Total Nutrient and Sediment Loads, Trends, Yields, and 

Nontidal Water-Quality Indicators for Selected Nontidal 

Stations, Chesapeake Bay Watershed, 1985–2011

New York

Pennsylvania

Maryland

West Virginia

Virginia

Delaware

Chesapeake Bay

Watershed

Open-File Report 2013–1052

U.S. Department of the Interior

U.S. Geological Survey

Total Nutrient and Sediment Loads, 

Trends, Yields, and Nontidal Water-Quality 

Indicators for Selected Nontidal Stations, 

Chesapeake Bay Watershed, 1985–2011

By Michael J. Langland, Joel D. Blomquist, Douglas L. Moyer, Kenneth E. Hyer, 

and Jeffrey G. Chanat

Open-File Report 2013–1052

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

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Suggested citation:

Langland, M.J., Blomquist, J.D., Moyer, D.L., Hyer, K.E., and Chanat, J.G., 2013, Total nutrient and sediment loads, 

trends, yields, and nontidal water-quality indicators for selected nontidal stations, Chesapeake Bay Watershed, 

1985–2011: U.S. Geological Survey Open-File Report 2013-1052, 51 p.
iii

Contents

Abstract...........................................................................................................................................................2

Introduction.....................................................................................................................................................3

Flow-adjusted Concentrations..................................................................................................................14

Combined Water-Quality Indicator...........................................................................................................34

Summary........................................................................................................................................................40

References Cited..........................................................................................................................................42

Appendix 1. Supplemental Data—Long-term Trends ............................................................................44

Appendix 2. Supplemental Data—10-year Trends .................................................................................47

Appendix 3. Supplemental Data—5-year Annual-Average Yields ......................................................50

Figures

1. Map showing the locations of long-term monitoring stations ..............................................7

2. Map showing the locations of all stations, 2011......................................................................8

3. Graph showing annual mean streamflow to the Chesapeake Bay, 1935–2011................11

4. Graphs showing annual mean streamflow for the Susquehanna River at 

Conowingo, Md., the Potomac River at Chain Bridge, Md., and the James River 

at Richmond, Va.,1985–2011 ......................................................................................................13

5. Graph showing annual combined total nitrogen load and mean streamflow for

the Chesapeake Bay River Input Monitoring (RIM) stations, 1990–2011...........................15

6. Graph showing annual combined total phosphorus load and mean streamflow for 

the Chesapeake Bay River Input Monitoring (RIM) stations, 1990–2011...........................17

7. Graph showing annual combined sediment load and mean streamflow for the

Chesapeake Bay River Input Monitoring (RIM) stations, 1990–2011 .................................19

8. Map showing total nitrogen flow-adjusted long-term trends, 1985–2011.........................22

9. Map showing total phosphorus flow-adjusted long-term trends, 1985–2011...................24

10. Map showing total sediment flow-adjusted long-term trends, 1985–2011 .......................26

11. Maps showing total nitrogen 10-year concentration trends (A) and

5-year yields (B)..........................................................................................................................31

12. Maps showing total phosphorus 10-year concentration trends (A) and 

5-year yields (B)..........................................................................................................................32

13. Maps showing sediment concentration 10-year trends (A) and

5-year yields (B)..........................................................................................................................33

14. Map showing total nitrogen combined indicator yields, 2006–2010 ..................................35

15. Map showing total phosphorus combined indicator yields, 2006–2010 ............................36

16. Map showing sediment combined indicator yields, 2006–2010..........................................37
iv

Tables

1. Description of data for the Chesapeake Bay Watershed ......................................................6

2. Station information for the 81 stations in the Chesapeake Bay Nontidal

Monitoring Network .....................................................................................................................9

3. Water-quality indicator summary ............................................................................................39
Total Nutrient and Sediment 

Loads, Trends, Yields, and 

Nontidal Water-Quality 

Indicators for Selected Nontidal 

Stations, Chesapeake Bay 

Watershed, 1985-2011
Abstract

The U.S. Geological Survey, in cooperation with Chesapeake Bay Program 

(CBP) partners, routinely reports long-term concentration trends and monthly 

and annual constituent loads for stream water-quality monitoring stations across 

the Chesapeake Bay watershed. This report documents flow-adjusted trends in 

sediment and total nitrogen and phosphorus concentrations for 31 stations in the 

years 1985-2011 and for 32 stations in the years 2002-2011. Sediment and total 

nitrogen and phosphorus yields for 65 stations are presented for the years 2006-

2011. A combined nontidal water-quality indicator (based on both trends and 

yields) indicates there are more stations classified as “improving water-quality 

trend and a low yield” than “degrading water-quality trend and a high yield” for 

total nitrogen. The same type of 2-way classification for total phosphorus and 

sediment results in equal numbers of stations in each indicator class. 
Introduction

The Chesapeake Bay has been adversely affected by nutrient and sediment 

enrichment. In 2010, the U.S. Environmental Protection Agency (USEPA) 

established a Total Maximum Daily Load (TMDL) requiring all jurisdictions in the 

Bay watershed to develop and implement Watershed Implementation Plans (WIPs) 

to reduce the loads of nutrients and sediment entering the Bay to established levels 

by 2025.

To consistently monitor and track loads, the Chesapeake Bay Program (CBP) 

partners formalized the CBP Nontidal Water-Quality Network (U.S. Environmental 

Protection Agency, 2004). Common sampling frequencies, protocols, and 

constituent analyses were established for all surface-water (stream) stations in the 

network. The U.S. Geological Survey in cooperation with the USEPA; and the 

States of New York, Pennsylvania, Maryland, Delaware, Virginia, and West 

Virginia; river basin commissions; and other partners, have expanded from 35 

stations in 2004 to the current network of 120 stations in 2012. 

To help track progress in meeting load-reduction goals, the USGS routinely reports 

long-term concentration trends and monthly and annual constituent loads for stream 

water-quality monitoring stations across the Chesapeake Bay watershed. 
Purpose and Scope

This report presents updated results of load and trend analyses for nutrients 

and sediment at stream stations in the Chesapeake Bay Nontidal WaterQuality Network (CB-NTN) for multiple time periods. Loads and trends in 

flow-adjusted concentrations were estimated for the long-term (1985-2011) 

and 10-year (2002-2011) periods; loads were estimated for the 5-year 

(2006-2011) period. Yields were estimated for the 5-year period and 

combined with trend results from the 10-year period to develop nontidal 

water-quality indicators.

Methods

In 2004, new analytical techniques were developed based on the USGS 

ESTIMATOR model (Cohn and others, 1989) and since that time have been 

used to estimate trends in streamflow, load, and flow-adjusted 

concentration (Langland and others, 2006). In 2012, additional changes 

were incorporated into the model to obtain results for 1985-2010 (Langland 

and others, 2012). 
All data and results available at 

http://cbrim.er.usgs.gov/
Monitoring Program Station Selection

 Table 1. Description of data for the Chesapeake Bay Watershed. 

 [Primary (P) stations were sampled monthly and during eight targeted 

storms per year (since 2006). Secondary (S) stations were sampled monthly]

Time 

period 

Length of 

record 

Type/analysis Number of 

stations 

(running total)

1985-2011 27 years P -loads/trends/yields 31

2002-2011 10 years P - load/trends/yields 1 (32) 

2007-2011 5 years P- loads/yields 33 (65) 

2002-2011 10 years S - trends 16 (81) 

Why are we examining multiple time periods?

- Align with current and historical data collection efforts (long-term and 

10-year loads and trends, 5-year loads)

- Examine changes over shorter time frames (since early 2000’s)

- Provide additional data for indicators and measures of change
Long

-Term Monitoring 

Stations

The USGS is currently 

updating load and trend data at 

31 long-term (generally 1985-

2011) stations in the Bay 

watershed (fig. 1). The 31 

stations consist of : 

9 monitoring stations (red 

circles) at or near the most 

downstream nontidal areas of 

many large river basins and are 

termed “River Input 

Monitoring (RIM) Stations.”

22 upstream stations (black 

circles) operated by multiple 

agencies

Figure 1

Long-term 

stations
Monitoring Stations

The locations of all 81 stations 

evaluated for loads and (or) 

trends in 2011 are shown in 

figure 2. • The red and black circles 

represent the 31 long-term 

monitoring stations. 

• The yellow circle represents 

the one new site with 10 or 

more years of record added 

in 2011. 

• The 33 blue circles 

represent stations with 5-9 

years of record. 

• The 16 brown squares 

represent secondary stations 

with 10 years of record. 

Figure 2

All stations, 2011
Table 2. Station information for the 81 stations in the Chesapeake Bay Nontidal 

Monitoring Network.

USGS GAGE Multi-collector station name Station Name Years 

active

Drainage Area 

(square miles) Latitude Longitude

These 31 indicator stations have trends for long-term, 10 years, and 5 year yields 

01531500 WQN0305 Susquehanna River at Towanda, Pa. 27 7,797 414555 762628 

01536500 WQN0302 Susquehanna River at Wilkes-Barre, Pa. 27 9,960 411503 755252 

01540500 WQN0301 Susquehanna River at Danville, Pa. 27 11,220 405729 763710 

01553500 WQN0401 West Branch Susquehanna River at Lewisburg, Pa. 27 6,859 405803 765236 

01567000 WQN0214 Juniata River at Newport, Pa. 27 3,354 402842 770746 

01576000 WQN0201 Susquehanna River at Marietta, Pa. 25 25,990 400316 763152 

01576754 WQN0273 Conestoga River at Conestoga, Pa. 27 470 395647 762205 

01578310 01578310 Susquehanna River at Conowingo, Md. 27 27,100 393928 761029 

01491000 01491000 Choptank River near Greensboro, Md. 27 113 385950 754710 

01582500 GUN0258 Gunpowder Falls at Glencoe, Md 27 160 393302 763809 

01586000 NPA0165 North Branch Patapsco River at Cedarhurst, Md. 27 56.6 393000 765300 

01591000 PXT0972 Patuxent River near Unity, Md 27 34.8 391418 770321 

01594440 01594440 Patuxent River near Bowie, Md. 27 348 385721 764136 

01599000 GEO0009 Georges Creek near Franklin, Md. 27 72.4 392938 790241 

01601500 WIL0013 Wills Creek near Cumberland, Md. 27 247 393941 784650 

01614500 CONO0180 / WQN0501 Conococheague Creek at Fairview, Md. 27 501 394256 774931 

01619500 ANT0044, ANT0047 Antietem Creek near Sharpsburg, Md. 27 281 392701 774352 

01631000 1BSSF003.56 S F Shenandoah River at Front Royal, Va. 27 1,642 385449 781240 

01634000 1BNFS010.34 N F Shenandoah River near Strasburg, Va. 27 768 385836 782011 

01637500 CAC0148 Catoctin Creek near Middletown, Md 27 66.9 392538 773322 

01639000 MON0528 / MON0546 Monocacy River at Bridgeport, Md. 27 173 394043 771406 

01646580 01646580 Potomac River at Chain Bridge, Md. 27 11,600 385546 770701 

01651000 ANA0082, A4 NW Branch Anaacostia River nr Hyattsville, Md. 27 49.4 385708 765778 

01668000 - Rappahannock River near Fredericksburg, Va. 24 1,596 381920 773105 

01671020 8-NAR005.42 North Anna at Hart Corner near Doswel, Va. 27 463 375100 772541 

01673000 - Pamunkey River near Hanover, Va. 24 1,081 374603 771957 

01674500 - Mattaponi River near Beulahville, Va. 24 601 375316 770948 

02035000 - James River at Cartersville, Va. 25 6,257 374015 780510 

02037500 2-JMS117.35 / 2-JMS113.20 James River at Richmond, Va. 27 6,758 373347 773250 

02041650 - Appomattox River at Matoaca, Va. 24 1,344 371330 772832 

02042500 2-CHK035.26 Chickahominy River near Providence Forge, Va 27 252 372610 770340 

This 1 indicator stations has trends for 10 years and yields for 5 years 

27 32.5

 

392045 

 

01589300 GWN0115 Gwynns Falls at Villa Nova, Md 764359 

These 33 indicator stations have 5 year yields 

01515000 01515000 Susquehanna River near Waverly, NY 6 4,773 415905 763005 

01531000 01531000 Chemaung River at Chemung, NY 6 2,506 420008 763806 

01542500 01542500 WB Susquehanna River at Karthaus, Pa 6 1,462 410703 780633 

01555000 WQN0229 Penns Creek at Penns Creek, Pa 6 301 405200 770255 

01562000 WQN0223 Raystown Branch Juniata River at Saxton, Pa 6 756 401257 781556 

01568000 WQN0243 Sherman Creek at Shermans Dale, Pa 6 200 401924 771009 

01570000 WQN0271 Conodoguinet Creek near Hogestown, Pa 6 470 401508 770117 

01571500 WQN0212 / 01571505 Yellow Breeches Creek near Camp Hill, Pa 6 216 401329 765354 

01573560 WQN0272 Swatara Creek near Hershey, Pa 6 483 401754 764005 

01574000 WQN0210 West Coneago Creek near Manchester, Pa 6 510 400456 764313 

01576787 WQN0204 Pequea Creek near MarticForge, Pa 6 148 395421 791943 

01667500 3-RAP030.21 / 01667500 Rapidan River near Culpeper, Va 6 472 382132 775824 

01487000 - Nanticoke River Near Bridgeville, De 6 75.4 384345 753341 
USGS GAGE Multi-collector station name Station Name Years 

active

Drainage Area 

(square miles) Latitude Longitude

01491500 TUK0181 Tuckahoe Creek Near Ruthsburg, Md 6 85.2 385802 755635 

01495000 BEL0053 Big Elk Creek At Elk Mills, Md 6 52.6 393644 754901 

01502500 - Unadilla River At Rockdale, NY 6 520 422240 752423 

01503000 - Susquehanna River At Conklin, NY 6 2232 420207 754812 

01529500 - Cohocton River Near Campbell NY 6 470 421509 771301 

01549760 WQN0410 West Branch Susquehanna River Near Jersey Shore 6 5225 411659 771920 

01578475 WQN0263 Octoraro Creek At Richardsmere, Md 6 177 394125 760741 

01580520 DER0015 Deer Creek Near Darlington, Md 6 164 393725 760953 

01594526 TF1.2 Western Branch At Upper Marlboro. Md 6 89.7 384851 764503 

01604500 - Patterson Creek Near Headsville, Wv 6 221 392635 784920 

01608500 - South Branch Potomac River Near Springfield, Wva 6 1461 392649 783916 

01610155 WQN0512 Sideling Hill Creek Near Bellegrove, Md 6 102 393858 782039 

01611500 - Cacapon River Near Great Cacapon, Wva 6 675 393456 781836 

01613095 WQN0510 Tonoloway Creek Near Hancock, Md 6 111 394223 780910 

01613525 WQN0509 Licking Creek Near Pectonville, Md 6 193 394040 780212 

01616500 - Opequon Creek Near Martinsburg, Wva 6 272 392525 775620 

01619000 WQN0511 Antietam Creek Near Waynesboro, Pa 6 93.5 394260 773629 

02024752 2-JMS279.41 James River At Blue Ridge Pkwy Bridge Nr Big Island, Va 6 3076 373320 792201 

01609000 WQN0513 Town Creek Near Oldtown, Md 6 148 393312 783318 

These 16 Secondary stations have 10 year trends 

01626000 1BSTH027.85 South River neat Waynesboro, Va 10+ 127 300327 785430 

01628500 1BSSF100.10 South Fork Shenandoah River near Dooms, Va 10+ 1083 300519 785238 

01638480 1ACAX004.57 Catoctin Cr. at Taylorstown, Va 10+ 89.5 391518 773436 

01654000 1AACO014.57 Accotink Cr. near Annandale, Va 10+ 23.9 384846 771343 

01664000 3-RPP147.10 Rappahannock River at Remington, Va 10+ 252 383150 774850 

01665500 3-RAP066.54 Rapidan River at Ruckersville, Va 10+ 115 381650 782025 

01671100 8-LTL009.54 Little River near Doswell, Va 10+ 107 375221 773048 

01673800 8-POR008.97 Po River near Spotsylvania, Va 10+ 77.6 381017 773542 

01674000 8-MPN094.79 Mattaponi River near Bowling Green, Va 10+ 256 380342 772310 

02011500 2-BCC004.71 Back Cr. near Mountain Grove, Va 10+ 134 380410 795350 

02015700 2-BLP000.79 Bullpasture River at Williamsville, Va 10+ 110 381143 793414 

02020500 2-CFP004.67 Calfpasture River above Mill Cr. at Goshen, Va 10+ 141 375916 792938 

02027500 2-PNY005.29 Piney River At Piney River, Va 10+ 49.4 374208 790140 

02031000 2-MCM005.12 Mechums River near White Hall, Va 10+ 95.3 380609 783535 

02039500 2-APP110.93 Appomattox River at Farmville, Va 10+ 303 371825 772320 

02041000 2-DPC005.20 Deep Cr. near Mannboro, Va 10+ 177 371659 775212 

Table 2. Station information for the 81 stations in the 

Chesapeake Bay Nontidal Monitoring Network. – Continued 
Streamflow – Total Flow to the Chesapeake Bay

 The annual mean streamflow to the Bay for 2011 was 113,000 cubic feet per 

second (ft3s) which was approximately 40 percent greater than the long-term annual 

mean flow from 1937 to 2011 of 78,740 and greater than flow in 2010 as shown in 

figure 3 (methods from Bue, 1968). Total flow entering the Bay in 2011 was the fifth 

highest since the beginning of the record in 1937, resulting in increased annual-mean 

streamflows at 17 of the 31 long-term stations monitored since 1985, predominately 

located in the Susquehanna and Potomac River Basins. 

Figure 3

 Above normal

 Normal

 Below normal

Long-term 

mean flow
Streamflow – Individual Site Data

Graphics produced for each of the 31 long-term monitoring stations 

show annual and seasonal streamflow relative to selected flow statistics. 

Differences between streamflows in 2011 and 2010 were spatially variable. 

Annual mean streamflow in 2011 was more than 100 percent greater than 

flow in 2010 at 5 of the 17 stations located mostly in Pennsylvania and 

northern Maryland (Susquehanna Basin). In contrast, annual mean 

streamflow was less in 2011 than in 2010 at 9 of 13 Virginia stations; at 6 

other stations in the Potomac basin, streamflow was higher by 50 percent or 

more in 2011 compared to flow 2010 (fig. 4). The 90-percent increase in 

streamflow for the Susquehanna River and 1-percent increase for the 

Potomac River more than offset the decrease in streamflow from the other 

seven RIM stations in 2011. 

For the period 1985 through 2011, significant upward trends in 

streamflow were indicated at 2 stations (Susquehanna River at WilkesBarre, Pa. and Susquehanna River at Danville, Pa.), and no significant 

trends in streamflow were indicated at the remaining 29 stations. 
Streamflow – Individual Site Data

Annual streamflow plots 

were produced for all 31 

long-term stations.

(Susquehanna River at 

Conowingo, Md. presented 

as an example)

Seasonal plots produced, 

but not shown.

Streamflow Generalities in 

2011

• Susquehanna Basin much 

greater than normal 

(shown as black bars)

• Potomac Basin slightly 

greater than normal

• James Basin was less than

 normal Figure 4
 

Annual Combined Total Nitrogen Load for the Chesapeake 

Bay River Input Monitoring (RIM) stations

In 2011, the annual combined estimated total nitrogen 

(TN) load for the nine RIM stations was 314 million pounds 

(Mlbs), 103 Mlbs more than the long-term average of 211 

Mlbs (dashed line in fig. 5) for 1990 to 2011, the common 

time period used for the RIM program. The combined TN load 

for the RIM program stations increased by nearly 128 Mlbs to 

314 Mlbs (69 percent) from 2010 to 2011, producing the 

second-highest delivered TN load since 1990. The 

Susquehanna River contributed about 77 percent of the 

combined TN load in 2011. The high correspondence (positive 

correlation) between annual streamflow and the TN combined 

load is apparent in figure 5.
 

Annual Combined Total Nitrogen Load and Mean Streamflow for the 

Chesapeake Bay River Input Monitoring (RIM) stations, 1990-2011 

Figure 5

Mean load
Annual Combined Total Phosphorus Load for the 

Chesapeake Bay River Input Monitoring (RIM) stations

 

 In 2011, the annual combined total phosphorus (TP) 

load (35.1 million pounds, Mlbs) exceeded (and was 160 

percent greater than) the long-term average of 13.3 Mlbs 

(dashed line in fig. 6). The increases in streamflow and 

concentrations from 2010 to 2011 resulted in an estimated TP 

load increase of 22 Mlbs to 35.1 Mlbs and produced the 

highest delivered load since the record began in 1990. Similar 

to TN, the Susquehanna River delivered about 75 percent of 

the combined TP load in 2011. Annual variability in the 

combined TP load is moderately correlated related with the 

variability in streamflow.
 

Annual Combined Total Phosphorus Load and Mean Streamflow for the 

Chesapeake Bay River Input Monitoring (RIM) stations, 1990-2011 

Figure 6

Mean load
Annual Combined Sediment Load for the Chesapeake Bay 

River Input Monitoring (RIM) stations

 

In 2011, the annual combined sediment load at the 

RIM stations, 51,700 million pounds (Mlbs), was the highest 

since the record began in 1990 and nearly 5 times the longterm average of 10,600 Mlbs (fig. 7). The increase in sediment 

loads from 2010 to 2011was caused in large part by two major 

storms in the Susquehanna River Basin which together 

contributed about 75 percent of the combined sediment load. 

Since 1990, the Susquehanna contributes on average about 39 

percent of the sediment entering the Bay from the tributaries. 

The annual combined estimated sediment load increased from 

38,000 Mlbs to 51,700 Mlbs, a 36-percent increase, from 2010 

to 2011.
 

Annual Combined Sediment Load and Mean Streamflow for the 

Chesapeake Bay River Input Monitoring (RIM) stations, 1990-2011 

Figure 7

Mean load
Flow-adjusted Concentrations (FAC)

USGS program ESTIMATOR (Cohn and others, 1989), 

estimates trends over given time period for total nitrogen (TN), 

total phosphorus (TP), and sediment (SED) for 2 time periods, 

1985 to 2011 and 2002 to 2011 

• Uses the slope coefficient (b), time (t), and time (t2) for nonlinearity flow adjusted trend,

• A total of 95 individual model runs were completed for 

each time period for TN, TP, and SED.

These trends are useful:

• For examining effects of management actions,

• Helps to adjust for the “effects” of hydrology and season.
Trends in Flow-adjusted Concentrations (1985-2011) 

Total Nitrogen (TN) – For the RIM monitoring stations, the three 

largest monitored rivers (Susquehanna, Potomac, and James) and the 

Patuxent River had statistically significant downward (improving) trends 

in TN flow-adjusted concentration (FAC) (supplemental data and fig. 8). 

Only the Pamunkey and Choptank RIM stations had statistically 

significant upward (degrading) TN trends. No significant trends were 

indicated at the remaining RIM stations (Rappahannock, Mattaponi, and 

Appomattox). 

In the 31-site long-term network, 21 stations had improving 

trends, 3 stations had degrading trends, and 7 stations had no trend. All 

eight stations in the Susquehanna River Basin, including the RIM site, had 

improving trends in TN FAC over the study period. Of the 11 stations in 

the Potomac River Basin, 9 had improving trends in TN FAC and 2 had no 

statistically significant trend. Three stations in the lower Virginia basins 

had significantly improving trends in TN FAC, one site had an degrading 

trend, and three stations had no statistically significant trend (fig. 8).
Total Nitrogen

Trends in 

Flow-adjusted 

Concentration 

(1985-2011)

Figure 8
Trends in Flow-adjusted Concentrations (1985-2011) 

Total Phosphorus (TP) – With respect to TP flow-adjusted 

concentrations (FAC), the Patuxent, Potomac, and James River Input 

Monitoring (RIM) stations had statistically significant improving trends, 

whereas the Choptank, Pamunkey, and Appomattox River RIM stations 

had statistically significant degrading trends. The RIM site on the 

Susquehanna River indicates a non-significant trend in TP FAC (fig. 9). 

In the nontidal monitoring network, TP trends in FAC were 

improving significantly at 22 of the 31 stations and degrading 

significantly at 4 stations. Five stations did not have statistically 

significant trends. Improving trends were observed at seven of the eight 

stations in the Susquehanna River Basin. In the Potomac River Basin, 

nine stations showed improving trends and one site showed no 

statistically significant trend. In the James River Basin, two stations had 

improving trends and one site had no significant trend. In the entire 

Chesapeake Bay Watershed, 10 of 31 stations had improving trends with 

a magnitude greater than 50 percent, whereas 2 stations had degrading 

trends greater than 50 percent (fig. 9).
Total Phosphorus

Trends in 

Flow-adjusted 

Concentration 

(1985-2011)

Figure 9
Trends in Flow-adjusted Concentrations (1985-2011) 

Sediment – Statistically significant improving trends in sediment 

flow-adjusted concentrations (FAC) were observed for the Potomac, Patuxent, 

and Choptank River Input Monitoring (RIM) stations (fig. 10). The Pamunkey

and Appomattox RIM stations had statistically significant degrading trends in 

sediment FAC. The Susquehanna, James, Rappahannock, and Mattaponi RIM 

stations had no trends.

Statistically significant improving trends in sediment FAC were 

indicated at 9 of the 31 stations and degrading trends at 8 stations. Changes in 

trend magnitude greater than 50 percent were indicated at three of the nine 

improving-trend stations and six of the eight degrading-trend stations (fig. 10). 

In the Susquehanna River Basin, improving trends were indicated for five 

stations. Results for the Potomac River Basin indicate an equal number of 

stations (two) with significant improving and degrading trends; no significantly 

detectable trends were apparent for seven stations. In the lower Virginia River 

basins, five stations had significantly degrading trends, and three stations had 

no detectable significant trend. 
Sediment

Trends in 

Flow-adjusted 

Concentration

(1985-2011)

Figure 10
Comparison of Flow-adjusted Concentrations for Long-term 

and 10-year Trends in Concentration for 31 Stations

 

• There were 24 fewer statistically significant trends in concentration 

in the 10-year period compared to the long-term period.

• 25 of the 50 improving trends for 1985 to 2011 became either 

degrading or not significant for 2002 to 2011. 

(Available on the web at 

1985-2011

(long-term)

2002-2011

(10-year) Difference 

Total

nitrogen

19 Improving 

3 Degrading

9 No trend

12 Improving 

1 Degrading

18 No trend

7 fewer improving stations, 

2 fewer degrading stations,

9 more non-significant stations

Total

phosphorus

22 Improving 

4 Degrading

5 No trend

11 Improving 

4 Degrading

16 No trend

11 fewer improving stations, 

11 more non-significant stations

Sediment

9 Improving 

8 Degrading

14 No trend

2 Improving 

11 Degrading 

18 No trend

7 fewer improving stations, 

3 more degrading stations,

4 more non-significant stations

http://cbrim.er.usgs.gov/.) 
Comparison of 10-year Concentration Trends and 

5-year Average Yields

Trends in flow-adjusted concentrations (FAC) for total nitrogen (TN), 

total phosphorus (TP), and sediment were estimated for two time periods, 

1985-2011 (long-term) and 2002-2011 (10-year), as discussed previously, and 

shown with yields (figs. 11-13). Average annual yields for TN, TP, and 

sediment were estimated from the most recent 5 years (2006-2011) and 

reported in tons per square mile. Data for all trends in FAC and yields can be 

found at the end of the report in the section “Supplemental Data.”

 For the purposes of assessing relative magnitude of water-quality 

problems, yields were categorized as “High,” Medium,” or “Low” by 

dividing the range of yield data into thirds. 
Range Categories of Average Annual Yields for 65 

Monitoring Stations in Chesapeake Bay Basin 

(2006-2011)

Range 

Category 

Total Nitrogen

(tons/mi2) 

Total 

Phosphorus 

(tons/mi2) 

Sediment 

(tons/mi2) 

High >2.5 to 10.5 >0.20 to 0.62 >196 to 458

Medium >1.5 to 2.5 >0.11 to 0.20 >82 to 196

Low 0.3 to 1.5 0.04 to 0.11 38 to 82
Spatial Distribution of 5-year Average TN, TP, and Sediment Yields

Generally, higher yields for TN (fig. 11) were prevalent in the middle of 

the Bay watershed, areas that coincide with large areas of urban and agricultural 

land uses. The lowest yields were generally in the Virginia watersheds. 

 Generally, higher yields for TP (fig. 12) were prevalent in the middle of 

the Bay watershed, areas that coincide with large urban and agricultural land uses. 

The lowest yields were generally in the western areas of the Bay watershed, an 

area dominated by forests. 

Generally, spatial patterns are less discernible for sediment yields (fig. 13) 

than for TN and TP except for higher yields in the middle of the watershed, areas 

where TN and TP were also highest. The lowest yields were generally in the 

western areas of the Bay watershed, an area dominated by forests, and the flat 

topography of the Eastern Shore of Maryland and Delaware. 

 
Figure 11. Total nitrogen 10-year concentration trends (A) and 5-year yields (B).

A B 

Yields in tons 

per square 

mile
Figure 12. Total phosphorus 10-year concentration trends (A) and 5-year yields (B).

A B 

Yields in tons 

per square 

mile
Figure 13. Sediment concentration 10-year trends (A) and 5-year yields (B).

A B 

Yields in tons 

per square 

mile
Combined Water-Quality Indicator

The USGS, working with Chesapeake Bay Program partners, 

developed a new water-quality indicator in 2010 to interpret monitoring 

data for total nitrogen, total phosphorus, and sediment. The indicator 

combines the results of the 10-year trend analysis for flow-adjusted 

concentrations (32 stations) with results of average yields estimated from 5 

years of data for a greater number of stations (65 primary stations). The 

same is true for total phosphorus and sediment. Four classifications for 10-

year trends (arrows, dashes) were combined with 5-year annual yields 

(grouped into thirds and color coded) to produce a classification system 

consisting of 12 categories. 

The combined indicator figures (figs. 14 and 15) show decreasing 

concentrations of total nitrogen and phosphorus in areas of the watershed 

that have relatively high nutrient yields. The combined indicator figure for 

sediment (fig. 16) shows less decreasing concentrations in areas with 

relatively high yields. These results support the idea that progress has been 

made in response to efforts to reduce inputs of nutrients, but perhaps less so 

for sediment, from the watershed to the Bay. 
Total Nitrogen (TN) 

Combined Indicator

 Twelve of the 32 stations had 

improving trends in TN flowadjusted concentrations. 

Spatially, higher yields are 

distributed in the middle of Bay 

watershed whereas lower yields 

predominate in southern areas 

Bay watershed. 

 The results indicate that 

progress has been made in 

response to recent efforts to 

reduce inputs of nitrogen to the 

Bay from the watershed. 

Figure 14
Total Phosphorus (TP) 

Combined Indicator 

 Twelve of the 32 stations had 

improving trends in TP 

concentrations, with 9 of the 12 

stations in areas of relatively 

high total phosphorus yields. 

Spatially, no distribution is 

apparent, except for lower yields 

in the western Potomac River 

Basin (black arrow). 

 The combined figure indicates 

that progress has been made in 

response to recent efforts to 

reduce inputs of phosphorus to 

the Bay from the watershed. 

Figure 15
Sediment Combined

Indicator 

 Three of the 31 stations had 

improving trends in sediment 

concentrations. In contrast, nine 

stations indicate degrading trends 

and all these stations were in the 

southern half of the watershed in 

areas of variable (low, medium, 

and high) sediment yields. 

Spatially, no distribution is 

apparent, except perhaps lower 

yields for the Eastern Shore of 

Maryland and Delaware (black 

arrow) and predominately forested 

areas. 

 The combined figure indicates 

that less progress (compared to 

that for nitrogen and phosphorus) 

has been made in response to 

recent efforts to reduce inputs of 

sediment to the Bay from the 

watershed. Figure 16
Water-Quality Indicator Summary

The water-quality indicator table summary (table 3) provides managers 

and scientists with combinations of trends and yields. A degrading water-quality 

trend and a high yield at a station might be considered a “poor” (red) combination. 

In contrast, an improving water-quality trend and a low yield might be considered 

a “good” (blue) combination – the goal for all stations. Of the 31 stations, 5 would 

be classified as “poor” (16 percent) and 7 stations would be classified as “good” 

(22 percent) for TN, TP, and sediment. If managers and scientists wanted to 

consider stations near the middle of the range (improving or not-significant trends 

and medium yields) for economic or environmental feasibility reasons, then 34 

out of 96 trend/yield combinations could be classified as “fair” (35 percent) for 

TN, TP, and sediment. 

 For nutrients and sediment, more “good” areas generally are located in 

parts of the upper and western Susquehanna and western Potomac River Basins, 

and many locations in Virginia. In contrast, “poor” areas tend to be located in the 

middle of the Chesapeake Bay Watershed. Locations classified as “good” tend to 

be dominated by forested land, whereas those classified as “poor” tend to be 

dominated by urban and agricultural land uses.
Table 3. Water-quality indicator summary.

10-year flow-adjusted concentration trend for 32 stations 

(2002-2011)

Total Nitrogen

5-year Yields 

(2006-2011)

Yield Degrading 

(upward) Not significant Improving (downward)

Trends not 

available

high 1 4 3 14

medium 0 7 6 10

low 0 8 3 9

Total Phosphorus

5-year Yields 

(2006-2011)

Yield Degrading 

(upward) Not significant Improving (downward)

Trends not 

available

high 2 6 1 12

medium 1 5 8 8

low 1 6 2 13

Sediment

5-year Yields

 (2006-2011)

Yield Degrading 

(upward) Not significant Improving 

(downward)

Trends not 

available

high 2 8 1 11

medium 3 8 0 9

low 5 3 2 13

33 stations currently are classified as “trends not available,” of which 13 and 20 

stations are expected to have trends in 2013 and 2014, respectively.
Summary 

• The number of Primary stations increased from 64 in 2010 to 65 in 2011, one 

site was dropped and 2 stations were added. 

• Annual mean streamflow to the Chesapeake Bay in 2011 was 40 percent 

greater than the long-term mean (1937-2011) and also as compared to 

2010.

• Two of the 31 long-term monitoring stations (both in the Susquehanna River 

Basin) had statistically significant increasing trends indicating

increase in streamflow (1985-2011).

• Trends in flow-adjusted concentration at the long-term stations showed 

improving conditions for total nitrogen (21 stations) and total 

phosphorus (22 stations) and an equal number of improving and 

degrading conditions (9 stations) for sediment from 1985-2011.

• For total nitrogen, yields estimated from 2006-2011 data were relatively 

higher in the middle of the Bay watershed and lower in the southern 

part of the Bay watershed. 
Summary – Continued 

• For total phosphorus, the spatial distribution of yields was similar to total 

 nitrogen; highest in the central and eastern areas of the watershed and

 generally lowest in the western Potomac River Basin 

• For sediment, no discernible spatial pattern in yield was indicated, except

 lower yields in the coastal plain of Maryland and Delaware and 

predominately forested areas of the watershed. 

• There were fewer stations with significantly degrading trends and more 

stations with no significant change in the 10-year time period 

compared to the long-term time period (1985-2011)

• Using a combined nontidal water-quality indicator (based on both trends and

 yields) approach, there are more “good” than “poor” station

 classifications for total nitrogen whereas total phosphorus and 

sediment are equal 

• Evaluation of monitoring data using the combined indicator approach 

suggests that progress has been made in response to efforts to 

reduce inputs of nutrients, but perhaps not sediment, from the 

watershed to the Bay. 
References Cited

Bue, C.D., 1968, Monthly surface-water input to Chesapeake Bay: 

U.S. Geological Survey Open-File Report 68–29, 45 p. 

Cohn, T.A., Delong, L.L., Gilroy, E.J., Hirsch, R.M., and Wells, D., 1989, 

Estimating constituent loads: Water Resources Research, v. 25, no. 

5, p. 937–942. 

Langland, M.J., Phillips, S.W., Raffensperger, J.P., Moyer, D.L., Landwehr, 

J.M., and Schwarz, G.E., 2006, Changes in streamflow and water 

quality in selected nontidal stations in the Chesapeake Bay Basin, 

1985–2004: U.S. Geological Survey Scientific Investigations Report 

2006–5178, 75 p. 

Langland, Michael, Blomquist, Joel, Moyer, Douglas, and Hyer, Kenneth, 

2012, Nutrient and suspended-sediment trends, loads, and yields and 

development of an indicator of streamwater quality at nontidal sites 

in the Chesapeake Bay watershed, 1985–2010: U.S. Geological 

Survey Scientific Investigations Report 2012–5093, 26 p.
References Cited – Continued 

U.S. Environmental Protection Agency, 2004, Establishing a Chesapeake 

Bay nontidal watershed water-quality network: Prepared by the 

Chesapeake Bay Program's Nontidal Water-Quality Monitoring 

Workgroup, September 2004, 28 p.
Appendix 1. Supplemental Data – Long-term Trends

Flow-adjusted trends in total nitrogen concentrations, 1985-2011 for 31 long-term stations.

STATION Station Name Constituent Trend in 

percent Significance

01491000 Choptank River Near Greensboro, Md. Total Nitrogen 7.3 DEGRADING

01531500 Susquehanna River At Towanda, Pa Total Nitrogen -45.7 IMPROVING

01536500 Susquehanna River At Wilkes-Barre, Pa Total Nitrogen -41.4 IMPROVING

01540500 Susquehanna River At Danville, Pa Total Nitrogen -44.8 IMPROVING

01553500 West Branch Susquehanna River At Lewisburg, Pa Total Nitrogen -31.7 IMPROVING

01567000 Juniata River At Newport, Pa Total Nitrogen -15.1 IMPROVING

01576000 Susquehanna River At Marietta, Pa Total Nitrogen -26.7 IMPROVING

01576754 Conestoga River At Conestoga, Pa Total Nitrogen -22.5 IMPROVING

01578310 Susquehanna River At Conowingo, Md Total Nitrogen -20.5 IMPROVING

01582500 Gunpowder Falls At Glencoe, Md Total Nitrogen 5.6 DEGRADING

01586000 North Branch Patapsco River At Cedarhurst, Md Total Nitrogen 1.9 not significant

01591000 Patuxent River Near Unity, Md Total Nitrogen 6.7 not significant

01594440 Patuxent River At Bowie, Md Total Nitrogen -56.5 IMPROVING

01599000 Georges Creek At Franklin, Md Total Nitrogen -44.9 IMPROVING

01601500 Wills Creek Near Cumberland, Md Total Nitrogen -46.1 IMPROVING

01614500 Conococheague Creek At Fairview, Md Total Nitrogen -10.9 IMPROVING

01619500 Antietam Creek Near Sharpsburg, Md Total Nitrogen -23.7 IMPROVING

01631000 S F Shenandoah River At Front Royal, Va Total Nitrogen -37.4 IMPROVING

01634000 N F Shenandoah River Near Strasburg, Va Total Nitrogen -2.1 not significant

01637500 Catoctin Creek Near Middletown, Md Total Nitrogen -28.1 IMPROVING

01639000 Monocacy River At Bridgeport, Md Total Nitrogen -29.3 IMPROVING

01646580 Potomac River At Chain Bridge, Md Total Nitrogen -24.6 IMPROVING

01651000 Nw Branch Anacostia River Near Hyattsville, Md Total Nitrogen -20.7 IMPROVING

01668000 Rappahannock River Near Fredericksburg, Va Total Nitrogen -8.9 not significant

01671020 North Anna River At Hart Corner Near Doswell, Va Total Nitrogen 3.6 not significant

01673000 Pamunkey River Near Hanover, Va Total Nitrogen 21.1 DEGRADING

01674500 Mattaponi River Near Beulahville, Va Total Nitrogen 1.9 not significant

02035000 James River At Cartersville, Va Total Nitrogen -15.5 IMPROVING

02037500 James River Near Richmond, Va Total Nitrogen -16.2 IMPROVING

02041650 Appomattox River At Matoaca, Va Total Nitrogen 6.3 not significant

02042500 Chichamominy River Near Providence Forge, Va Total Nitrogen -20.2 IMPROVING
Appendix 1. Supplemental Data – Long-term Trends

Flow-adjusted trends in total phosphorus concentrations, 1985-2011 for 31 long-term stations.

STATION Station Name Constituent Trend in 

percent Significance

01531500 Susquehanna River At Towanda, Pa Total Phosphorus -22.7 IMPROVING

01536500 Susquehanna River At Wilkes-Barre, Pa Total Phosphorus -57.1 IMPROVING

01540500 Susquehanna River At Danville, Pa Total Phosphorus -32.8 IMPROVING

01553500 West Branch Susquehanna River At Lewisburg, Pa Total Phosphorus -50.8 IMPROVING

01567000 Juniata River At Newport, Pa Total Phosphorus -48.5 IMPROVING

01576000 Susquehanna River At Marietta, Pa Total Phosphorus -32.3 IMPROVING

01576754 Conestoga River At Conestoga, Pa Total Phosphorus -62.2 IMPROVING

01578310 Susquehanna River At Conowingo, Md Total Phosphorus 2 not significant

01582500 Gunpowder Falls At Glencoe, Md Total Phosphorus -43.9 IMPROVING

01586000 North Branch Patapsco River At Cedarhurst, Md Total Phosphorus -47.8 IMPROVING

01591000 Patuxent River Near Unity, Md Total Phosphorus -71.6 IMPROVING

01594440 Patuxent River At Bowie, Md Total Phosphorus -55.7 IMPROVING

01599000 Georges Creek At Franklin, Md Total Phosphorus -52.7 IMPROVING

01601500 Wills Creek Near Cumberland, Md Total Phosphorus -36.3 IMPROVING

01614500 Conococheague Creek At Fairview, Md Total Phosphorus -71.1 IMPROVING

01619500 Antietam Creek Near Sharpsburg, Md Total Phosphorus -65.2 IMPROVING

01631000 S F Shenandoah River At Front Royal, Va Total Phosphorus -48 IMPROVING

01634000 N F Shenandoah River Near Strasburg, Va Total Phosphorus -62.7 IMPROVING

01637500 Catoctin Creek Near Middletown, Md Total Phosphorus -45.3 IMPROVING

01639000 Monocacy River At Bridgeport, Md Total Phosphorus -27.3 IMPROVING

01646580 Potomac River At Chain Bridge, Md Total Phosphorus -15.2 IMPROVING

01651000 Nw Branch Anacostia River Near Hyattsville, Md Total Phosphorus -16.9 not significant

01668000 Rappahannock River Near Fredericksburg, Va Total Phosphorus -6.1 not significant

01671020 North Anna River At Hart Corner Near Doswell, Va Total Phosphorus 42.8 DEGRADING

01673000 Pamunkey River Near Hanover, Va Total Phosphorus 102.8 DEGRADING

01674500 Mattaponi River Near Beulahville, Va Total Phosphorus -6.1 not significant

02035000 James River At Cartersville, Va Total Phosphorus -61.2 IMPROVING

02037500 James River Near Richmond, Va Total Phosphorus -40.4 IMPROVING

02041650 Appomattox River At Matoaca, Va Total Phosphorus 27 DEGRADING

02042500 Chichamominy River Near Providence Forge, Va Total Phosphorus -11.2 not significant
Appendix 1. Supplemental Data – Long-term Trends

Flow-adjusted trends in sediment concentration, 1985-2011 for 31 long-term stations.

STATION Station Name Constituent Trend in 

percent Significance

01491000 Choptank River Near Greensboro, Md. Total Suspended Sediment -30.9 IMPROVING

01531500 Susquehanna River At Towanda, Pa Total Suspended Sediment -12.1 not significant

01536500 Susquehanna River At Wilkes-Barre, Pa Total Suspended Solids -60.3 IMPROVING

01540500 Susquehanna River At Danville, Pa Total Suspended Sediment -33.7 IMPROVING

01553500 West Branch Susquehanna River At Lewisburg, Pa Total Suspended Sediment -7.2 not significant

01567000 Juniata River At Newport, Pa Total Suspended Sediment -28.4 IMPROVING

01576000 Susquehanna River At Marietta, Pa Total Suspended Sediment -37.4 IMPROVING

01576754 Conestoga River At Conestoga, Pa Total Suspended Sediment -73.8 IMPROVING

01578310 Susquehanna River At Conowingo, Md Total Suspended Sediment -9.3 not significant

01582500 Gunpowder Falls At Glencoe, Md Total Suspended Solids 60.1 DEGRADING

01586000 North Branch Patapsco River At Cedarhurst, Md Total Suspended Solids -24.5 not significant

01591000 Patuxent River Near Unity, Md Total Suspended Solids 14 not significant

01594440 Patuxent River At Bowie, Md Total Suspended Sediment -41.8 IMPROVING

01599000 Georges Creek At Franklin, Md Total Suspended Solids 26.4 not significant

01601500 Wills Creek Near Cumberland, Md Total Suspended Solids 16.6 not significant

01614500 Conococheague Creek At Fairview, Md Total Suspended Solids 20.2 not significant

01619500 Antietam Creek Near Sharpsburg, Md Total Suspended Solids -18.7 not significant

01631000 S F Shenandoah River At Front Royal, Va Total Suspended Solids 18.4 not significant

01634000 N F Shenandoah River Near Strasburg, Va Total Suspended Solids 57.8 DEGRADING

01637500 Catoctin Creek Near Middletown, Md Total Suspended Solids 48.5 DEGRADING

01639000 Monocacy River At Bridgeport, Md Total Suspended Solids -43.6 IMPROVING

01646580 Potomac River At Chain Bridge, Md Total Suspended Sediment -57.5 IMPROVING

01651000 Nw Branch Anacostia River Near Hyattsville, Md Total Suspended Solids 6.9 not significant

01668000 Rappahannock River Near Fredericksburg, Va Total Suspended Solids -2 not significant

01671020 North Anna River At Hart Corner Near Doswell, Va Total Suspended Solids 273.8 DEGRADING

01673000 Pamunkey River Near Hanover, Va Total Suspended Solids 143.7 DEGRADING

01674500 Mattaponi River Near Beulahville, Va Total Suspended Solids 4.5 not significant

02035000 James River At Cartersville, Va Total Suspended Solids 3.4 not significant

02037500 James River Near Richmond, Va Total Suspended Solids 51.6 DEGRADING

02041650 Appomattox River At Matoaca, Va Total Suspended Solids 28.6 DEGRADING

02042500 Chichamominy River Near Providence Forge, Va Total Suspended Solids 72.5 DEGRADING
Appendix 2. Supplemental Data – 10-year Trends

Flow-adjusted trends in total nitrogen concentrations, 2002-2011 for 32 stations.

STATION Station Name Constituent FA trend in 

percent Significance

01531500 Susquehanna River At Towanda, Pa Total Nitrogen -17.9 IMPROVING

01536500 Susquehanna River At Wilkes-Barre, Pa Total Nitrogen -27.3 IMPROVING

01540500 Susquehanna River At Danville, Pa Total Nitrogen -8.7 IMPROVING

01553500 West Branch Susquehanna River At Lewisburg, Pa Total Nitrogen -18.2 IMPROVING

01567000 Juniata River At Newport, Pa Total Nitrogen -13.3 IMPROVING

01576000 Susquehanna River At Marietta, Pa Total Nitrogen -22.9 IMPROVING

01576754 Conestoga River At Conestoga, Pa Total Nitrogen -16.1 IMPROVING

01578310 Susquehanna River At Conowingo, Md Total Nitrogen 5.3 not significant

01491000 Choptank River Near Greensboro, Md. Total Nitrogen 6 not significant

01582500 Gunpowder Falls At Glencoe, Md Total Nitrogen 12.1 DEGRADING

01586000 North Branch Patapsco River At Cedarhurst, Md Total Nitrogen 2.1 not significant

01591000 Patuxent River Near Unity, Md Total Nitrogen 5.5 not significant

01594440 Patuxent River At Bowie, Md Total Nitrogen -18.1 IMPROVING

01599000 Georges Creek At Franklin, Md Total Nitrogen -11.2 not significant

01601500 Wills Creek Near Cumberland, Md Total Nitrogen -38.6 IMPROVING

01614500 Conococheague Creek At Fairview, Md Total Nitrogen -1.9 not significant

01619500 Antietam Creek Near Sharpsburg, Md Total Nitrogen 1 not significant

01631000 S F Shenandoah River At Front Royal, Va Total Nitrogen 5.9 not significant

01634000 N F Shenandoah River Near Strasburg, Va Total Nitrogen -15.5 IMPROVING

01637500 Catoctin Creek Near Middletown, Md Total Nitrogen -5.1 not significant

01639000 Monocacy River At Bridgeport, Md Total Nitrogen -33.8 IMPROVING

01646580 Potomac River At Chain Bridge, Md Total Nitrogen -1.5 not significant

01651000 Nw Branch Anacostia River Near Hyattsville, Md Total Nitrogen 17.8 not significant

01668000 Rappahannock River Near Fredericksburg, Va Total Nitrogen -5.6 not significant

01671020 North Anna River At Hart Corner Near Doswell, Va Total Nitrogen -21.7 IMPROVING

01673000 Pamunkey River Near Hanover, Va Total Nitrogen 1.3 not significant

01674500 Mattaponi River Near Beulahville, Va Total Nitrogen -4.1 not significant

02035000 James River At Cartersville, Va Total Nitrogen 3.3 not significant

02037500 James River Near Richmond, Va Total Nitrogen -0.8 not significant

02041650 Appomattox River At Matoaca, Va Total Nitrogen 4.7 not significant

02042500 Chickahominy River Near Providence Forge, Va Total Nitrogen -29.8 not significant

01589300 Gwynn Falls At Villa Nova, Md Total Nitrogen -4.2 not significant
Appendix 2. Supplemental Data – 10-year Trends

Flow-adjusted trends in total phosphorus concentrations, 2002-2011 for 32 stations.

STATION Station Name Constituent FA trend in 

percent Significance

01531500 Susquehanna River At Towanda, Pa Total Phosphorus 11 not significant

01536500 Susquehanna River At Wilkes-Barre, Pa Total Phosphorus -24.1 not significant

01540500 Susquehanna River At Danville, Pa Total Phosphorus 12.3 not significant

01553500 West Branch Susquehanna River At Lewisburg, Pa Total Phosphorus -2.9 not significant

01567000 Juniata River At Newport, Pa Total Phosphorus -51.8 IMPROVING

01576000 Susquehanna River At Marietta, Pa Total Phosphorus -39.2 IMPROVING

01576754 Conestoga River At Conestoga, Pa Total Phosphorus -47.8 IMPROVING

01578310 Susquehanna River At Conowingo, Md Total Phosphorus 15.2 not significant

01491000 Choptank River Near Greensboro, Md. Total Phosphorus -0.9 not significant

01582500 Gunpowder Falls At Glencoe, Md Total Phosphorus 12.1 not significant

01586000 North Branch Patapsco River At Cedarhurst, Md Total Phosphorus 9.7 not significant

01591000 Patuxent River Near Unity, Md Total Phosphorus 13.3 not significant

01594440 Patuxent River At Bowie, Md Total Phosphorus -9.8 not significant

01599000 Georges Creek At Franklin, Md Total Phosphorus 8.3 not significant

01601500 Wills Creek Near Cumberland, Md Total Phosphorus 65.4 DEGRADING

01614500 Conococheague Creek At Fairview, Md Total Phosphorus -49.3 IMPROVING

01619500 Antietam Creek Near Sharpsburg, Md Total Phosphorus 3 not significant

01631000 S F Shenandoah River At Front Royal, Va Total Phosphorus -61 IMPROVING

01634000 N F Shenandoah River Near Strasburg, Va Total Phosphorus -86.4 IMPROVING

01637500 Catoctin Creek Near Middletown, Md Total Phosphorus -49.8 IMPROVING

01639000 Monocacy River At Bridgeport, Md Total Phosphorus -20.9 IMPROVING

01646580 Potomac River At Chain Bridge, Md Total Phosphorus -15.1 not significant

01651000 Nw Branch Anacostia River Near Hyattsville, Md Total Phosphorus 55.4 DEGRADING

01668000 Rappahannock River Near Fredericksburg, Va Total Phosphorus 42.6 DEGRADING

01671020 North Anna River At Hart Corner Near Doswell, Va Total Phosphorus 84.9 DEGRADING

01673000 Pamunkey River Near Hanover, Va Total Phosphorus -22.3 IMPROVING

01674500 Mattaponi River Near Beulahville, Va Total Phosphorus 9.6 not significant

02035000 James River At Cartersville, Va Total Phosphorus -43.7 IMPROVING

02037500 James River Near Richmond, Va Total Phosphorus -42.8 IMPROVING

02041650 Appomattox River At Matoaca, Va Total Phosphorus 18.9 not significant

02042500 Chickahominy River Near Providence Forge, Va Total Phosphorus -36.2 not significant

01589300 Gwynn Falls At Villa Nova, Md Total Phosphorus 10 not significant
Appendix 2. Supplemental Data – 10-year Trends

Flow-adjusted trends in sediment concentrations, 2002-2011 for 32 stations.

STATION Station Name Constituent FA trend in 

percent Significance

01531500 Susquehanna River At Towanda, Pa Sediment 4.8 not significant

01536500 Susquehanna River At Wilkes-Barre, Pa Sediment 30.7 not significant

01540500 Susquehanna River At Danville, Pa Sediment -2.7 not significant

01553500 West Branch Susquehanna River At Lewisburg, Pa Sediment -2.4 not significant

01567000 Juniata River At Newport, Pa Sediment -43.5 IMPROVING

01576000 Susquehanna River At Marietta, Pa Sediment -5.6 not significant

01576754 Conestoga River At Conestoga, Pa Sediment -39.7 IMPROVING

01578310 Susquehanna River At Conowingo, Md Sediment 44 DEGRADING

01491000 Choptank River Near Greensboro, Md. Sediment 46.2 DEGRADING

01582500 Gunpowder Falls At Glencoe, Md Sediment 115.6 DEGRADING

01586000 North Branch Patapsco River At Cedarhurst, Md Sediment 67.4 not significant

01591000 Patuxent River Near Unity, Md Sediment 138 DEGRADING

01594440 Patuxent River At Bowie, Md Sediment 40.2 not significant

01599000 Georges Creek At Franklin, Md Sediment 157.4 DEGRADING

01601500 Wills Creek Near Cumberland, Md Sediment 73.9 not significant

01614500 Conococheague Creek At Fairview, Md Sediment -19.5 not significant

01619500 Antietam Creek Near Sharpsburg, Md Sediment 20.6 not significant

01631000 S F Shenandoah River At Front Royal, Va Sediment -8.3 not significant

01634000 N F Shenandoah River Near Strasburg, Va Sediment 21.3 not significant

01637500 Catoctin Creek Near Middletown, Md Sediment 39.9 not significant

01639000 Monocacy River At Bridgeport, Md Sediment -5.6 not significant

01646580 Potomac River At Chain Bridge, Md Sediment 56.5 DEGRADING

01651000 Nw Branch Anacostia River Near Hyattsville, Md Sediment 236.2 DEGRADING

01668000 Rappahannock River Near Fredericksburg, Va Sediment 18.2 not significant

01671020 North Anna River At Hart Corner Near Doswell, Va Sediment 46.4 not significant

01673000 Pamunkey River Near Hanover, Va Sediment 73.7 DEGRADING

01674500 Mattaponi River Near Beulahville, Va Sediment -20.3 not significant

02035000 James River At Cartersville, Va Sediment 20.7 not significant

02037500 James River Near Richmond, Va Sediment 57.4 DEGRADING

02041650 Appomattox River At Matoaca, Va Sediment 44.8 DEGRADING

02042500 Chickahominy River Near Providence Forge, Va Sediment 679.3 DEGRADING

01589300 Gwynn Falls At Villa Nova, Md Sediment 65.3 not significant
Appendix 3. Supplemental Data – 5-year Annual-Average Yields

Yields in tons per square mile (tons/mi2) 2006-2011, for 65 stations 

STATION Station Name

Total nitrogen

mean yield 

[tons/mi2]

Total phosphorus 

mean yield 

[tons/mi2]

Sediment mean 

yield [tons/mi2]

01531500 SUSQUEHANNA RIVER AT TOWANDA, PA 4.76 0.508 764.7

01536500 SUSQUEHANNA RIVER AT WILKES-BARRE, PA 1.57 0.261 2061.0

01540500 SUSQUEHANNA RIVER AT DANVILLE, PA 1.77 0.196 196.5

01553500 WEST BRANCH SUSQUEHANNA RIVER AT LEWISBURG, PA 1.41 0.072 62.1

01567000 JUNIATA RIVER AT NEWPORT, PA 2.32 0.085 56.8

01576000 SUSQUEHANNA RIVER AT MARIETTA, PA 2.31 0.159 187.6

01576754 CONESTOGA RIVER AT CONESTOGA, PA 10.48 0.616 457.9

01578310 SUSQUEHANNA RIVER AT CONOWINGO DAM, MD 2.51 0.157 170.2

01491000 CHOPTANK RIVER NEAR GREENSBORO, MD 2.49 0.238 38.8

01582500 GUNPOWDER FALLS AT GLENCOE,MD 3.35 0.066 97.1

01586000 NORTH BRANCH PATAPSCO AT CEDARHURST, MD 4.43 0.144 322.4

01591000 PATUXENT RIVER NEAR UNITY, MD 3.16 0.124 316.5

01594440 PATUXENT RIVER NEAR BOWIE, MD 1.81 0.176 111.0

01599000 GEORGES CREEK AT GLENCOE, MD 1.89 0.096 108.8

01601500 WILLS CREEK NEAR CUMBERLAND, MD 1.97 0.111 196.0

01614500 CONOCOCHEAGUE CREEK AT FAIRVIEW, MD 5.85 0.153 99.7

01619500 ANTIETAM CREEK NEAR SHARPSBURG, MD 4.64 0.144 54.8

01631000 SF SHENANDOAH RIVER AT FRONT ROYAL, VA 1.38 0.156 130.6

01634000 NF SHENANDOAH RIVER NEAR STRASBURG, VA 1.48 0.115 323.2

01637500 CATOCTIN CREEK NEAR MIDDLETOWN, MD 2.20 0.145 210.1

01639000 MONOCACY RIVER AT BRIDGPORT, MD 3.47 0.324 113.2

01646580 POTOMAC RIVER AT CHAIN BRIDGE 1.88 0.143 184.0

01651000 NW BRANCH ANACOSTIA RIVER NEAR HYATTSVILLE, MD. 2.21 0.277 477.5

01668000 RAPPAHANNOCK RIVER NEAR FREDERICKSBURG, VA 1.14 0.242 317.5

01671020 NORTH ANNA RIVER AT HART CORNER NEAR DOSWELL, VA 0.37 0.039 38.2

01673000 PAMUNKEY RIVER NEAR HANOVER, VA 0.55 0.074 50.5

01674500 MATTAPONI RIVER NEAR BEULAHVILLE, VA 0.54 0.048 13.2

02035000 JAMES RIVER AT CARTERSVILLE, VA 0.72 0.128 136.4

02037500 JAMES RIVER AT RICHMOND, VA 0.70 0.153 154.3

02041650 APPOMATTOX RIVER AT MATOACA, VA 0.46 0.045 13.4

02042500 CHICKAHOMINY RIVER NEAR PROVIDEN FORGE, VA 0.70 0.109 32.7

01589300 GWYNNS FALLS AT VILLA NOVA, MD 2.15 0.206 618.1

01515000 SUSQUEHANNA RIVER NEAR WAVERLY, NY 1.94 0.218 259.8

01531000 CHEMUNG RIVER AT CHEMUNG, NY 1.36 0.152 163.8
Appendix 3. Supplemental Data – 5-year Annual-Average Yields

Yields in tons per square mile (tons/mi2) 2006-2011, for 65 stations 

STATION Station Name

Total nitrogen

mean yield 

[tons/mi2]

Total phosphorus 

mean yield 

[tons/mi2]

Sediment mean 

yield [tons/mi2]

01542500 WB SUSQUEHANNA RIVER AT KARTHAUS, PA 1.11 0.050 53.0

01555000 PENNS CREEK AT PENNS CREEK, PA 2.53 0.115 56.5

01562000 RAYSTOWN BRANCH JUNIATA RIVER AT SAXTON, PA 2.45 0.095 102.2

01568000 SHERMAN CREEK AT SHERMANS DALE, PA 6.09 0.505 269.0

01570000 CONODOGUINET CREEK NEAR HOGESTOWN, PA 5.50 0.109 97.3

01571500 YELLOW BREECHES CREEK NR CAMP HILL, PA 3.41 0.123 76.8

01573560 SWATARA CREEK NEAR HERSHEY, PA 6.85 1.065 1381.4

01574000 WEST CONEWAGO CREEK NEAR MANCHESTER, PA 4.05 0.527 425.4

01576787 PEQUEA CREEK NEAR MARTIC FORGE, PA 9.81 0.590 315.4

01667500 RAPIDAN RIVER NEAR CULPEPPER, VA 1.52 0.437 535.1

01487000 NANTICOKE RIVER NEAR BRIDGEVILLE, DE 7.12 0.097 12.0

01488500 MARSHYHOPE CREEK NEAR ADAMSVILLE, DE 4.22 0.287 34.8

01491500 Tuckahoe Creek near Ruthsburg, MD 4.71 0.233 28.2

01495000 Big Elk Creek at Elk Mills, MD 5.87 0.446 840.0

01502500 UNADILLA RIVER AT ROCKDALE, NY 2.09 0.196 269.9

01503000 SUSQUEHANNA RIVER AT CONKLIN, NY 1.73 0.195 214.4

01529500 COHOCTON RIVER NEAR CAMPBELL NY 1.89 0.097 37.6

01549760 WEST BRANCH SUSQUEHANNA RIVER NEAR JERSEY SHORE 1.04 0.059 43.8

01578475 OCTORARO CREEK AT RICHARDSMERE, MD 8.56 0.255 89.8

01580520 Deer Creek near Darlington, MD 4.98 0.219 298.9

01594526 WESTERN BRANCH AT UPPER MARLBORO. MD 1.48 0.409 812.1

01604500 PATTERSON CREEK NEAR HEADSVILLE, WV 0.93 0.057 69.7

01608500 SOUTH BRANCH POTOMAC RIVER NEAR SPRINGFIELD, WV 0.96 0.083 70.8

01610155 SIDELING HILL CREEK NEAR BELLEGROVE, MD 1.27 0.034 78.6

01611500 CACAPON RIVER NEAR GREAT CACAPON, WV 0.93 0.065 99.9

01613095 Tonoloway Creek near Hancock, MD 1.90 0.062 110.9

01613525 LICKING CREEK NEAR PECTONVILLE, MD 1.87 0.076 154.2

01616500 OPEQUON CREEK NEAR MARTINSBURG, WV 2.13 0.181 72.5

01619000 ANTIETAM CREEK NEAR WAYNESBORO, PA 4.73 0.190 76.8

02024752 JAMES RIVER AT BLUE RIDGE PKWY BRIDGE NR BIG ISLAND, VA 0.63 0.092 88.7

01609000 Town Creek near Oldtown, MD 0.91 0.043 125.3


Langland and others—Total Nutrient and Sediment Loads, Trends, Yields, and Nontidal Water-Quality Indicators, Chesapeake Bay Watershed, 1985–2011—Open-File Report 2013–1052