995 6,847

Susquehanna River at Sunbury, PA 01554000 1973–1977 Estimator 18,306

East Mahantango Creek at Klingerstown, PA 01555400 1993–2000 44.7

Bobs Creek near Pavia, PA 01559795 1993–2000 16.6

Raystown Branch Juniata River at Saxton, PA 01562000 1988–1992 Estimator 1985–1993 756

Juniata River at Newport, PA 01567000 1985–1996 Estimator 3,355

Bixler Run near Loysville, PA 01567500 1955–1970 USGS daily 15

Sherman Creek at Shermans Dale, PA 01568000 1985–1996 Estimator 1985–1995 207

Conodoguinet Creek near Hogestown, PA 01570000 1985–2002 470

Conodoguinet Creek Tributary No. 1 near Enola, PA 01570100 1971–1976 USGS daily 0.77

Conodoguinet Creek Tributary No. 2 near Enola, PA 01570200 1973–1976 USGS daily 0.76

Conodoguinet Creek Tributary No. 2A near Enola, PA 01570230 1973–1976 USGS daily 0.7

Conodoguinet Creek Tributary No. 2B near Enola, PA 01570260 1973–1976 USGS daily 0.65

Conodoguinet Creek Tributary No. 3 near Enola, PA 01570300 1970–1976 USGS daily 0.38

Susquehanna River at Harrisburg, PA 01570500 1964–1966, 1968,

1972–1991

Estimator/

USGS daily

24,100

Paxton Creek near Penbrook, PA 01571000 1985–1994 11.2

Cedar Run at Eberlys Mill, PA 01571490 1993–1997 12.6
4 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 1. Period of record for suspended-sediment loads and instantaneous suspended-sediment 

concentrations used in this report, drainage areas of collection stations, and sources used in 

the computation of suspended-sediment loads—Continued

Station name Station

identification

number

Period of

record for

annual loads

(water year)

Annual load

computation

sources

Period of 

record for

instantaneous

suspendedsediment data

(water year)

Drainage

area,

square

miles

Susquehanna River—Continued

Lower Little Swatara Creek at Pine Grove, PA 01572000 1982–1984 USGS daily 34.3

Swatara Creek at Harper Tavern, PA 01573000 1960, 1977–1979 USGS daily 337

Swatara Creek near Hershey, PA 01573560 1985–1989 Estimator 483

Brush Run, Site 2, near McSherrystown, PA 01573810 1985–1991 0.38

West Conewago Creek near Manchester, PA 01574000 1985–1994 510

Codorus Creek near York, PA 01575500 1985–1989 Estimator 1985–1990 222

Codorus Creek at Pleasureville, PA 01575585 1985–1989 Estimator 1985–1994 267

Susquehanna River at Marietta, PA 01576000 1985–1996 Estimator 25,998

Little Conestoga Creek site 3A near Morgantown, PA 0157608335 1986, 1988–1991 Estimator 1.00

Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 1993–1995 Estimator 54

Conestoga River at Conestoga, PA 01576754 1985–1996 USGS daily 470

Susquehanna River at Conowingo, MD 01578310 1980–2001 Estimator/

USGS daily

1985–2002 27,100

Little Conestoga Creek near Churchtown, PA 01576085 1985–1992 Estimator 1985–1995 6

Big Spring Run near Willow Street, PA 01576521 1993–2001 1.77

North Fork Unnamed Tributary to Big Spring Run at

 Lampeter, PA

01576527 1993–2001 0.36

Unnamed Tributary to Big Spring Run at Lampeter, PA 01576529 1993–2001 1.42

Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 1992–1995 54.2

Conestoga River at Conestoga, PA 01576754 1985–1995 470

Pequea Creek at Martic Forge, PA 01576787 1985–1995 148

Bald Eagle Creek near Fawn Grove, PA 01577400 1986–1990 0.43

Patuxent River 

Patuxent River near Unity, MD 01591000 1986, 1990, 1993,

1995

Estimator 1986–2000 35

Little Patuxent River at Savage, MD 01594000 1987, 1988, 1990 Estimator 1985–2000 98

Patuxent River near Bowie, MD 01594440 1985–2001 USGS daily/

RIM

1985–2002 348

Western Branch at Upper Marlboro, MD 01594526 1986–2000 89.7

Hunting Creek near Huntingtown, MD 01594670 1989–1992 Estimator 1986–1998 9.4

Killpeck Creek at Huntersville, MD 01594710 1986–1989, 1991,

1994–1996

Estimator 1986–1997 3.26

Potomac River 

North Branch Potomac River near Cumberland, MD 01603000 1966–1978, 1981–

1982

Estimator/

USGS daily

877

Conococheague Creek at Fairview, MD 01614500 1968–1980, 1993–

1996

USGS daily 1985–2001 495

Muddy Creek at Mount Clinton, VA 01621050 1993–2001 14.2

South Fork Shenandoah River at Front Royal, VA 01631000 1954–1956 USGS daily 1985–2001 1,642

North Fork Shenandoah River near Strasburg, VA 01634000 1985–2001

Potomac River at Point of Rocks, MD 01638500 1961–1992 USGS daily 9,651

Monocacy River at Bridgeport, MD 01639000 1989–1995 Estimator/

USGS daily

173
Introduction 5

 

Table 1. Period of record for suspended-sediment loads and instantaneous suspended-sediment 

concentrations used in this report, drainage areas of collection stations, and sources used in 

the computation of suspended-sediment loads—Continued

Station name Station

identification

number

Period of

record for

annual loads

(water year)

Annual load

computation

sources

Period of 

record for

instantaneous

suspendedsediment data

(water year)

Drainage 

area,

square

miles

Potomac River—Continued

Monocacy River at Reichs Ford Bridge near 

 Frederick, MD

01643020 1961–1966, 1968–

1983, 1985–1992

USGS daily 817

Smilax Branch at Reston, VA 01644295 1972–1975 USGS daily 0.32

Snakeden Branch at Reston, VA 01645784 1974–1978 USGS daily 0.79

Potomac River at Chain Bridge at Washington, D.C. 1 01646580 1979–2001 Estimator/

USGS daily/

RIM

1985–2002 11,570

North Branch Rock Creek near Norbeck, MD 01647720 1972–1976 Estimator 9.73

North Branch Rock Creek near Rockville, MD 01647740 1968–1977 USGS daily 12.5

Northwest Branch Anacostia River near Colesville, MD 01650500 1963–1975 USGS daily 21.1

Accotink Creek near Annandale, VA 01654000 1985–2001 23.5

Cedar Run near Aden, VA 01656100 1985–1988,

1996–1999

155

Cedar Run at Route 646 near Aden, VA 01656120 1997–1999 USGS daily 1996–2000 175

South Fork Quantico Creek near Independent Hill, VA 01658500 1985–2001 7.64

Cannon Creek near Garrisonville, VA 01660380 1994–1997 10.2

Beaverdam Run near Garrisonville, VA 01660500 1997–2001 12.7

Rappahannock River

Hazel River at Rixeyville, VA 01663500 1953–1955 USGS daily 287

Rappahannock River at Remington, VA 01664000 1953–1993 USGS daily 620

Rapidan River near Culpeper, VA 01667500 1952–1965 USGS daily 472

Rappahannock River near Fredericksburg, VA 01668000 1989–2001 RIM 1,596

York River

Pamunkey River near Hanover, VA 01673000 1976–1980, 1991–

2001

Estimator/RIM 1985–2001 1,081

Mattaponi River near Beulahville, VA 01674500 1991–2001 RIM 1985–1988

1989–2001

601

James River 

James River at Buchanan, VA 02019500 1952–1956 USGS daily 2,075

James River at Scottsville, VA 02029000 1952–1956 USGS daily 4,584

James River at Cartersville, VA 02035000 1974–1983, 1987–

2001

Estimator/RIM 6,259

Appomattox River at Matoaca, VA 02041650 1990–2001 RIM 1,340

 1 Discharge is measured at Potomac River near Washington D.C., Little Falls Pumping Station (01646500), 1.2 miles upstream of Chain Bridge.
6 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

calendar year to September 30 of the current calendar year. 

The methods of suspended-sediment sampling and dailyload computation may have differed for each station, including frequency of suspended-sediment sampling, instruments 

used to collect suspended sediment, and methods used to 

compute suspended-sediment load. The last active dailyload sediment station ceased operation in 1999 (Cedar Run 

at Route 646 near Aden, Virginia). Instantaneous suspended-sediment data were collected at the daily-load stations. Instantaneous suspended-sediment data were also 

collected as part of water-quality sampling programs, such as 

the National Stream Quality Accounting Network 

(NASQAN), but suspended-sediment daily loads were never 

computed. Langland and others (1995) used a load-estimator model (ESTIMATOR) to compute monthly and annual 

suspended-sediment loads from the instantaneous suspended-sediment data for 127 sites in the Chesapeake Bay 

Watershed where daily loads had not previously been computed. Beginning in 1985, the USGS began estimating 

monthly and annual suspended-sediment loads using the 

ESTIMATOR model for nine major tributaries to the Chesapeake Bay, referred to as the River Input Monitoring (RIM) 

stations (Darrell and others, 1999).

Purpose and Scope

The USGS is engaged in several studies to identify 

sediment sources and sediment transport to the Chesapeake 

Bay. The purpose of this report is to provide a comprehensive summary of USGS data on suspended-sediment loads 

and concentrations from 1952 through 2002 for selected 

stream-gaging stations draining the nontidal parts of the 

Chesapeake Bay Watershed, and to identify areas in the 

Chesapeake Bay Watershed with high suspended-sediment 

loads, yields, and concentrations. The sediment data 

described in this report will provide useful information to 

Chesapeake Bay water-resources managers for identifying 

major source areas of sediment by drainage basin.

Previous Studies

Several studies relating sediment yield to land use have 

been conducted in the Chesapeake Bay Watershed (Guy and 

Ferguson, 1962; Jones, 1966; Williams and Reed, 1972). To 

assess possible sediment sources on a regional scale, 

Williams and Reed (1972) investigated sediment yields at 

33 USGS stream-gaging stations in the Susquehanna River 

Basin, using data from 1962 to 1967. For basins draining 

more than 100 mi 2, sediment yield was related to mining, 

geologic history, and physiographic region (Williams and 

Reed, 1972). The highest sediment yields (greater than 

200 tons/mi 2 , or tons per square mile) occurred in the glaciated portions of the Appalachian Low Plateau Province, 

coal-mining areas of the Valley and Ridge Province, and the 

Piedmont Province. The lowest sediment yields were found 

in subbasins of the Valley and Ridge Province draining more 

than 25 percent limestone. Internal drainage, presumably of 

karst topography, was cited as the cause for the low sediment 

yields in the limestone terrain.

Jones (1966) evaluated sediment data from a pairedbasin study, Corey Creek (12.2 mi2 ) and Elk Run (10.2 mi 2 ) 

in northern Pennsylvania, to determine the effects of land 

treatment on sediment yields. The Corey Creek Basin was 

chosen for extensive conservation treatments. Elk Run, a 

similar basin where only minor conservation treatments were 

applied, served as an external control to evaluate possible 

hydrologic changes resulting from treatments in Corey 

Creek. Sediment loads over the study period (1954 through 

1960) decreased 11 percent in Corey Creek relative to 

Elk Run. Conservation practices such as converting land 

cover from cropland to grass were cited as the main cause for 

the decrease in sediment loads in Corey Creek. Extensive 

water-diversion terraces, installed in 19 percent of the 

Corey Creek Basin to reduce runoff and sediment transport, 

had little effect on reducing sediment loads and caused a 

sharp rise in sediment yields during construction (Jones, 

1966).

Several other studies provide estimates of sediment 

yields from land disturbance in the Chesapeake Bay Watershed region. Guy and Ferguson (1962) reported yields of 

25,000 to 50,000 tons/mi 2 resulting from construction work 

around Washington, D.C. Wolman (1967) also reported sediment yields exceeding 100,000 tons/mi 2 from construction 

activities in the Washington, D.C. area. Roberts and Pierce 

(1976) suggested that the Patuxent River more than doubled 

its sediment yield after urbanization (408 to 983 tons/mi 2 ).

Brown and others (1988) used 10Be (an isotope of 

beryllium) to estimate soil erosion in 48 basins of the eastern 

United States, including 10 basins that drain to the 

Chesapeake Bay. For the entire data set, the highest rates of 

erosion were observed in the streams in the Piedmont 

Physiographic Province and the lowest rates were observed 

in streams in the Coastal Plain Province. The difference in 

erosion rates between Piedmont and Coastal Plain streams 

was attributed to differences in land use and stream gradient. 

Farming, which has occurred in the Piedmont Province for 

two centuries, has disturbed the topsoil and has led to high 

rates of soil erosion, as well as sediment with higher concentrations of 10Be. Compared to Coastal Plain streams, the 

higher slopes in Piedmont watersheds have also contributed 

to higher erosion rates. Annual pre-colonization sediment 

yield for the Piedmont was estimated to be 34.3 tons/mi 2 , a 

value that is similar to modern undisturbed basin sediment 

yields (Brown and others, 1988).

Langland and others (1995) used suspended-sediment 

data collected from 127 nontidal sites draining the 

Chesapeake Bay Watershed to examine the influence of land 

cover on total suspended solids (TSS) and suspended-sediment concentrations. They found that the largest median 

concentration of suspended sediment was in the upper 

Potomac River Basin, and that the highest concentrations of 

suspended sediment were in the Susquehanna River Basin. 

Correlations of annual sediment yields to land use, computed 

with a log-linear multiple regression model, indicated that 

basins with the highest percentage of agriculture had the 
Methods of Study 7

highest sediment yields. Basins with the highest percentage 

of forest cover had the lowest sediment yields.

Suspended-sediment concentrations analyzed for four of 

the RIM stations from 1985 through 1996 (Susquehanna, 

Potomac, Patuxent, and Choptank Rivers) (Darrell and others, 1999) showed the Patuxent River had the highest median 

suspended-sediment concentrations (45 mg/L, or milligrams 

per liter). The Potomac River had the highest median-annual 

sediment yield (175 tons/mi2 ) (Darrell and others, 1999).

Methods of Study

Two types of suspended-sediment data were analyzed in 

this report, suspended-sediment loads and instantaneous suspended-sediment concentrations. The data were acquired 

from a variety of sources. Suspended-sediment load data 

were obtained from: (1) daily sediment stations operating in 

the Chesapeake Bay Watershed (USGS Water Resources 

Data Reports for Maryland (1962–93), New York (1975–80), 

Pennsylvania (1952–86), and Virginia (1952–99)), (2) ESTIMATOR model runs (Langland and others, 1995), (3) RIM 

stations (Belval and Sprague, 1999), (4) the USGS National 

Water Information System (NWIS) data base, and

(5) the USGS web site for suspended-sediment data (U.S. 

Geological Survey, 2003). Instantaneous measurements of 

suspended-sediment concentration and discharge were compiled from NWIS.

In this report, the term “watershed” is used to describe 

the entire area that drains to the Chesapeake Bay. The term 

“basin” is used to describe drainages within the Chesapeake 

Bay Watershed that are associated with major rivers: the 

Choptank, James, Patuxent, Potomac, Rappahannock, 

Susquehanna, and York Rivers. Drainage areas within 

basins are referred to as “subbasins.” Tables and plots of the 

suspended-sediment data are presented according to major 

drainage basin.

Suspended-sediment loads obtained from USGS daily 

suspended-sediment load stations and the ESTIMATOR 

model results were summed by WY and averaged to calculate an average annual suspended-sediment load for each station. All annual data presented in this report are based on 

WY, rather than calendar year, and only years with 12 complete months of data were used. Only stations with at least 

3 complete WYs of record were included in this study, and 

the years did not have to be consecutive. If for a given WY a 

station had loads reported by both a daily-load station and 

from the ESTIMATOR model, only the data from the dailyload station were used. Suspended-sediment load data were 

normalized by drainage area to calculate sediment yield 

(tons/mi2 ). Guy (1964) determined that the dischargeweighted concentration of sediment for a storm event was a 

better dependent variable than sediment load for factors that 

affect storm period sediment transport, so WY suspendedsediment loads also were normalized by WY runoff to 

calculate a discharge-weighted sediment concentration 

(mg/L). WY runoff was obtained from NWIS or USGS 

Water Resources Data Reports for Maryland, New York, 

Pennsylvania, and Virginia (1952–99).

Suspended-sediment load, yield, and concentration data 

were analyzed for two periods—1984 and earlier, and 1985 

and later. In 1985, the Chesapeake Bay Program began 

recommending sediment and nutrient regulation, so 1985 

represents an important break in the data.

To determine if average WY suspended-sediment loads, 

yields, and discharge-weighted sediment concentrations at 

each station for their respective collection periods were 

representative of longer-term flow conditions, the average 

WY mean-daily discharge was calculated for the sedimentcollection period and compared to the mean-daily discharge 

for the entire period of streamflow record. Information on 

historical streamflow records was obtained from NWIS.

The Chesapeake Bay River Input Monitoring (RIM) program was established in the mid–1980s to quantify loads and 

long-term trends in suspended sediment entering the tidal 

part of the Chesapeake Bay Basin from its nine major tributaries (Appomattox, Choptank, James, Mattaponi, 

Pamunkey, Patuxent, Potomac, Rappahannock, and 

Susquehanna) (Darrell and others, 1999). The RIM stations 

are near the “Fall Line,” a natural boundary between the 

Piedmont and Coastal Plain Physiographic Provinces in the 

eastern United States, where there is a relatively large 

change in elevation (fig. 1). This line roughly represents the 

boundary between the tidal and nontidal parts of each river. 

The RIM stations monitor approximately 78 percent of the 

streamflow entering Chesapeake Bay from the nontidal part 

of its watershed (Darrell and others, 1999). The RIM sediment data for the period 1985 through 2001 were examined 

as part of this report.

Suspended-sediment concentrations in tributaries to the 

Chesapeake Bay were determined from samples collected 

using methods described by Edwards and Glysson (1988). 

In most cases, this involved the use of depth-integrating 

samplers deployed by either the Equal-Width Increment or 

Equal-Discharge Increment techniques, or with automatic 

samplers (Edwards and Glysson, 1988). Analyses of suspended-sediment concentrations and particle-size distributions were performed by methods described by the American 

Society for Testing and Materials (ASTM, 1999), Knott and 

others (1992), and Guy (1969). Porterfield (1972) and 

Koltun and others (1994) describe the methodology that 

was used for computing daily suspended-sediment loads. 

Daily suspended-sediment loads obtained for this report 

were generally computed by the subdivision technique 

(Porterfield, 1972) but other methods, such as the sediment 

rating curve-flow duration method (Porterfield, 1972), may 

also have been used. In the subdivision method, individual 

samples of suspended-sediment concentrations are plotted 

and a continuous trace of suspended-sediment concentration 

is drawn between concentration values.

The relation between instantaneous water discharge and 

suspended-sediment concentration is referred to as a sediment-transport curve (Glysson, 1987). In the computation of 
8 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

suspended-sediment loads, sediment-transport curves were 

used to estimate suspended-sediment concentrations for 

periods when samples were not sufficient to define concentration by time. During periods of low flow, the average 

daily suspended-sediment concentration (mg/L) is multiplied 

by the average discharge (ft3/s, or cubic feet per second) and 

a coefficient (0.0027) to compute sediment in tons per day. 

During periods of higher flows or rapidly varying flows, the 

suspended-sediment concentrations and water discharge are 

divided into smaller periods. The mid-interval or mean 

interval of suspended sediment and discharge for each period 

are multiplied together and by 0.0027 to compute a sediment 

load for each period. Loads computed for each period are 

summed to obtain a daily load. Porterfield (1972) states that 

the visual procedure to construct continuous temporal concentration curves is the most common and accurate method 

when supplemented with sediment-transport curves.

The ESTIMATOR model uses a linear regression 

method, whereby the line of best fit developed from the relation of mean-daily discharge to suspended sediment or TSS 

is used to calculate suspended-sediment load (Cohn and 

others, 1989, 1992). With this method, a curvilinear relation 

between measurements of stream discharge and suspendedsediment loads is derived on a logarithmic scale. The empirical relation is applied to stream discharges for periods of 

interest (monthly or annual). Langland and others (1995) 

used the ESTIMATOR model to quantify monthly and 

annual suspended-sediment loads for 127 sites in the 

Chesapeake Bay Watershed. Monthly and annual loads for 

the RIM stations also were calculated with the ESTIMATOR 

model.

Average annual suspended-sediment loads, sediment 

yields, and discharge-weighted sediment concentrations in 

this report are displayed spatially for two time periods—

1984 and earlier, and from 1985 through 2001, using a 

geographical information system (GIS). The RIM station 

data, which are representative of a major portion of the 

Chesapeake Bay Watershed, are shown separately to illustrate sediment transport at the major watershed scale. Data 

from the RIM network were used to calculate sediment loads 

starting in 1985; therefore, only the period from 1985 

through 2001 is displayed.

In this report, instantaneous measurements of suspendedsediment concentrations were analyzed and interpreted 

through examination of the distribution (percentiles) of suspended-sediment concentrations and analysis of sedimenttransport curves. Only sediment data and discharge data 

from 1985–2002 were used to compute percentiles and sediment-transport curves. In addition, only stations with a minimum of 3 complete years of data and 10 or more suspendedsediment samples in a given year were used. Percentiles 

(10th, 50th, and 90th ) for instantaneous measurements of suspended sediment were determined using standard statistical 

software (SAS Institute Inc., Version 6, 1994).

To determine whether the suspended-sediment samples 

were biased towards either a low- or high-flow condition, 

mean-daily discharge values measured on days when suspended-sediment samples were collected were compared to 

mean-daily discharge values for all the years meeting the 

criteria listed above that contained suspended-sediment data. 

Mean-daily discharges were retrieved from the NWIS data 

base. A two-sided, Mann-Whitney-Wilcoxon test (Helsel 

and Hirsch, 1992) was used to determine if the ranked meandaily discharges differed in the two populations—the sample 

population of mean-daily discharges on days when suspended-sediment samples were collected and the population 

of mean-daily discharge values for all the years that contained sediment data. The null hypothesis that the distribution of data of the two populations was similar was rejected 

at the 95-percent confidence level (alpha = 0.05).

Sediment-transport curves have been used to determine 

impaired streams and undisturbed or reference streams 

(Simon and others, 2001; Troendle and others, 2002). 

Troendle and others (2002) created pooled dimensionless 

sediment-transport curves for 160 reference sites in the western United States. A dimensionless transport curve is created by normalizing each discharge value by the discharge at 

bankfull flow and each suspended-sediment value by the 

suspended-sediment concentration at bankfull flow. Bankfull flow is the discharge that occurs every 1.5 years. The 

dimensionless transport curve for Coon Creek, Wyoming, a 

timber-harvested basin, was shown to depart significantly 

from the reference transport curve, and was considered 

impaired.

Sediment-transport curves were generated for all stations 

in this study with at least 3 complete years of data and at 

least 10 suspended-sediment samples in a given year. The 

sediment-transport curves are shown with a line of best fit, 

determined using a standard computer-graphing package 

(SIGMAPLOT, SPSS, Inc., Version 7.0, 2001) to indicate 

the general trend in the data. It was not determined whether 

the slope of the line of best fit was statistically different from 

zero.

When plotted together, sediment-transport curves for different rivers may indicate rivers that have higher suspendedsediment concentrations at a given discharge. Because 

drainage area is a controlling factor in runoff and sediment 

transport, in order to compare sediment-transport curves 

between rivers with different contributing areas, sedimenttransport curves were separated by drainage-area classes. 

A metric scale provided order-of-magnitude divisions to 

classify drainage areas. Based on the number of sites and 

ensuring that no class had fewer than four sites, the following classes were used:
Methods of Study 9

Class A > 25,000–70,200 km2 (>9,650–27,100 mi2;

 (square kilometers) square miles)

Class B > 2,500–25,000 km2 (>965–9,650 mi2)

Class C > 1,000–2,500 km2 (>386–965 mi 2)

Class D > 500–1,000 km2 (>193–386 mi2)

Class E > 250–500 km2 (>96.5–193 mi2)

Class F > 100–250 km2 (>38.6–96.5 mi2)

Class G > 20–100 km2 (>7.70–38.6 mi2)

Class H > 0.93–20 km2 (0.36–7.70 mi 2)

There is still a broad range of drainage areas in each class. 

To minimize any influence of area, discharge was normalized by drainage area.

Limitations of Data and Methods of Analysis

Nine of the stations that operated from 1973 through 

1993 have suspended-sediment loads computed as daily 

loads and suspended-sediment loads computed by the 

ESTIMATOR method, for selected years, constituting a total 

of 36 years of comparable data. The individual records for 

each station were not obtained, but the daily suspended-sediment loads were most likely computed by the subdivision 

method; however, at times the flow duration method may 

have been used. Differences in load computations may 

occur between the subdivision method and the ESTIMATOR 

method. Walling (1977) reported load overestimates of 

280 percent when using a linear-regression method 

compared to the subdivision method. In contrast to these 

findings, Horowitz (2003) reported that the linear (or polynomial) regression method tends to under-predict high suspended-sediment concentrations, but can generate annual 

suspended-sediment load estimates within 20 percent. In 

this analysis, a comparison using both methods shows 

that ESTIMATOR has a tendency to calculate higher suspended-sediment loads than the method used for the dailyload computations, which were most likely calculated using 

the subdivision method (fig. 2). Figure 2 shows that the 

difference in suspended-sediment loads computed by 

ESTIMATOR and daily suspended-sediment loads is greater 

at the higher suspended-sediment loads.

Sediment-load computations at the four Virginia RIM 

stations (Pamunkey River near Hanover, Virginia, station 

01673000; Mattaponi River at Beulahville, Virginia, station 

01674500; James River at Cartersville, Virginia, station 

02035000; and Appomattox River at Matoaca, Virginia, 

station 02041650) (fig. 1, table 1) were based on TSS data. 

Gray and others (2000) showed that the TSS method tends to 

under-predict concentrations when the sand content of the 

sample exceeds about one-quarter of the sediment by weight. 

Therefore, load estimations based on TSS at the Virginia 

RIM stations could be underestimated.

Another major limitation is sample-collection methodology. At times, samplers other than isokinetic samplers, such 

as point samplers and bottles, may have been used to collect 

 

suspended sediment. Although samples should be collected 

at a minimum of 10 verticals in a cross section (Edwards and 

Glysson, 1988), sometimes a single vertical may have been 

used. Typically, several bottles are collected in association 

with a cross-sectional sample. Each bottle is sent to the laboratory for analysis of suspended-sediment concentration 

and composited to obtain a value. Bottles have sometimes 

been composited in the field with equipment such as a churn 

or cone splitter to obtain a single concentration. Because 

sample-collection methodology varied over time and space, 

it is difficult to quantify the errors associated with using 

methods other than those recommended by Edwards and 

Glysson (1988).

Sampling frequency is another important factor that can 

affect the accuracy of the annual suspended-sediment load 

computation. Because most rivers transport 80 to 90 percent 

of their annual load during storm runoff events (Meade and 

others, 1990), sediment sampling at high flows is favorable 

for a good sediment record. Continuous suspended-sediment sampling during the storm runoff hydrograph is also 

favorable for producing an accurate continuous sediment 

trace. The relation of suspended-sediment samples to high 

flows was not examined for the suspended-sediment load 

data.
10 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

Summary of Sediment Loads, Yields, and 

Discharge-Weighted Sediment 

Concentration s

Sixty-five stations with at least 3 complete years of 

record were selected for analysis of suspended-sediment 

load data (figs. 1 and 3). The greatest number of stations 

functioning concurrently (27) were in operation from 

1989–91 (fig. 3). The station with the longest record is the 

Rappahannock River at Remington, Virginia (station 

01664000), with 40 years of data (fig. 3). The distribution 

of drainage areas for all sediment stations operating from 

1952 through 2001 (n = 65) indicates that the most sediment 

stations operating at any time were in basins draining 

between 100 and 500 mi2, whereas the least number of sediment stations operating at any time were in basins draining 

50 and 100 mi2 (fig 4). Suspended-sediment loads are highly 

correlated to drainage area and to average annual mean-daily 

discharge for the sediment collection period (figs. 5a–b). 

Drainage area shows a weak, inverse relation to sediment 

yield and to discharge-weighted sediment concentration 

(figs. 5c–d). Schumm (1977) and Walling (1983) described 

decreasing sediment yield with increasing basin area as more 

sites in a basin become available for sediment storage.

River Input Monitoring Station Data, 1985–2001

The RIM stations provide data on suspended-sediment 

loads delivered to the tidal parts of the Chesapeake Bay 

Watershed. The RIM station data for 1985 through 2001 

show that the Potomac and Susquehanna Rivers had the two 

highest suspended-sediment loads (fig. 6a, table 2). When 

normalized by either drainage area or average annual runoff, 

the highest average annual sediment yields and average 

annual discharge-weighted sediment concentrations were in 

the Rappahannock and Potomac Rivers (figs. 6 b–c, and 

table 2). Although the Susquehanna River at Conowingo, 

Maryland (station 01578310) drains a large area (27,100 

mi2), the Susquehanna River at Conowingo, Maryland, has 

three large dams upstream that are trapping about two-thirds 

of the suspended-sediment load (Langland and Hainly, 

1997), thereby lowering the river’s sediment yields. The 

Choptank, Mattaponi, and Appomattox Rivers had the lowest average annual suspended-sediment loads, sediment 

yields, and discharge-weighted sediment concentrations (fig. 

6c, table 2).

Suspended-Sediment Data, 1952 through 1984 

Forty-three stations operating from 1952 through 1984 

had suspended-sediment load data with 3 or more years of 

record (figs. 7 a–c, table 3). Almost one-half of the stations 

(20) had average annual mean-daily discharge during the 

study period that was within 10 percent of the average 

annual mean-daily discharge for the entire period of record. 

Sixteen stations had average annual mean-daily discharges 

greater than 10 percent (10.5 to 27.3 percent) of the average 

WY mean-daily discharges for their respective periods of 

record. This could indicate that sediment loads for these stations could be higher under average flow conditions. Seven 

stations had average annual mean-daily discharge that was 

less than 10 percent (-11 to -23 percent) of the average 

annual mean-daily discharge for the period of record. At 

these stations, sediment loads could be lower than under 

average flow conditions. In summary, about one-half 

(46.5 percent) of the sediment data was not biased toward 

lower or higher flow conditions. About 37 percent of the 

sediment data were collected under flow conditions that 

were greater than 10 percent of the average mean-daily flow, 

and 16.3 percent of the sediment data were collected under 

flow conditions that were less than 10 percent of the average 

mean-daily flow.

For 1952 through 1984, the highest average annual 

suspended-sediment load was at the Potomac River at 

Chain Bridge, Washington, D.C. (2.92 x 106 tons/yr, or tons 

per year) (table 4). The next three highest average annual 

suspended-sediment loads were at stations on the 

Susquehanna River (Susquehanna River at Harrisburg, 

Pennsylvania, 2.88 x 106 tons/yr; Susquehanna River at 

Sunbury, Pennsylvania, 2.19 x 106 tons/yr; and Susquehanna 

River at Conowingo, Maryland, 1.64 x 106 tons/yr) (fig. 7a, 

tables 3–4). Suspended-sediment load is highly correlated to 

drainage area. The stations with the highest suspended-sediment loads also drain the largest area (table 3).

Normalizing average annual suspended-sediment loads 

by drainage area and runoff showed that streams in the 

Washington, D.C. area had the three highest sediment yields 

and discharge-weighted sediment concentrations (Snakeden 

Branch at Reston, Virginia–1,140 tons/mi 2/yr, or tons per 

square mile per year, 653 mg/L; Smilax Branch at Reston, 

Virginia–989 tons/mi 2/yr, 585 mg/L; and Northwest Branch 

Anacostia River near Colesville, Maryland–702 tons/mi 2/yr, 

660 mg/L) (figs. 7b–c; tables 3–4). The high sediment yields 

and sediment concentrations in the Washington, D.C. area 

could reflect construction and urbanization during the study 

period (Guy and Ferguson, 1962; Wolman, 1967).

The lowest average annual sediment yields and discharge-weighted sediment concentrations for stations 

with data collected between 1952–1984 were from 

Young Womans Creek in Pennsylvania (7.6 tons/mi 2/yr, 

4.3 mg/L), the Choptank River on Maryland’s Eastern Shore 

(21.9 tons/mi 2/yr, 16.0 mg/L), and the Pamunkey River in 

Virginia (22.3 tons/mi 2/yr, 20.2 mg/L) (figs. 3 b–c, table 3). 

The Young Womans Creek watershed in Pennsylvania is 

entirely forested (Hainly and Loper, 1997).

Suspended-Sediment Data, 1985 through 2001

Thirty-five stations had suspended-sediment load data 

from 1985 through 2001 with 3 or more years of record 

(figs. 8 a–c, table 5). Most of the stations (57 percent) had 

average annual mean-daily discharge for the collection 

period within plus or minus 10 percent of the average 

annual mean-daily discharge for the entire period of record. 

About one-third of the stations (31 percent) had an average 

annual mean-daily discharge that was 10 to 20 percent 

(-10 to -20 percent) lower than the mean-daily discharge for 

the period of record. Only three stations, Monocacy River 
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 11

at Bridgeport, Maryland (14.9 percent), Little Conestoga 

Creek site 3A near Morgantown (10.9 percent), and 

Conococheague Creek at Fairview, Maryland (48.2 percent), 

had average annual mean-daily discharges that were higher 

than 10 percent of the mean-daily discharge for the period of 

record. For these two stations, suspended-sediment loads 

may be higher than those measured during average flow 

conditions.

For the period 1985 through 2001, stations on the 

Potomac River had the highest and third highest average 

annual suspended-sediment load (Potomac River at 

Chain Bridge, Washington, D.C., 1.84 x 10 6 tons/yr, and 

Potomac River at Point of Rocks, Maryland, 

1.13 x 106 tons/yr, respectively) (fig. 8a, tables 5–6). The 

Potomac River at Chain Bridge is the RIM station for the 

Potomac River Basin. The second highest average annual 

suspended-sediment load was at the Susquehanna River at 

Marietta, Pennsylvania (1.70 x 106 tons/yr). This site is 

upstream of major reservoirs that may trap and remove 

sediment (table 6). When normalized by drainage area 

and runoff, four of the five highest average annual sediment 

yields and discharge-weighted sediment concentrations 

are for stations that drain to the Susquehanna River in 

Pennsylvania (Little Conestoga Creek near Churchtown, 

Pennsylvania; Little Conestoga Creek site 3 near 

Morgantown, Pennsylvania; Mill Creek at Eshelman Mill 

Road near Lyndon, Pennsylvania; and Raystown Branch 

Juniata River at Saxton, Pennsylvania) (figs. 8a–c, 

tables 5–6). Three of the four Pennsylvania stations are in 

the Conestoga River Basin (two stations on Little 

Conestoga Creek and one on Mill Creek). The Conestoga 

River Basin drains primarily agricultural land, which may be 

influencing the high sediment yields and concentrations. 
12 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 13
14 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 15
16 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 17
18 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 2. Summary of sediment data collected from River Input Monitoring stations, 1985 through 2001

[mg/L, milligrams per liter; Water Year is from October 1 of the previous year to September 30 of the current year.]

Period 

of record

for sediment

collection

(water year) Station name

Station

identification

number

Drainage

area

(square 

miles)

Average

water year 

suspendedsediment

load

(tons)

Average

water year

dischargeweighted

sediment

concentration

(mg/L)

1985–2001 Choptank River near Greensboro, MD 01491000 113 2,310 17.3

1985–2001 Susquehanna River at Conowingo, MD 01578310 27,100 1,110,000 29.9

1985–2001 Patuxent River near Bowie, MD 01594440 348 23,400 67.1

1985–2001 Potomac River at Chain Bridge at Washington, D.C. 1 01646580 11,570 1,840,000 157

1989–2001 Rappahannock River near Fredericksburg, VA* 01668000 1,596 527,000 299

1990–2001 Pamunkey River near Hanover, VA* 01673000 1,081 39,400 38.5

1991–2001 Mattaponi River at Beulahville, VA* 01674500 601 5,030 10.0

1987–2001 James River at Cartersville, VA* 02035000 6,259 608,000 83.4

1990–2001 Appomattox River at Matoaca, VA* 02041650 1,340 17,800 15.1

Period of

record for 

discharge

data Station name

Station

identification

number

Average

water year 

sediment

yield,

(tons per

square

mile)

Mean 

daily 

discharge

for sediment

collection

period,

(cubic feet

per second)

Mean

daily 

discharge

for period

of record,

(cubic feet

per second)

1949–2002 Choptank River near Greensboro, MD 01491000 20.4 135 132

1968–2002 Susquehanna River at Conowingo, MD 01578310 40.8 37,588 39,791

1978–2002 Patuxent River near Bowie, MD 01594440 67.3 355 367

1931–2002 Potomac River at Chain Bridge at Washington, D.C. 1 01646580 159 11,938 11,256

1908–2001 Rappahannock River near Fredericksburg, VA* 01668000 330 1,788 1,674

1942–2001 Pamunkey River near Hanover, VA* 01673000 36.5 1,039 1,010

1942–1987,

1990–2001

Mattaponi River at Beulahville, VA* 01674500 8.4 512 577

1900–2001 James River at Cartersville, VA* 02035000 97.2 7,404 7,161

1979–2001 Appomattox River at Matoaca, VA* 02041650 13.3 1,195 1,347

* Indicates total suspended solids were collected at the station.

1 Discharge is measured at Potomac River near Washington D.C., Little Falls Pumping Station (01646500), 1.2 miles upstream of Chain Bridge.
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 19
20 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 21
22 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 3. Summary of sediment data for water years 1952 through 1984

[USGS daily refers to daily-load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data from the 

River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

mg/L, milligrams per liter]

Period of

record for

sediment 

collection

(water

year)

Annual

load

computation

sources Station name

Station

identification

number

Drainage

area

(square

miles)

Eastern Shore

1972–1984 USGS daily/RIM Choptank River near Greensboro, MD 01491000 113

Susquehanna River 

1955–1957, 1960–1967 USGS daily Corey Creek near Mainesburg, PA 01516500 12.2

1955–1956, 1958, 1960–

 1962, 1966–1967

USGS daily Elk Run near Mainesburg, PA 01517000 10.2

1973–1978 Estimator Tioga River at Tioga, PA 01518000 282

1975–1980 USGS daily Tioga River at Lindley, NY 01520500 771

1975–1977 USGS daily Chemung River at Chemung, NY 01531000 2,506

1975–1984 Estimator Susquehanna River at Danville, PA 01540500 11,220

1973–1979, 1981, 1983 Estimator/USGS daily Young Womans Creek near Renovo, PA 01545600 46.2

1979–1981 USGS daily Wilson Creek above Sand Run near Antrim, PA 01548408 12.6

1973–1977 USGS daily Blockhouse Creek Tributary at Liberty, PA 01549100 1.08

1973–1977 USGS daily Blockhouse Creek at Buttonwood, PA 01549300 22.3

1973–1977 USGS daily Steam Valley Run at Buttonwood, PA 01549350 5.34

1973–1977 USGS daily Blockhouse Creek near English Center, PA 01549500 37.7

1975–1984 USGS daily/Estimator West Branch Susquehanna River at Lewisburg, PA 01553500 6,847

1973–1977 Estimator Susquehanna River at Sunbury, PA 01554000 18,306

1955–1970 USGS daily Bixler Run near Loysville, PA 01567500 15

1971–1976 USGS daily Conodoguinet Creek Tributary No. 1 near Enola, PA 01570100 0.77

1973–1976 USGS daily Conodoguinet Creek Tributary No. 2 near Enola, PA 01570200 0.76

1973–1976 USGS daily Conodoguinet Creek Tributary No. 2A near Enola, PA 01570230 0.7

1973–1976 USGS daily Conodoguinet Creek Tributary No. 2B near Enola, PA 01570260 0.65

1970–1976 USGS daily Conodoguinet Creek Tributary No. 3 near Enola, PA 01570300 0.38

1964–1966, 1968, 1972–

 1984

Estimator/USGS daily Susquehanna River at Harrisburg, PA 01570500 24,100

1982–1984 USGS daily Lower Little Swatara Creek at Pine Grove, PA 01572000 34.3

1960, 1977–1979 USGS daily Swatara Creek at Harper Tavern, PA 01573000 337

1980–1984 Estimator/USGS daily Susquehanna River at Conowingo, MD 01578310 27,100

Potomac River 

1966–1978, 1981–1982 USGS daily North Branch Potomac River near Cumberland, MD 01603000 877

1968–1980 USGS daily Conococheague Creek at Fairview, MD 01614500 495

1954–1956 USGS daily South Fork Shenandoah River at Front Royal, VA 01631000 1,642

1961–1984 USGS daily Potomac River at Point of Rocks, MD 01638500 9,651

1961–1966, 1968–1983 USGS daily Monocacy River at Reichs Ford Bridge near Frederick, MD 01643020 817

1972–1975 USGS daily Smilax Branch at Reston, VA 01644295 0.32

1974–1978 USGS daily Snakeden Branch at Reston, VA 01645784 0.79

1979–1984 1 Estimator/ USGS daily 1 Potomac River at Chain Bridge at Washington, D.C. 1 01646580 11,570

1972–1976 Estimator North Branch Rock Creek near Norbeck, MD 01647720 9.73

1968–1977 USGS daily North Branch Rock Creek near Rockville, MD 01647740 12.5

1963–1975 USGS daily Northwest Branch Anacostia River near Colesville, MD 01650500 21.1

1 Discharge is measured at Potomac River near Washington D.C., Little Falls Pumping Station (01646500), 1.2 miles upstream of Chain Bridge.
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 23

 

Table 3. Summary of sediment data for water years 1952 through 1984

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data from the 

River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

mg/L, milligrams per liter]

Average

water year

sediment

load

(tons)

Average

water year

dischargeweighted

sediment

concentration

(mg/L)

Average

water year

sediment

yield

(tons per

square

mile)

Mean daily

discharge

for sediment

period

(cubic feet

per second)

Mean daily

discharge

for period

of record

(cubic feet

per second) Period of streamflow record

Difference

of study 

period

mean daily

discharge

to period

of record

(in percent)

Station

identification

number

2,480 16.0 21.9 156 132 1949–2002 18.4 01491000

1,360 138 111 10.0 12.5 1955–2001 -19.9 01516500

1,650 149 162 11.2 11.0 1955–1978 2.0 01517000

11,200 25.2 39.8 451 380 1939–2001 18.7 01518000

310,400 325 403 969 812 1931–1994 19.3 01520500

828,300 275 331 3,056 2,578 1907–1909, 1912, 1916–2001 18.5 01531000

1,431,000 85.2 128 17,052 15,266 1906–2001 11.7 01540500

352 4.3 7.6 83.1 73.5 1966–2001 13.1 01545600

4,930 386 392 13.0 13.0 1979–1981 -0.2 01548408

317 190 293 1.7 1.7 1973–1977 -0.2 01549100

6,420 184 288 35.5 35.5 1973–1977 -0.1 01549300

700 65.7 131 10.8 10.8 1973–1977 0.3 01549350

10,300 155 272 67.2 58.4 1941–2001 15.0 01549500

432,000 35.7 63 12,284 10,796 1940–2001 13.8 01553500

2,192,000 69.7 120 31,964 26,626 1938–2001 20.0 01554000

999 67.3 66.6 15.1 19.5 1955–2001 -22.7 01567500

150 133 194 1.1 1.1 1970–1976 3.6 01570100

283 250 373 1.2 1.2 1973–1976 -4.0 01570200

170 177 243 1.0 1.0 1973–1976 -0.1 01570230

329 335 506 1.0 1.0 1973–1976 -0.3 01570260

160 258 410 0.6 0.6 1970–1976 0.6 01570300

2,880,000 81.3 120 35,979 34,212 1891–2001 5.2 01570500

5,730 81.4 167 71.5 58.2 1920–1932, 1982–1984 22.9 01572000

104,000 139 309 761 572 1920–2001 33.1 01573000

1,636,000 44.8 60.4 37,031 39,791 1968–2002 -6.9 01578310

157,000 121 179 1,318 1,287 1930–2002 2.4 01603000

65,900 90.1 133 743 597 1929–1991, 1993–2002 24.4 01614500

225,000 174 137 1,309 1,591 1931–2001 -17.7 01631000

1,145,000 118 119 9,884 9,437 1896–2002 4.7 01638500

187,000 196 229 965 939 1943–2002 2.7 01643020

316 585 989 0.55 0.4 1968–1978 30.8 01644295

903 653 1,140 1.40 1.4 1974–1978 0.3 01645784

2,918,000 224 252 13,234 11,256 1931–2002 1 17.6 01646580

1,950 128 201 15.6 11.8 1967–1977 31.8 01647720

601 37.9 48.0 16.1 16.1 1968–1977 0.0 01647740

14,800 660 702 22.8 22.4 1924–1983, 1999–2001 1.8 01650500
24 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 3. Summary of sediment data for water years 1952 through 1984—Continued

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data from the 

River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

mg/L, milligrams per liter]

Period of

record for

sediment 

collection

(water

year)

Annual

load

computation

sources Station name

Station

identification

number

Drainage

area

(square

miles)

Rappahannock River 

1953–1955 USGS daily Hazel River at Rixeyville, VA 01663500 287

1953–1984 USGS daily Rappahannock River at Remington, VA 01664000 620

1952–1956 USGS daily Rapidan River near Culpeper, VA 01667500 472

Pamunkey River 

1976–1980 Estimator Pamunkey River near Hanover, VA 01673000 1,081

James River 

1952–1956 USGS daily James River at Buchanan, VA 02019500 2,075

1952–1956 USGS daily James River at Scottsville, VA 02029000 4,584

1974–1983 Estimator James River at Cartersville, VA 02035000 6,259
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 25

 

Table 3. Summary of sediment data for water years 1952 through 1984—Continued

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data from the 

River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

mg/L, milligrams per liter]

Average

water year

sediment

load

(tons)

Average

water year

dischargeweighted

sediment

concentration

(mg/L)

Average

water year

sediment

yield

(tons per

square

mile)

Mean daily

discharge

for sediment

period

(cubic feet

per second)

Mean daily

discharge

for period

of record

(cubic feet

per second) Period of streamflow record

Difference

of study 

period

mean daily

discharge

to period

of record

(in percent)

Station

identification

number

47,800 164 166 295 338 1943–1992 -12.6 01663500

98,300 148 158 676 693 1943–2001 -2.4 01664000

74,000 166 157 453 535 1931–2002 -15.4 01667500

24,100 20.2 22.3 1,211 1,010 1942–2001 19.9 01673000

198,000 93.7 95.4 2,146 2,452 1911–2001 -12.5 02019500

623,700 136.9 136 4,623 5,208 1925–2001 -11.2 02029000

417,200 56.7 66.7 7,470 7,161 1900–2001 4.3 02035000
26 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 4. Rankings of sediment loads, yields, and discharge-weighted sediment concentrations, from 

highest (1) to lowest (43) values, for stations operating from water years 1952 through 1984

Station name

Station

identification

numbers

Suspendedsediment

load

ranking

Sediment

yield

ranking

Discharge-weighted

sediment 

concentration

ranking

Choptank River near Greensboro, MD 1491000 28 42 42

Corey Creek near Mainesburg, PA 1516500 31 33 22

Elk Run near Mainesburg, PA 1517000 30 22 19

Tioga River at Tioga, PA 1518000 23 40 40

Tioga River at Lindley, NY 1520500 11 6 6

Chemung River at Chemung, NY 1531000 7 9 7

Susquehanna River at Danville, PA 1540500 5 29 30

Young Womans Creek near Renovo, PA 1545600 36 43 43

Wilson Creek above Sand Run near Antrim, PA 1548408 27 7 4

Blockhouse Creek Tributary at Liberty, PA 1549100 38 11 12

Blockhouse Creek at Buttonwood, PA 1549300 25 12 13

Steam Valley Run at Buttonwood, PA 1549350 34 28 35

Blockhouse Creek near English Center, PA 1549500 24 13 18

West Branch Susquehanna River at Lewisburg, PA 1553500 9 37 39

Susquehanna River at Sunbury, PA 1554000 3 30 33

Bixler Run near Loysville, PA 1567500 32 36 34

Conodoguinet Creek Tributary No. 1 

near Enola, PA

1570100 43 18 24

Conodoguinet Creek Tributary No. 2

 near Enola, PA

1570200 40 8 9

Conodoguinet Creek Tributary No. 2A 

near Enola, PA

1570230 41 15 14

Conodoguinet Creek Tributary No. 2B

 near Enola, PA

1570260 37 4 5

Conodoguinet Creek Tributary No. 3 near Enola, PA 1570300 42 5 8

Susquehanna River at Harrisburg, PA 1570500 2 31 32

Lower Little Swatara Creek at Pine Grove, PA 1572000 26 20 31

Swatara Creek at Harper Tavern, PA 1573000 16 10 21

Susquehanna River at Conowingo, MD 1578310 4 38 37

North Branch Potomac River near Cumberland, MD 1603000 15 19 26

Conococheague Creek at Fairview, MD 1614500 19 27 29

South Fork Shenandoah River at Front Royal, VA 1631000 12 25 15

Potomac River at Point of Rocks, MD 1638500 6 32 27

Monocacy River at Reichs Ford Bridge

near Frederick, MD

1643020 14 16 11

Smilax Branch at Reston, VA 1644295 39 2 3

Snakeden Branch at Reston, VA 1645784 33 1 2

Potomac River at Chain Bridge at Washington, D.C. 1646580 1 14 10

North Branch Rock Creek near Norbeck, MD 1647720 29 17 25

North Branch Rock Creek near Rockville, MD 1647740 35 39 38

Northwest Branch Anacostia River near Colesville, MD 1650500 22 3 1

Hazel River at Rixeyville, VA 1663500 20 21 17

Rappahannock River at Remington, VA 1664000 17 23 20

Rapidan River near Culpeper, VA 1667500 18 24 16

Pamunkey River near Hanover, VA 1673000 21 41 41

James River at Buchanan, VA 2019500 13 34 28

James River at Scottsville, VA 2029000 8 26 23

James River at Cartersville, VA 2035000 10 35 36
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 27

 
28 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 29
30 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 5. Summary of sediment data for water years 1985 through 2001

[USGS daily refers to daily-load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data 

 from the River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

 mg/L, milligrams per liter]

Period of

record for

sediment 

collection

(water

year)

Annual

load

computation

sources Station name

Station

identification

number

Drainage

area

(square

miles)

Eastern Shore 

1985–2001 Estimator/ USGS daily

/RIM

Choptank River near Greensboro, MD 01491000 113

Susquehanna River 

1985–1996 Estimator Susquehanna River at Towanda, PA 1 01531500 7,797

1985–1996 USGS daily/Estimator Susquehanna River at Danville, PA 1 01540500 11,220

1985–1992 Estimator Young Womans Creek near Renovo, PA 01545600 46.0

1989–1996 Estimator West Branch Susquehanna River at Lewisburg, PA1 01553500 6,847

1988–1992 Estimator Raystown Branch Juniata River at Saxton, PA 01562000 756

1985–1996 Estimator Juniata River at Newport, PA 1 01567000 3,355

1985–1996 Estimator Sherman Creek at Shermans Dale, PA 1 01568000 200

1985–1991 Estimator Susquehanna River at Harrisburg, PA 1 01570500 24,100

1985–1989 Estimator Swatara Creek near Hershey, PA1 01573560 483

1985–1989 Estimator Codorus Creek near York, PA1 01575500 222

1985–1989 Estimator Codorus Creek at Pleasureville, PA 1 01575585 267

1985–1996 Estimator Susquehanna River at Marietta, PA 1 01576000 25,998

1985–1992 Estimator Little Conestoga Creek near Churchtown, PA 01576085 5.82

1993–1995 Estimator Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 54.0

1985–1998, 2001 Estimator Conestoga River at Conestoga, PA 1 01576754 470

1985–2001 Estimator/ USGS daily Susquehanna River at Conowingo, MD 01578310 27,100

1986, 1988–1991 Estimator Little Conestoga Creek site 3A near Morgantown, PA 0157608335 1.42

Patuxent River 

1986, 1990, 1993, 1995 Estimator Patuxent River near Unity, MD 01591000 34.8

1987, 1988, 1990 Estimator Little Patuxent River at Savage, MD 01594000 98.4

1985–2001 USGS daily/RIM Patuxent River near Bowie, MD 01594440 348

1989–1992 Estimator Hunting Creek near Huntingtown, MD 01594670 9.38

1986–1989, 1991, 

 1994–1996

Estimator Killpeck Creek at Huntersville, MD 01594710 9

Potomac River 

1993–1996 Estimator Conococheague Creek at Fairview, MD 01614500 494

1985–1992 USGS daily Potomac River at Point of Rocks, MD 01638500 9,651

1989–1995 Estimator/ USGS daily Monocacy River at Bridgeport, MD 01639000 173

1985–1992 USGS daily Monocacy River at Reichs Ford Bridge 

 near Frederick, MD

01643020 817

1985–20012 RIM data 2 Potomac River at Chain Bridge at Washington, D.C. 2 01646580 11,570

1997–1999 USGS daily Cedar Run at Route 646 near Aden, VA 01656120 175

1 USGS sediment samples were augmented with sediment data collected by Susquehanna River Basin Commission.

2 Discharge is measured at Potomac River near Washington D.C., Little Falls Pumping Station (01646500), 1.2 miles upstream of Chain Bridge.
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 31

 

Table 5. Summary of sediment data for water years 1985 through 2001

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data 

 from the River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

 mg/L, milligrams per liter]

Average

water year

sediment

load

(tons)

Average

water year

dischargeweighted

sediment

concentration

(mg/L)

Average

water year

sediment

yield

(tons per

square

mile)

Mean daily

discharge

for sediment

period

(cubic feet

per second)

Mean daily

discharge

for period

of record

(cubic feet

per second) Period of streamflow record

Difference

of study 

period

mean daily

discharge

to period

of record

(in percent)

Station

identification

number

2,310 17.3 20.4 135 132 1949–2002 2.3 01491000

808,000 77.3 104 10,600 10,600 1914–2001 1 0 01531500

778,000 54.5 69.3 14,500 15,300 1906–2001 1 -5.2 01540500

840 12.6 18.2 67.6 73.5 1966–2001 -8.1 01545600

352,000 33.4 51.4 10,700 10,800 1940–2001 11 -0.9 01553500

196,000 247 259 807 921.0 1912–2001 -12.4 01562000

110,000 26.2 33.0 4,280 4,300 1900–2001 1 -0.5 01567000

7,640 29.8 38.2 260.0 292.0 1930–2001 1 -11.0 01568000

765,000 25.3 31.8 30,700 34,200 1891–2001 1 -10.2 01570500

41,400 64.4 85.6 652 781 1976–2001 1 -16.5 01573560

14,400 81.8 64.6 178 223 1941–1996 1 -20.1 01575500

17,800 70.8 66.5 255 254 1985–1989 1 0.2 01575585

1,700,000 47.2 65.4 36,600 37,000 1932–2001 1 -1.1 01576000

6,100 1,044 1,050 5.9 7.3 1983–1995 -18.9 01576085

17,400 223 321 79 81 1993–1998 -1.5 01576540

81,800 133 173.9 625 640 1985–2001 1 -2.4 01576754

1,107,000 29.9 40.8 37,600 39,800 1968–2002 -5.5 01578310

470 391 331 1.2 1.1 1985–1991 10.9 0157608335

1,380 40.2 39.6 34.8 38.8 1945–2002 -10.2 01591000

10,200 111 104 94 109 1940–1958, 1976–1980, 

1986–2002

-13.9 01594000

23,000 66.0 66.2 355 367 1978–2002 -3.3 01594440

122 12.3 13.0 10.1 10.5 1989–1997 -4.2 01594670

304 84.9 32.4 3.6 3.9 1986–1997 -6.7 01594710

45,500 52.2 92 885 597 1929–1991, 1993–2002 48.2 01614500

1,128,000 136 117 8,430 9,440 1896–2002 -10.7 01638500

19,800 84.7 115 238 207 1943–2002 14.9 01639000

108,000 138 133 797 939 1943–2002 -15.1 01643020

1,844,000 157 159 11,900 11,300 2 1931–2002 5.3 01646580

11,500 64.9 66 179 179 1997–1999 0 01656120
32 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 5. Summary of sediment data for water years 1985 through 2001—Continued

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data 

 from the River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

 mg/L, milligrams per liter]

Period of

record for

sediment 

collection

(water

year)

Annual

load

computation

sources Station name

Station

identification

number

Drainage

area

(square

miles)

Rappahannock River 

1985–1993 USGS daily Rappahannock River at Remington,VA 01664000 620

1989–2001 RIM data Rappahannock River near Fredericksburg, VA* 01668000 1,596

Pamunkey River 

1990–2001 RIM data Pamunkey River near Hanover, VA* 01673000 1,081

Mattaponi River 

1991–2001 RIM data Mattaponi River near Beulahville, VA* 01674500 601

James River

1987–2001 Estimator/ RIM data James River at Cartersville, VA* 02035000 6,259

Appomattox River

1990–2001 RIM data Appomattox River at Matoaca, VA* 02041650 1,340

* Indicates total suspended solids used.
Summary of Sediment Loads, Yields, and Discharge-Weighted Sediment Concentration s 33

 

 

Table 5. Summary of sediment data for water years 1985 through 2001—Continued

[USGS daily refers to daily load sediment stations, Estimator is sediment data from the Estimator model, and RIM is sediment data 

 from the River Input Monitoring Stations. Water Year is from October 1 of the previous year to September 30 of the current year;

 mg/L, milligrams per liter]

Average

water year

sediment

load

(tons)

Average

water year

dischargeweighted

sediment

concentration

(mg/L)

Average

water year

sediment

yield

(tons per

square

mile)

Mean daily

discharge

for sediment

period

(cubic feet

per second)

Mean daily

discharge

for period

of record

(cubic feet

per second) Period of streamflow record

Difference

of study 

period

mean daily

discharge

to period

of record

(in percent)

Station

identification

number

96,800 152 156 645 693 1943–2001 -6.9 01664000

527,000 299 330 1,790 1,670 1908–2001 7.2 01668000

39,400 38.5 36.5 1,040 1,010 1942–2001 3.0 01673000

5,030 10.0 8.4 512 577 1942–1987, 1990–2001 -11.3 01674500

720,000 98.7 115 7,400 7,160 1900–2001 3.4 02035000

17,800 15.1 13.3 1,200 1,350 1970–2001 -11.1 02041650
34 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 6. Rankings of sediment loads, yields, and discharge-weighted sediment concentrations, from 

highest (1) to lowest (43) values, for stations operating from water years 1985 through 2001

Station name Station

identification

number

Suspendedsediment load

ranking

Sediment

yield

ranking

Dischargeweighted

sediment

concentration

ranking

Susquehanna River at Conowingo, MD 01578310 4 24 27

Susquehanna River at Marietta, PA 01576000 2 21 23

Susquehanna River at Harrisburg, PA 01570500 7 30 30

Susquehanna River at Danville, PA 01540500 6 17 21

Potomac River at Chain Bridge at Washington, D.C. 01646580 1 76

West Branch Susquehanna River at Lewisburg, PA 01553500 10 23 26

Susquehanna River at Towanda, PA 01531500 5 14 16

Potomac River at Point of Rocks, MD 01638500 3 10 9

James River at Cartersville, VA* 02035000 8 11 12

Juniata River at Newport, PA 01567000 12 28 29

Rappahannock River near Fredericksburg, VA* 01668000 9 33

Appomattox River at Matoaca, VA* 02041650 22 33 32

Pamunkey River near Hanover, VA* 01673000 18 27 25

Conococheague Creek at Fairview, MD 01614500 16 15 22

Raystown Branch Juniata River at Saxton, PA 01562000 11 5 4

Monocacy River at Reichs Ford Bridge near Frederick, MD 01643020 13 9 8

Swatara Creek near Hershey, PA 01573560 17 16 20

Rappahannock River at Remington, VA 01664000 14 8 7

Conestoga River at Conestoga, PA 01576754 15 6 10

Mattaponi River at Beulahville, VA* 01674500 29 35 35

Patuxent River near Bowie, MD 01594440 19 19 18

Sherman Creek at Shermans Dale, PA 01568000 27 26 28

Codorus Creek at Pleasureville, PA 01575585 21 18 17

Monocacy River at Bridgeport, MD 01639000 20 12 14

Cedar Run at Route 646 near Aden, VA 01656120 25 20 19

Codorus Creek near York, PA 01575500 24 22 15

Choptank River near Greensboro, MD 01491000 30 31 31

Little Patuxent River at Savage, MD 01594000 26 13 11

Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 23 4 5

Young Womans Creek near Renovo, PA 01545600 32 32 33

Patuxent River near Unity, MD 01591000 31 25 24

Hunting Creek near Huntingtown, MD 01594670 35 34 34

Little Conestoga Creek near Churchtown, PA 01576085 28 1 1

Killpeck Creek at Huntersville, MD 01594710 34 29 13

Little Conestoga Creek site 3A near Morgantown, PA 0157608335 33 2 2

* Indicates total suspended solids were collected at the station.
Instantaneous Suspended-Sediment Concentrations 35

Instantaneous Suspended-Sediment 

Concentrations

From October 1, 1984 through September 30, 2002, 51 

stations had at least 3 years of instantaneous suspendedsediment concentrations with at least 10 measurements in 

each year (fig. 9), totaling 25,572 instantaneous measurements of suspended sediment. No stations meeting these 

criteria were found in West Virginia or New York. Drainagearea sizes for the 51 stations ranged from 0.36 to over 

27,000 mi 2.

Seven of the 51 stations showed no statistical difference 

between the median mean-daily discharges on the days when 

suspended-sediment samples were collected and the median 

mean-daily discharge for the entire period of sediment 

record ( p-values greater than or equal to 0.05) (table 7). At 

42 of the remaining 44 stations, the median of mean-daily 

discharges was higher for the sample population (table 7).

The 10th, 50th, and 90th percentiles of suspended-sediment concentration were calculated for each station (figs. 

10 a–c, table 7). The five sediment stations with the highest 

suspended-sediment concentrations at the 10th percentile 

were for rivers draining to the Susquehanna River in 

Pennsylvania (Brush Run, site 2, near McSherrystown; 

Codorus Creek at Pleasureville; Conestoga River at 

Conestoga; and Little Conestoga Creek near Churchtown), 

and one station draining to the Potomac River in Virginia 

(Cannon Creek near Garrisonville) (fig. 10a, tables 7–8). 

The 10th percentile of suspended-sediment concentrations 

may reflect low-flow conditions. Three of the five sediment 

stations with the highest suspended-sediment concentration 

at the 50th percentile included the same stations in Pennsylvania as the 10th percentile (Conestoga River at Conestoga, 

Codorus Creek at Pleasureville, and Little Conestoga Creek 

near Churchtown), another station in Pennsylvania (Paxton 

Creek near Penbrook), and one station in Maryland draining 

to the Patuxent River (Killpeck Creek at Huntersville,

Maryland) (fig. 10b, tables 7–8). At the 90th percentile, the 

five highest suspended-sediment concentrations included 

four stations in Pennsylvania draining to the Susquehanna 

River (Bald Eagle Creek near Fawn Grove, Little Conestoga 

Creek near Churchtown, Mill Creek at Eshelman Mill Road 

near Lyndon, and Pequea Creek at Martic Forge), and 

the same station in Maryland with high sediment concentration at the 50th percentile, draining to the Patuxent River 

(Killpeck Creek at Huntersville, Maryland) (fig. 10c, tables 

7–8). The Little Conestoga Creek near Churchtown was the 

highest for the 10th, 50th, and 90th percentiles (figs. 10 a–c, 

tables 5 and 8). The lowest suspended-sediment concentration at the 10th, 50th, and 90th percentiles was at Bobs Creek 

near Pavia, Pennsylvania, in the Susquehanna River Basin, 

which drains close to 100 percent forested land (Langland 

and others, 1999) (figs. 10a–c, tables 5 and 8).

Sediment-Transport Curves

Suspended-sediment transport curves were generated for 

the 51 stations in the Chesapeake Bay Watershed with at 

least 3 complete years of data and at least 10 suspended-sediment samples in a given year (figs. 9, 11 a–e, and table 7). 

The least-squares regression coefficient generated for all 

plots ranges from 0.02 to 0.81 and averages 0.48 (figs. 11 a–

e, table 7). The scatter in the sediment-transport curves 

illustrates that one or more factors other than discharge are 

controlling suspended-sediment concentrations. The scatter 

in sediment-transport curves can be related to a number of 

factors including seasonality, land use, hysteresis, and natural climatic variability (Walling and Webb, 1982).

Normalizing instantaneous discharge by drainage area 

and plotting the transport curves by drainage-area classes 

(fig. 12) shows that for the larger drainage areas (classes A 

and B, see page 10), the best-fit lines plot close together 

(figs. 12 a–b), and have similar suspended-sediment concentrations with respect to the normalized discharge. The Susquehanna River at Conowingo, Maryland (Class A) and the 

West Branch Susquehanna River at Lewisburg, Pennsylvania 

(Class B) show the lowest suspended-sediment concentrations at higher normalized discharges (figs. 12 a–b). The 

graph of Class C rivers shows the Conestoga River at 

Conestoga, Pennsylvania, with high suspended-sediment 

concentrations at high normalized discharges (fig. 12c). The 

graph of Class D rivers shows two stations draining to the 

Susquehanna River with high suspended-sediment concentrations at median to high normalized discharges (Codorus 

Creek at Pleasureville, Pennsylvania, and Codorus Creek 

near York, Pennsylvania) (fig. 12d). The graph of Class E 

rivers shows Pequea Creek at Martic Forge, Pennsylvania, 

with the highest suspended-sediment concentrations at 

nearly all normalized discharges (fig. 12e). Pequea Creek is 

a tributary to the Susquehanna River. The graph of Class F 

rivers shows Mill Creek, a tributary to the Conestoga River, 

with the highest suspended-sediment concentrations at 

median to high discharges (fig. 12f). The graph of Class G 

rivers shows several rivers grouped together with high suspended-sediment concentrations at medium to high normalized discharges: Muddy Creek and Cannon Creek in the 

Potomac River Basin, and Cedar Run and Paxton Creek in 

the Susquehanna River Basin (fig. 12g). The lowest suspended-sediment concentrations for Class G rivers are at 

Bobs Creek near Pavia, Pennsylvania (fig. 12g). For Class 

H, five rivers plot close together and show high suspendedsediment concentrations at high normalized discharges in the 

Susquehanna River Basin (Little Conestoga Creek, Bald 

Eagle Creek, Big Spring Run, and an unnamed tributary to 

Big Spring Run, Pennsylvania) and Killpeck Creek near 

Huntersville, Maryland, in the Patuxent River Basin (fig. 12).

For five of the eight drainage area classes of rivers 

(Classes C, D, E, F, and H), five stations that drain to the 

Susquehanna River have the highest suspended-sediment 

concentrations at high discharges (Class C–Conestoga River, 

Class D–Codorus Creek, Class E–Pequea Creek, Class F–

Mill Creek, and Class H–Little Conestoga Creek). Three of 

the five stations drain to the Conestoga River in Pennsylvania (Little Conestoga Creek near Churchtown; Mill Creek at 

Eshelman Mill Road near Lyndon; and Conestoga River at 

Conestoga).
36 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 7. Summary of instantaneous suspended-sediment concentration data for stations used in this 

report for water years 1985 through 2002, including 10th, 50th, and 90th percentiles

[Wilcoxon P-value, sediment transport equation (slope, intercept, and regression coefficient), and drainage area class are also shown.

 The Mann-Whitney-Wilcoxon tests the difference between the mean-daily discharge on days of suspended-sediment samples versus the

 mean-daily discharge for the entire water years of sediment record. P-values less than 0.05 indicate the two populations are statistically

 different; mg/L, milligrams per liter, ft3/s, cubic feet per second; R2 -Pearson product-moment correlation coefficient]

Station name Station

identification

number

Years

of

record

Number

of

samples

Area

(square

miles)

10th percentile

suspendedsediment

concentration

( mg/L)

Eastern Shore 

Nassawango Creek near Snow Hill, MD 01485500 1999–2002 94 44.9 3

Nanticoke River near Bridgeville, DE 01487000 1994–2002 149 75.4 3

Choptank River near Greensboro, MD 01491000 1985–2002 502 113 2

Chesterville Branch near Crumpton, MD 01493112 1996–2002 92 6.12 5

Susquehanna River 

Susquehanna River at Towanda, PA 01531500 1985–1993 152 7,797 5

Susquehanna River at Danville, PA 01540500 1985–1995 492 11,220 7

West Branch Susquehanna River at Lewisburg, PA 01553500 1985–1995 443 6,847 2

East Mahantango Creek at Klingerstown, PA 01555400 1993–2000 89 44.7 4

Bobs Creek near Pavia, PA 01559795 1993–2000 61 16.6 1

Raystown Branch Juniata River at Saxton, PA 01562000 1985–1993 121 756 1

Juniata River at Newport, PA 01567000 1985–1995 215 3,354 3

Sherman Creek at Shermans Dale, PA 01568000 1985–1995 204 207 5

Conodoguinet Creek near Hogestown, PA 01570000 1985–2002 98 470 3

Susquehanna River at Harrisburg, PA 01570500 1985–1995 322 24,100 5

Paxton Creek near Penbrook, PA 01571000 1985–1994 425 11.2 6

Cedar Run at Eberlys Mill, PA 01571490 1993–1997 99 12.6 15

Swatara Creek near Hershey, PA 01573560 1985–1994 221 483 8

Brush Run Site 2 near McSherrystown, PA 01573810 1985–1991 985 0.38 19

West Conewago Creek near Manchester, PA 01574000 1985–1994 247 510 10

Codorus Creek near York, PA 01575500 1985–1990 203 222 10

Codorus Creek at Pleasureville, PA 01575585 1985–1994 431 267 19

Susquehanna River at Marietta, PA 01576000 1987–1994 245 25,990 8

Little Conestoga Creek near Churchtown, PA 01576085 1985–1995 1,104 5.82 53

Big Spring Run near Willow Street, PA 01576521 1993–2001 400 1.77 7

North Fork Unnamed Tributary to Big Spring Run at Lampeter, PA 01576527 1993–2001 354 0.36 5

Unnamed tributary to Big Spring Run near Lampeter, PA 01576529 1993–2001 415 1.42 4

Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 1992–1995 149 54.2 11

Conestoga River at Conestoga, PA 01576754 1985–1995 783 470 23

Pequea Creek at Martic Forge, PA 01576787 1985–1995 106 148 17

Bald Eagle Creek near Fawn Grove, PA 01577400 1986–1990 430 0.43 4.5

Susquehanna River at Conowingo, MD 01578310 1985–2002 660 27,100 5.5

Patuxent River 

Patuxent River near Unity, MD 01591000 1986-2000 410 34.8 2

Little Patuxent River at Savage, MD 01594000 1985-2000 454 98.4 2

Patuxent River near Bowie, MD 01594440 1985-2002 654 348 10

Western Branch at Upper Marlboro, MD 01594526 1986-2000 419 89.7 7

Hunting Creek near Huntingtown, MD 01594670 1986-1998 316 9.38 4

Killpeck Creek at Huntersville, MD 01594710 1986-1997 427 3.26 6
Instantaneous Suspended-Sediment Concentrations 37

 

Table 7. Summary of instantaneous suspended-sediment concentration data for stations used in this 

report for water years 1985 through 2002, including 10th, 50th, and 90th percentiles

[Wilcoxon P-value, sediment transport equation (slope, intercept, and regression coefficient), and drainage area class are also shown.

 The Mann-Whitney-Wilcoxon tests the difference between the mean daily discharge on days of suspended-sediment samples versus the

 mean daily discharge for the entire water years of sediment record. P-values geater than 0.05 indicate the two populations are statistically

 different; mg/L, milligrams per liter, ft3/s, cubic feet per second; R2 -Pearson product-moment correlation coefficient]

Sediment Transport Curve

50th percentile

suspendedsediment

concentration

( mg/L)

90th percentile

suspendedsediment

concentration

( mg/L)

Median

discharge

of

population

( ft 3 /s)

Median

discharge

of sample

( ft 3 /s)

MannWhitneyWilcoxon

P-value Slope Intercept

Regression

coefficient

 (R2 )

Drainage

area

class *

Station

identification

number

11 35 23 64 0 0.27 0.54 0.19 F 01485500

26 196 82 125 0 0.72 -0.16 0.24 F 01487000

10 47 82 150 0 0.61 -0.37 0.57 E 01491000

15 143 6 7 0 0.81 0.46 0.56 H 01493112

32 243 6,000 19,500 0 1.02 -2.78 0.67 B 01531500

20 140 9,115 19,500 0 0.91 -2.32 0.61 A 01540500

10 66 7,010 14,350 0 0.93 -2.70 0.63 B 01553500

8 96 32 27 0.559 0.49 0.33 0.40 F 01555400

3 8 9 13 0.692 0.22 0.33 0.15 G 01559795

8 34.5 410 400 0.197 0.75 -1.00 0.43 C 01562000

34 136 2,380 4,840 0 0.99 -2.28 0.61 B 01567000

24 210 143 309 0 0.83 -0.78 0.56 D 01568000

8 164 327 450 0.001 0.95 -1.53 0.66 C 01570000

25 138 21,000 39,700 0 0.95 -2.95 0.68 A 01570500

186 1,370 6 12 0 0.88 0.55 0.61 G 01571000

74 166 12 14 0.080 0.60 0.99 0.21 G 01571490

39 450 433 970 0 1.16 -1.85 0.68 C 01573560

105 617 0.03 1 0 0.29 1.92 0.16 H 01573810

63 397 286 777 0 0.73 -0.36 0.47 C 01574000

40 557 129 197 0 1.13 -1.07 0.63 D 01575500

189 733 193 329 0 1.18 -1.16 0.64 D 01575585

49 192 24,600 63,000 0 1.00 -3.10 0.70 A 01576000

548 3,140 4 10 0 0.90 1.30 0.62 H 01576085

74.5 840 2 3 0 1.09 1.36 0.32 H 01576521

49.5 611 0.2 0.7 0 0.46 1.96 0.13 H 01576527

39 643 1.1 1.4 0 1.04 1.52 0.36 H 01576529

117 2,090 47 69 0.002 1.41 -0.68 0.73 F 01576540

201 1,450 439 790 0 1.22 -1.67 0.66 C 01576754

184 2,070 138 204 0.012 1.52 -1.52 0.48 E 01576787

172.5 2,365 0.3 0.4 0 1.02 2.08 0.43 H 01577400

16 85 25,200 58,300 0 0.63 -1.77 0.55 A 01578310

24 496 26 85 0 0.82 -0.21 0.42 G 01591000

167.5 904 75 262 0 1.53 -1.92 0.81 E 01594000

42.5 217 222 444 0 0.72 -0.30 0.40 D 01594440

161 582 52 309 0 0.92 -0.20 0.67 F 01594526

23 85 7 33 0 0.43 0.69 0.34 G 01594670

267 1,520 3 15 0 1.19 0.74 0.68 H 01594710
38 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 7. Summary of instantaneous suspended-sediment concentration data for stations used in this 

report for water years 1985 through 2002, including 10th, 50th, and 90th percentiles—

Continued

Station name Station

identification

number

Years

of

record

Number

of

samples

Area

(square

miles)

10th percentile

suspendedsediment

concentration

( mg/L)

Potomac River 

Conococheague Creek at Fairview, MD 01614500 1985–2001 397 494 7

Muddy Creek at Mount Clinton, VA 01621050 1993–2001 74 14.2 4

South Fork Shenandoah River at Front Royal, VA 01631000 1985–2001 120 1,642 2

North Fork Shenandoah River near Strasburg, VA 01634000 1985–2001 112 768 2

Monocacy River at Bridgeport, MD 01639000 1985–1996 132 173 4

Potomac River at Chain Bridge at Washington, D.C. 01646580 1985–2002 177 11,570 3

Accotink Creek near Annandale, VA 01654000 1985–2001 50 23.5 2

Cedar Run near Aden, VA 01656100 1985–1988,

1996–1999

1,502 155 5

Cedar Run at Route 646 near Aden, VA 01656120 1996–2000 1,854 175 6

South Fork Quantico Creek near Independent Hill, VA 01658500 1985–2001 3,331 7.64 5

Cannon Creek near Garrisonville, VA 01660380 1994–1997 441 10.2 18

Beaverdam Run near Garrisonville, VA 01660500 1997–2001 1,194 12.7 9

Pamunkey River 

Pamunkey River near Hanover, VA 01673000 1985–2001 120 1,081 3

Mattaponi River

Mattaponi River near Beulahville, VA 01674500 1985–1988,

1989–2001

113 601 3
Instantaneous Suspended-Sediment Concentrations 39

 

Table 7. Summary of instantaneous suspended-sediment concentration data for stations used in this 

report for water years 1985 through 2002, including 10th, 50th, and 90th percentiles—

Continued

Sediment Transport Curve

50th percentile

suspendedsediment

concentration

( mg/L)

90th percentile

suspendedsediment

concentration

( mg/L)

Median

discharge

of

population

( ft 3 /s)

Median

discharge

of sample

( ft 3 /s)

MannWhitneyWilcoxon

P-value Slope Intercept

Regression

coefficient

 (R2 )

Drainage

area

class *

Station

identification

number

81 365 350 2,230 0 0.83 -0.87 0.47 C 01614500

20.5 165 5 5 0.797 0.81 0.77 0.35 G 01621050

10.5 157 987 1,600 0 1.18 -2.77 0.70 B 01631000

13 215 315 789 0 1.07 -1.91 0.68 C 01634000

74 460 75 565 0 0.55 0.24 0.55 E 01639000

11 170 27,700 41,900 0.802 0.87 -2.11 0.57 A 01646580

5 27 10 8 0.181 0.17 0.63 0.02 G 01654000

16 86 69 171 0 0.29 0.66 0.40 E 01656100

19 95 146 165 0.216 0.27 0.77 0.32 E 01656120

18 160 4 6 0 0.36 1.05 0.31 H 01658500

150 617 12 42 0 1.00 0.43 0.54 G 01660380

25 82 5 7 0 0.17 1.27 0.06 G 01660500

10 71.5 510 651 0.036 0.78 -1.01 0.58 B 01673000

8 27 315 425 0.050 0.46 -0.24 0.45 C 01674500

* Class A > 25,000–70,200 km 2 (square kilometers) > 9,650–27,100 mi 2 (square miles) 

 Class B > 2,500–25,000 km 2 > 965–9,650 mi 2

 Class C > 1,000–2,500 km 2 > 386–965 mi 2

 Class D > 500–1,000 km 2 > 193–386 mi 2

 Class E > 250–500 km 2 > 96.5–193 mi 2

 Class F > 100–250 km 2 > 38.6–96.5 mi 2

 Class G > 20–100 km 2 > 7.70–38.6 mi 2 

 Class H > 0.93–20 km 2 0.36–7.70 mi 2
40 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 41
42 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 43
44 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

 

Table 8. Rankings of 10th, 50th, and 90th percentiles of suspended-sediment concentrations 

 from highest (1) to lowest (51) values

Station name Station

identification

number

Rank

10th

percentile

Rank 

50th

percentile

Rank

90th

percentile

Nassawango Creek near Snow Hill, MD 01485500 36 40 47

Nanticoke River near Bridgeville, DE 01487000 36 26 26

Choptank River near Greensboro, MD 01491000 43 43 46

Chesterville Branch near Crumpton, MD 01493112 23 38 34

Susquehanna River at Towanda, PA 01531500 23 25 22

Susquehanna River at Danville, PA 01540500 15 33 35

West Branch Susquehanna River at Lewisburg, PA 01553500 43 43 45

East Mahantango Creek at Klingerstown, PA 01555400 32 46 38

Bobs Creek near Pavia, PA 01559795 50 51 51

Raystown Branch Juniata River at Saxton, PA 01562000 50 46 48

Juniata River at Newport, PA 01567000 36 24 37

Sherman Creek at Shermans Dale, PA 01568000 23 29 25

Conodoguinet Creek near Hogestown, PA 01570000 36 46 31

Susquehanna River at Harrisburg, PA 01570500 23 27 36

Paxton Creek near Penbrook, PA 01571000 19 5 7

Cedar Run at Eberlys Mill, PA 01571490 7 15 29

Swatara Creek near Hershey, PA 01573560 13 22 19

Brush Run Site 2 near McSherrystown, PA 01573810 3 12 12

West Conewago Creek near Manchester, PA 01574000 9 17 20

Codorus Creek near York, PA 01575500 9 21 16

Codorus Creek at Pleasureville, PA 01575585 3 4 10

Susquehanna River at Marietta, PA 01576000 13 19 27

Little Conestoga Creek near Churchtown, PA 01576085 1 1 1

Big Spring Run near Willow Street, PA 01576521 15 14 9

North Fork Unnamed Tributary to Big Spring Run at Lampeter, PA 01576527 23 18 14

Unnamed Tributary to Big Spring Run near Lampeter, PA 01576529 32 22 11

Mill Creek at Eshelman Mill Road near Lyndon, PA 01576540 8 11 3

Conestoga River at Conestoga, PA 01576754 2 3 6

Pequea Creek at Martic Forge, PA 01576787 6 6 4

Bald Eagle Creek near Fawn Grove, PA 01577400 31 7 2

Susquehanna River at Conowingo, MD 01578310 22 36 41

Patuxent River near Unity, MD 01591000 43 29 17

Little Patuxent River at Savage, MD 01594000 43 8 8

Patuxent River near Bowie, MD 01594440 9 20 23

Western Branch at Upper Marlboro, MD 01594526 15 9 15

Hunting Creek near Huntingtown, MD 01594670 32 31 41

Killpeck Creek at Huntersville, MD 01594710 19 2 5

Conococheague Creek at Fairview, MD 01614500 15 13 21

Muddy Creek at Mount Clinton, VA 01621050 32 32 30

South Fork Shenandoah River at Front Royal, VA 01631000 43 42 33

North Fork Shenandoah River near Strasburg, VA 01634000 43 39 24

Monocacy River at Bridgeport, MD 01639000 32 15 18

Potomac River at Chain Bridge at Washington, D.C. 01646580 36 40 28

Accotink Creek near Annandale, VA 01654000 43 50 49

Cedar Run near Aden, VA 01656100 23 36 40

Cedar Run at Route 646 near Aden, VA 01656120 19 34 39

South Fork Quantico Creek near Independent Hill, VA 01658500 23 35 32

Cannon Creek near Garrisonville, VA 01660380 5 10 12

Beaverdam Run near Garrisonville, VA 01660500 12 27 43

Pamunkey River near Hanover, VA 01673000 36 43 44

Mattaponi River near Beulahville, VA 01674500 36 46 49
Instantaneous Suspended-Sediment Concentrations 45

 
46 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 47
48 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 49
50 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 51
52 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 53
54 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Instantaneous Suspended-Sediment Concentrations 55
56 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002
Summary and Conclusions 57

Summary and Conclusions

Much of the habitat in the Chesapeake Bay Watershed is 

degraded because of sediment. Determining potential 

source areas of sediment in the Watershed is an important 

component in reduction of erosion and sediment transport. 

This report describes historical annual suspended-sediment 

loads, yields, and discharge-weighted concentrations, and 

instantaneous suspended-sediment concentrations compiled 

from 65 stations operating from 1952–2002 in the 64,000-

square-mile Chesapeake Bay Watershed. Suspended-sediment load, yield, and discharge-weighted sediment concentration data were separated into two periods, 1952–84 and 

1985–2001. In 1985, the Chesapeake Bay Program began 

recommending sediment regulations, so 1985 represents an 

important break in the data. The size of drainage areas for 

sediment stations where annual suspended-sediment loads 

were collected ranged from 0.36 to 27,100 square miles. 

Areas draining 100 to 500 square miles had the most sediment stations operating at any time, and areas draining 50 to 

100 square miles had the least sediment stations operating 

from 1952 through 2001. Suspended-sediment load data 

compiled for this report were typically computed using two 

methods, the subdivision method, which was used at dailyload stations, and the linear-regression or ESTIMATOR 

method, which was used to compute monthly and annual 

loads. A comparison of both methods for nine stations totaling 36 years of record indicates that the ESTIMATOR 

method has a tendency to compute higher suspended-sediment loads than the subdivision method.

Average annual suspended-sediment loads are strongly, 

positively correlated to both drainage area (R2 = 0.88) and 

average annual mean-daily discharge (R2 = 0.88) for the sediment-collection period (1952–2001). Size of the drainage 

area shows a weak, inverse relation to both average annual 

sediment yield (R2 = -0.17) and average annual dischargeweighted sediment concentration (R2 = -0.17). This inverse 

relation is expected as more sediment storage sites become 

available as drainage-area size increases.

The Chesapeake Bay River Input Monitoring Program 

was established in the mid–1980s to quantify loads and longterm trends in suspended sediment entering the tidal part of 

the Chesapeake Bay Basin from its nine major tributaries 

(Appomattox, Choptank, James, Mattaponi, Pamunkey, 

Patuxent, Potomac, Rappahannock, and Susquehanna). The 

nine River Input Monitoring stations drain 78 percent of the 

Chesapeake Bay Watershed, and the data collected at these 

stations allowed suspended-sediment transport analysis at a 

large scale. The River Input Monitoring station data for 

1985 through 2001 indicated that the Potomac and 

Susquehanna Rivers had the highest average annual suspended-sediment loads. The Rappahannock and Potomac 

Rivers had the highest average annual sediment yields and 

discharge-weighted sediment concentrations. The Choptank, Mattaponi, and Appomattox Rivers had the three lowest average annual sediment loads, sediment yields, and 

discharge-weighted sediment concentrations.

For stations operating from 1952–84 (n = 43), two of the 

five highest suspended-sediment loads were on the Potomac 

River (Chain Bridge at Washington, D.C. and at Point of 

Rocks, Maryland). Three of the five highest average annual 

suspended-sediment loads from 1952–84 were for stations 

on the Susquehanna River (at Harrisburg, Pennsylvania; at 

Sunbury, Pennsylvania; and at Conowingo, Maryland). The 

highest average annual suspended-sediment loads were for 

rivers that drain the largest area. The sediment load at the 

Susquehanna River at Conowingo is affected by three 

upstream reservoirs that reduce the delivery of sediment to 

this station; if the reservoirs were not in place, the average 

annual suspended-sediment loads would likely be higher.

Similar rankings were produced by normalizing average 

annual suspended-sediment loads by drainage area to produce an average annual sediment yield and normalizing each 

annual suspended-sediment load by annual runoff to produce 

an average annual discharge-weighted sediment concentration. The similarity in ranking is because runoff is highly 

correlated to drainage area. The highest sediment yields and 

discharge-weighted sediment concentrations from 1952–84 

were for streams draining the suburban Washington, D.C. 

area (Snakeden Branch at Reston, Virginia; Smilax Branch at 

Reston, Virginia; and Northwest Branch Anacostia River 

near Colesville, Maryland). The lowest average annual sediment yields and discharge-weighted sediment concentrations 

for stations with data collected through 1984 were at Young 

Womans Creek near Renovo, Pennsylvania; Choptank River 

near Greensboro, Maryland; and the Pamunkey River near 

Hanover, Virginia. The high sediment yields for streams 

draining the metropolitan Washington, D.C. region may 

reflect urbanization and construction practices that were 

occurring in these basins when the stations were operating 

(1963–78).

 At stations operating from 1985 through 2001 (n = 35), 

four of the five highest average suspended-sediment loads 

were the same as for stations operating from 1952–84 

(Potomac River at Chain Bridge at Washington, D.C.; 

Potomac River at Point of Rocks, Maryland; Susquehanna 

River at Marietta, Pennsylvania; and Susquehanna River at 

Conowingo, Maryland). Four of the six highest average 

annual sediment yields and discharge-weighted sediment 

concentrations for the period 1985–2001 were for stations in 

Lancaster County, Pennsylvania, draining to the Conestoga 

River, a tributary to the Susquehanna River (Conestoga 

River at Conestoga, Pennsylvania; Little Conestoga Creek 

near Churchtown, Pennsylvania; Little Conestoga Creek site 

3A, near Morgantown, Pennsylvania; and Mill Creek at 

Eshelman Mill Road near Lyndon, Pennsylvania). The 

Rappahannock River near Fredericksburg, Virginia, had the 

third highest average annual sediment yield and dischargeweighted sediment concentration, and Raystown Branch 

Juniata River at Saxton, Pennsylvania, a tributary of the 

Susquehanna River, had the fifth highest average annual 

sediment yield and discharge-weighted sediment concentration.

Percentiles of suspended sediment (10th, 50th, and 90th) 
58 Summary of Suspended-Sediment Data for Streams Draining the Chesapeake Bay Watershed, Water Years 1952–2002

were examined for 51 stations with at least 3 years of data 

and at least 10 samples in a given year. The four highest 

suspended-sediment concentrations at the 10th percentile 

(ranging from 18 to 53 milligrams per liter) were in rivers 

draining to the Susquehanna River in Pennsylvania 

(Brush Run, site 2, near McSherrystown; Codorus Creek 

at Pleasureville; Conestoga River at Conestoga; and Little 

Conestoga Creek near Churchtown. The 10th percentile of 

suspended-sediment concentration reflects low-flow conditions. Three of the five sediment stations with the highest 

50th percentile of suspended-sediment concentration (ranging from 186 to 548 milligrams per liter) included the same 

stations in the Susquehanna River Basin as at the 10th percentile (Codorus Creek at Pleasureville; Conestoga River at 

Conestoga; and Little Conestoga Creek near Churchtown), 

another station in Pennsylvania (Paxton Creek near Penbrook), and one station in Maryland draining to the Patuxent 

River (Killpeck Creek at Huntersville, Maryland). At the 

90th percentile, the five highest suspended-sediment concentrations (ranging from 1,520 to 3,140 milligrams per liter) 

were for stations draining the Susquehanna River Basin in 

Pennsylvania (Little Conestoga Creek near Churchtown; 

Pequea Creek at Martic Forge; Bald Eagle Creek near Fawn 

Grove; and Mill Creek at Eshelman Mill Road near Lyndon) 

and Killpeck Creek at Huntersville, Maryland, in the 

Patuxent River Basin.

Sediment-transport curves generated for eight 

classes of drainage areas for 51 stations show that the

Susquehanna River Basin had the highest suspendedsediment concentrations in five of the eight classes:

 • Class C [>386–965 square miles]—Conestoga River, 

 • Class D [>193–386 square miles]—Codorus Creek, 

 • Class E [>96.5–193 square miles] Pequea Creek, 

 • Class F [>38.6–96.5 square miles]—Mill Creek, and 

 • Class H [0.36-7.70 square miles]—Little Conestoga

 Creek. 

Three of these five stations drain to the Conestoga River 

(Little Conestoga Creek near Churchtown, Pennsylvania; 

Mill Creek near Eshelman Mill Road near Lyndon, Pennsylvania; and Conestoga River at Conestoga, Pennsylvania). 

Cannon Creek near Garrisonville, Virginia, showed the highest suspended-sediment concentrations at high discharges for 

Class G (>7.70-38.6 square miles).

Suspended-sediment loads are highly correlated with 

area, and therefore, rankings of loads for stations in the 

Chesapeake Bay Watershed will reflect drainage-area size. 

Normalizing suspended-sediment loads by drainage area and 

annual runoff provides additional information on erosion and 

sediment delivery in each basin. In general, the highest average annual sediment yields were in rivers draining to the 

Susquehanna River. In the Susquehanna River Basin, the 

highest sediment yields and discharge-weighted sediment 

concentrations were in the Conestoga River Basin. The 

Conestoga River Basin drains primarily agricultural areas, 

but other sources of sediment, such as from bank erosion, 

also may be important in this basin.

References Cited

American Society for Testing and Materials (ASTM), 

1999, D 3977-97, Standard test method for determining 

sediment concentration in water samples: Annual Book 

of Standards Water and Environmental Technology, 

1999, Volume 11.02, p. 389–394.

Belval, D.L., and Sprague, L.A., 1999, Monitoring 

nutrients in the major rivers draining to Chesapeake Bay: 

U.S. Geological Survey Water-Resources Investigations 

Report 99–4238, 8 p.

Brown, L., Pavich, M.J., Hickman, R.E., Klein, J., and 

Middleton, R., 1988, Erosion of the eastern United 

States observed with 10Be: Earth Surface Processes and 

Landforms, v. 13, p. 441–457.

Cohn, T.A., Caulder, D.L., Gilroy, E.J., Zynjuk, L.D., and 

Summers, R.M., 1992, The validity of a simple 

statistical model for estimating fluvial constituent loads: 

An empirical study involving nutrient loads entering 

Chesapeake Bay: Water Resources Research, v. 289,

no. 9, p. 2,353–2,363.

Cohn, T.A., DeLong, L.L., Gilroy, E.J., Hirsh, R.M., and 

Wells, D.K., 1989, Estimating constituent loads:

Water Resources Research, v. 25, no. 5, p. 937–942.

Darrell, L.C., Majedi, B.F., Lizarraga, J.S., and 

Blomquist, J.D., 1999, Nutrient and suspendedsediment concentrations, trends, loads, and yields from 

the nontidal part of the Susquehanna, Potomac, Patuxent, 

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