Summary of Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Nontidal Network Stations: Water Year 2016 Update

Prepared by Douglas L. Moyer and Joel D. Blomquist, U.S. Geological Survey, December 13, 2017

Changes in nitrogen, phosphorus, and suspended-sediment loads in rivers across the Chesapeake Bay watershed have been calculated using monitoring data from 115 stations that are part of the Non-tidal monitoring network (NTN) (Moyer and others, 2017). Constituent loads are calculated with at least five years of monitoring data and trends are reported after at least ten years of data collection. Data collection began in 1985 at nine of these locations, referred to as River Input Monitoring (RIM) stations, where loads are delivered directly to tidal waters. These results are used to help assess efforts to decrease nutrient and sediment loads being delivered to the bay. Additional information for each monitoring station is available through the USGS Chesapeake Bay Nontidal Web site (https://cbrim.er.usgs.gov/) that provides State, Federal, and local partners, as well as the general public, ready access to a wide range of data for nutrient and sediment conditions across the Chesapeake Bay watershed. Results from two time periods are reported in this summary: a long-term time period (1985- 2016), and short-term time period (2007-2016). All annual results are based on a water year which extends from October 1 to September 30. The results are summarized for 1. loads delivered directly to the tidal waters for the most recent year (Water Year 2016); specifically, the combined load from the nine River Input Monitoring (RIM) stations, 2. trends in loads at the RIM stations over the long- and short-time periods, and 3. patterns in loads and trends at the 115 NTN monitoring stations in the bay watershed (that are part of the Chesapeake Bay Program (CBP) NTN) over the short-term period.

What are the patterns in loads delivered to tidal waters from the RIM stations?

The USGS combined the load results from the nine RIM stations shown in figure 1 to quantify the total nitrogen, phosphorus, and suspended-sediment loads delivered from the watershed to tidal waters. Together, the nine RIM stations reflect loads delivered from 78 percent of its 64,000-square-mile watershed.

River flow and loads to tidal waters  Estimated annual-mean streamflow entering the Chesapeake Bay in 2016 was 71,600 cfs, about 19 percent (15,100 cfs) below the long-term (1937-2016) annual-mean streamflow of 78,476 cfs (fig. 2).  In 2016, the combined loads from the nine RIM stations were as follows: o Total nitrogen (TN): 157 million pounds (Mlb), 50 Mlb less than the long-term average of 207 Mlb for 1985-2016 (fig. 3).

o Total phosphorus (TP): 9.32 Mlb, 4.16 Mlb less than the long-term average of 13.48 Mlb for 1985-2016 (fig. 4).

o Suspended sediment: 2.51 million tons (Mton), 2.25 Mton less than the long-term average of 4.76 (Mtons) for 1985-2016 (fig. 5). The Chesapeake Bay Program uses the RIM loads and estimates loads from the remaining unmonitored areas to compute a total nutrient and sediment load to the bay. What are the trends in loads delivered to tidal waters from the RIM stations?

Trends in loads from the nine RIM stations are flow-normalized to integrate out the year-to-year variability in river flow; by doing so, changes in nitrogen, phosphorus, and suspended-sediment loads resulting from changing sources, delays associated with storage and transport of historical inputs, and (or) implemented management actions are identified. Changes in loads for nitrogen, phosphorus, and suspended sediment are provided for two time periods: 1985-2016 (long term) and 2007-2016 (short term) (table 1). Loads that are lower in the end year than the start year are classified as improving conditions, while loads that are higher in the end year than the start year are classified as degrading conditions. Loads are classified as having no trend if there is not a discernable difference between start and years.

Changes in total nitrogen loads  Long-term trends in total nitrogen loads indicate improving conditions at the majority of the stations, including the four largest rivers. The Choptank River is the only station whose data indicate degrading conditions. Data from the Appomattox and Pamunkey Rivers indicate no trend.  Short-term trends in total nitrogen loads indicate improving conditions at 4 stations and degrading conditions at 5 stations.

Changes in total phosphorus loads  Long-term trends in total phosphorus loads indicate improving conditions at only 3 stations and degrading conditions at another 5 stations. Data from the Mattaponi River indicate no trend.  Short-term trends in total phosphorus loads indicate improving conditions at only the Patuxent station, degrading conditions at 5 stations, and no trend at the 3 remaining stations.

Changes in suspended-sediment loads  Long-term trends in suspended-sediment loads indicate improving conditions at only 3 stations, degrading conditions at 4 stations, and no trend in conditions at 2 stations.  Short-term trends in suspended-sediment loads indicate improving conditions at only the James station; degrading conditions at 4 stations, and no trend at the remaining 4 stations.

[Improving or degrading trends classified as likelihood estimates greater than or equal to 67 percent]

SUSQUEHANNA RIVER AT CONOWINGO, MD Improving Degrading Degrading Degrading Degrading No trend

POTOMAC RIVER AT WASHINGTON, DC Improving Improving Improving Degrading Improving No Trend

JAMES RIVER AT CARTERSVILLE, VA Improving Improving Improving No Trend Degrading Improving

RAPPAHANNOCK RIVER NR FREDERICKSBURG, VA Improving Improving Degrading No Trend Degrading No Trend

APPOMATTOX RIVER AT MATOACA, VA No Trend Degrading Degrading Degrading No Trend Degrading

PAMUNKEY RIVER NEAR HANOVER, VA No trend Degrading Degrading No trend Degrading Degrading

MATTAPONI RIVER NEAR BEULAHVILLE, VA Improving Degrading No Trend Degrading No Trend No Trend

PATUXENT RIVER NEAR BOWIE, MD Improving Improving Improving Improving Improving Degrading

CHOPTANK RIVER NEAR GREENSBORO, MD Degrading Degrading Degrading Degrading Improving Degrading

What are the patterns in loads and trends across the nontidal monitoring network (2007- 16)?

The USGS computes load and trend results from the NTN to display (1) the range in loads of nitrogen, phosphorus, and suspended sediment; and (2) the trends in these loads. The majority of the NTN sites whose data were used for the analysis had data collected since 2007 (fig. 6 and table 2). To facilitate the comparison of loads and trends between sites, load results from each NTN station are normalized by the respective drainage area to present the results as per-acre loads (also known as yield). The total number of NTN stations analyzed for total nitrogen, total phosphorus, and suspended-sediment load and trends varies because of the length of record and because of the presence or absence of targeted water-quality samples collected during stormflow conditions (see Chanat and others, 2015).

Patterns in total nitrogen loads  Average annual total nitrogen loads, 2007-2016, range from 1.19 to 30.0 pounds per acre (lb/acre; fig. 7) with a combined average load over this period of 6.97 lb/acre.  Half of the NTN stations are improving; while, 31 percent are degrading and the remainder are showing no trends.

o 43 of 86 (50 percent) stations have improving trends, with load reductions ranging from 0.13 to 6.46 lb/acre. o 27 of 86 (31 percent) stations have degrading trends, with load increases ranging from 0.03 to 0.79 lb/acre. o 16 of 86 (19 percent) show no trends.

Patterns in total phosphorus loads  Average annual total phosphorus loads, 2007-2016, range from 0.12 to 2.01 lb/acre (fig. 8) with a combined average load over this period of 0.48 lb/acre.  Just over one-third of the NTN station are improving; while, a quarter are degrading and the remainder are showing no trends.

o 25 of 66 (38 percent) stations have improving trends, with load reductions ranging from 0.02 to 0.53 lb/acre. o 17 of 66 (26 percent) stations have degrading trends, with load increases ranging from 0.01 to 0.59 lb/acre. o 24 of 66 (36 percent) have no trends.

Patterns in suspended-sediment loads  Average annual suspended-sediment loads, 2007-2016, range from 19 to 1,670 lb/acre (fig. 9) with a combined average load over this period of 401 lb/acre.  Less than a quarter of the NTN stations are improving; while, 37 percent are degrading and the remainder are showing no trends.

o 12 of 65 (20 percent) stations have improving trends, with load decreases ranging from 11.2 to 706 lb/acre. o 24 of 65 (37 percent) stations have degrading trends, with load increases ranging from 1.24 to 395 lb/acre. o 29 of 65 (43 percent) have no trends. The Chesapeake Nontidal Monitoring Network and Role of USGS

The Chesapeake Bay Nontidal Water-Quality Monitoring Network is a partnership implemented among the States in the watershed, the U.S. Environmental Protection Agency, the USGS, and the Susquehanna River Basin Commission. A network of monitoring stations has been established and is sampled using standardized protocols and quality-assurance procedures designed to measure pollutant loads and changes in pollutant loads over time. The initial network formed around 1985 with coordinated monitoring at the nine RIM stations. In 2004, the CBP formalized the network, and a period of expansion followed. In 2010 and 2011, the network was further expanded to address the needs of the Total Maximum Daily Load (TMDL). The network currently has 115 sites designed to measure changes in nitrogen, phosphorus, and suspended sediment in the Chesapeake Bay watershed. Through this partnership, nitrogen, phosphorus, and suspended-sediment loads and trends are determined based on (1) continuous streamflow monitoring, (2) extensive water-quality sampling, and (3) advanced statistical analysis. The USGS computes the loads and trends and present this information through this Web site.

References

Chanat, J.G., Moyer, D.L., Blomquist, J.D., Hyer, K.E., and Langland, M.J., 2015, Application of a Weighted Regression Model for Reporting Nutrient and Sediment Concentrations, Fluxes, and Trends in Concentration and Flux for the Chesapeake Bay Nontidal Water-Quality Monitoring Network, Results Through Water Year 2012: U.S. Geological Survey Scientific Investigations Report 2015-5133, 76 p., accessed January 14, 2015 at https://pubs.er.usgs.gov/publication/sir20155133/. Moyer, D.L., Langland, M.J., Blomquist, J.D., and Yang, Guoxiang, 2017, Nitrogen, Phosphorus, and Suspended-Sediment Loads and Trends Measured at the Chesapeake Bay Nontidal Network Stations: Water Years 1985-2016, U.S. Geological Survey Data Release, https://doi.org/10.5066/F7RR1X68.

USGS Contacts

Doug Moyer [email protected] Joel Blomquist [email protected]

USGS Chesapeake Bay Studies: Scott Phillips, [email protected] or visit http://chesapeake.usgs.gov/

O O 76 75 45O CHESAPEAKE BAY WATERSHED BOUNDARY NEW YORK

O 80 NEW YORK 42O Elmira

O 42

O O 78 40 NJ

N A E C D.C. DE Scranton WEST CHESAPEAKE BA C O O I 38 FALL LINE T Y N Chesapeake Bay A L Williamsport T A VIRGINIA 0 50 100 MILES PENNSYLVANIA 0 50 100 KILOMETERS CHESAPEAKE BAY EXPLANATION WATERSHED Physiographic province Altoona BOUNDARY Appalachian Plateau Piedmont Harrisburg Valley and Ridge Coastal Plain Susquehanna t Cr. uine Blue Ridge og od on O C 40 York River

Hagerstown 1

Potomac MARYLAND Baltimore River EXPLANATION 1 WEST River Input Monitoring (RIM) VIRGINIA Shenandoah station and identifier River Annapolis 2 Chester R. 9 8 Patuxent River RIVER INPUT Front Washington, Royal DE NONTIDAL BASINS North Fork D.C.

C Choptank R. Susquehanna River H South Fork E LINE S Harrisonburg A P 4 Potomac E A M Rappahannock River Rappahannock River a River K O t ta E B 80 p o Appomattox River O n 38 Charlottesville i N

Pamunkey River 7 A A VIRGINIA Y E 6 R i Mattaponi River Pa v C m er 3 James un ALL ke F y Y Patuxent River James R ork River iver Richmond C O I Choptank River River River River T Appomattox 5 N A L Base modified from NAD 1983 Albers T Equal-Area Conic Projection Norfolk A

0 10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

Figure 1. Location of the 9 River Input Monitoring (RIM) stations in the Chesapeake Bay watershed. Station numbers and names are provided in table 2. 140,000

120,000

100,000

80,000

60,000

STREAMFLOW, IN CUBIC FEET PER SECOND 40,000

20,000

0 1940 1950 1960 1970 1980 1990 2000 2010 WATER YEAR (OCTOBER - SEPTEMBER) Figure 2. Estimated annual-mean streamflow entering Chesapeake Bay. Black line represents the average annual-mean streamflow of 78,476 cubic feet per second. Source http://md.water.usgs.gov/waterdata/chesinflow/wy/ 400

350

300

250

200

150 LOAD, IN MILLION POUNDS PER YEAR 100

50

0 1985 1990 1995 2000 2005 2010 2015 WATER YEAR (OCTOBER - SEPTEMBER) Figure 3. Combined annual total nitrogen load delivered from the nine River Input Monitoring stations to the Chesapeake Bay. Black line represents the mean annual combined load of 207 million pounds per year. 50

40

30

20 LOAD, IN MILLION POUNDS PER YEAR

10

0 1985 1990 1995 2000 2005 2010 2015 WATER YEAR (OCTOBER - SEPTEMBER) Figure 4. Combined annual total phosphorus load delivered from the nine River Input Monitoring stations to the Chesapeake Bay. Black line represents the mean annual combined load of 13.5 million pounds per year. 25

20

15

10 LOAD, IN MILLION TONS PER YEAR

5

0 1985 1990 1995 2000 2005 2010 2015 WATER YEAR (OCTOBER - SEPTEMBER) Figure 5. Combined annual suspended-sediment load delivered from the nine River Input Monitoring stations to the Chesapeake Bay. Black line represents the mean annual combined load of 4.76 million tons per year. 81o 80o 79o 78o 77o 76o 75o

43o EXPLANATION

83 Nontidal Water-Quality Monitoring station with load and trend results 93 Nontidal Water-Quality Monitoring NY station with load results 6 92 New Nontidal Water-Quality Monitoring 42o station monitoring data only 9 7 10 8 Major Watershed Susquehanna 11 82 Eastern Shore Western Shore 83 12 Potomac 15 41o 14 92 Rappahannock 16 York 17 13 James PA 94 93 19 Base modified from U.S. Geological Survey 95 96 1:2,000,000-scale digital line graphs 20 23 18 Albers Equal-Area ConicProjection 21 97 40o North American Datum of 1983 100 22 98 25 101 24 0 20 40 80 MILES 42 26 27 108 43 99 84 37 86 41 45 55 102 85 30 28 36 111 31 103 40 MD 29 5 109 53 32 104 38 39 44 46 33 106 54 39o 110 113 105 90 89 5 112 87 WV 2 56 114 50 57 34 4 3 51 58 DC 115 35 2 47 60 59 1 49 DE 61 62 71 88 74 63 48 67 38o 72 68 70 75 65 117 VA 76 69 73 64 66 77 81 116 78 79 80

37o

Figure 6. Chesapeake Bay nontidal network. Maroon circles represent stations that were included in the analysis of loads and trends; blue circles represent stations that were included in the analysis of loads only; and stations represented by green circles have fewer than 5 years of monitoring data (no load and trend analysis). Table 2. Chesapeake Bay nontidal monitoring stations. Load computations performed at all stations with a START DATE prior to 2013. Trend computations performed at all stations with START DATE prior to 2008. Bold stations represent the nine River Input Monitoring stations. Stations in red are no longer active. USGS STATION MAJOR Drainage MONITORING DATA MAP ID NUMBER USGS STATION NAME WATERSHED/REGION Area (mi2) START DATE END DATE 1 01487000 NANTICOKE RIVER NEAR BRIDGEVILLE, DE Eastern Shore 75 1998 2016 2 01488500 MARSHYHOPE CREEK NEAR ADAMSVILLE, DE Eastern Shore 47 2005 2016 3 01491000 CHOPTANK RIVER NEAR GREENSBORO, MD Eastern Shore 113 1985 2016 4 01491500 TUCKAHOE CREEK NEAR RUTHSBURG, MD Eastern Shore 85 2005 2016 5 01495000 BIG ELK CREEK AT ELK MILLS, MD Eastern Shore 52 2005 2016 6 01502500 UNADILLA RIVER AT ROCKDALE NY Susquehanna 520 2005 2016 7 01503000 SUSQUEHANNA RIVER AT CONKLIN NY Susquehanna 2,232 2006 2016 8 01515000 SUSQUEHANNA RIVER NEAR WAVERLY NY Susquehanna 4,773 2005 2016 9 01529500 COHOCTON RIVER NEAR CAMPBELL NY Susquehanna 470 2006 2016 10 01531000 CHEMUNG RIVER AT CHEMUNG NY Susquehanna 2,506 2005 2016 11 01531500 SUSQUEHANNA RIVER AT TOWANDA, PA Susquehanna 7,797 1985 2016 82 01534000 TUNKHANNOCK CREEK NEAR TUNKHANNOCK, PA Susquehanna 383 2009 2016 12 01536500 SUSQUEHANNA RIVER AT WILKES-BARRE, PA Susquehanna 9,960 1989 2016 13 01540500 SUSQUEHANNA RIVER AT DANVILLE, PA Susquehanna 11,220 1985 2016 14 01542500 WB SUSQUEHANNA RIVER AT KARTHAUS, PA Susquehanna 1,462 2005 2016 83 01549700 PINE CREEK BL L PINE CREEK NEAR WATERVILLE, PA Susquehanna 944 2007 2016 15 01549760 WB SUSQUEHANNA RIVER AT JERSEY SHORE, PA Susquehanna 5,225 2006 2016 16 01553500 WEST BRANCH SUSQUEHANNA RIVER AT LEWISBURG, PA Susquehanna 6,847 1985 2016 17 01555000 PENNS CREEK AT PENNS CREEK, PA Susquehanna 301 2005 2016 18 01562000 RAYSTOWN BRANCH JUNIATA RIVER AT SAXTON, PA Susquehanna 756 2005 2016 19 01567000 JUNIATA RIVER AT NEWPORT, PA Susquehanna 3,354 1985 2016 20 01568000 SHERMAN CREEK AT SHERMANS DALE, PA Susquehanna 207 2005 2016 21 01570000 CONODOGUINET CREEK NEAR HOGESTOWN, PA Susquehanna 470 2005 2016 22 01571500 YELLOW BREECHES CREEK NEAR CAMP HILL, PA Susquehanna 213 2005 2016 23 01573560 SWATARA CREEK NEAR HERSHEY, PA Susquehanna 483 2005 2016 24 01574000 WEST CONEWAGO CREEK NEAR MANCHESTER, PA Susquehanna 510 2005 2016 25 01576000 SUSQUEHANNA RIVER AT MARIETTA, PA Susquehanna 25,990 1987 2016 26 01576754 CONESTOGA RIVER AT CONESTOGA, PA Susquehanna 470 1985 2016 27 01576787 PEQUEA CREEK AT MARTIC FORGE, PA Susquehanna 148 2005 2016 28 01578310 SUSQUEHANNA RIVER AT CONOWINGO, MD Susquehanna 27,100 1985 2016 84 01578475 OCTORARO CREEK NEAR RICHARDSMERE, MD Susquehanna 177 2007 2016 29 01580520 DEER CREEK NEAR DARLINGTON, MD Western Shore 164 2006 2016 30 01582500 GUNPOWDER FALLS AT GLENCOE, MD Western Shore 160 1985 2016 31 01586000 NORTH BRANCH PATAPSCO RIVER AT CEDARHURST, MD Western Shore 57 1985 2016 32 01589300 GWYNNS FALLS AT VILLA NOVA, MD Western Shore 32 2003 2016 33 01591000 PATUXENT RIVER NEAR UNITY, MD Western Shore 35 1985 2016 34 01594440 PATUXENT RIVER NEAR BOWIE, MD Western Shore 348 1985 2016 35 01594526 WESTERN BRANCH AT UPPER MARLBORO, MD Western Shore 90 2006 2016 36 01599000 GEORGES CREEK AT FRANKLIN, MD Potomac 72 1985 2016 37 01601500 WILLS CREEK NEAR CUMBERLAND, MD Potomac 247 1985 2016 38 01604500 NEAR HEADSVILLE, WV Potomac 221 2006 2016 39 01608500 SOUTH BRANCH POTOMAC RIVER NEAR SPRINGFIELD, WV Potomac 1,461 2006 2016 85 01609000 TOWN CREEK NEAR OLDTOWN, MD Potomac 148 2007 2016 86 01610155 SIDELING HILL CREEK NEAR BELLEGROVE, MD Potomac 102 2007 2016 40 01611500 NEAR GREAT CACAPON, WV Potomac 675 2006 2016 41 01613095 NEAR HANCOCK, MD Potomac 111 2006 2016 42 01613525 LICKING CREEK AT PECTONVILLE, MD Potomac 193 2006 2016 43 01614500 AT FAIRVIEW, MD Potomac 494 1985 2016 44 01616500 NEAR MARTINSBURG, WV Potomac 273 2006 2016 45 01619000 NEAR WAYNESBORO, PA Potomac 93 2006 2016 46 01619500 ANTIETAM CREEK NEAR SHARPSBURG, MD Potomac 281 1985 2016 47 01621050 MUDDY CREEK AT MOUNT CLINTON, VA Potomac 14 1994 2016 48 01626000 SOUTH RIVER NEAR WAYNESBORO, VA Potomac 127 1985 2016 49 01628500 S F NEAR LYNNWOOD, VA Potomac 1,079 1985 2016 50 01631000 S F SHENANDOAH RIVER AT FRONT ROYAL, VA Potomac 1,634 1985 2016 51 01632900 NEAR NEW MARKET, VA Potomac 94 1985 2016 52 01634000 N F SHENANDOAH RIVER NEAR STRASBURG, VA Potomac 770 1985 2016 53 01637500 CATOCTIN CREEK NEAR MIDDLETOWN, MD Potomac 67 1985 2016 54 01638480 CATOCTIN CREEK AT TAYLORSTOWN, VA Potomac 89 1985 2016 55 01639000 AT BRIDGEPORT, MD Potomac 173 1985 2016 56 01646000 NEAR GREAT FALLS, VA Potomac 58 1985 2016 57 01646580 POTOMAC RIVER AT CHAIN BRIDGE, AT WASHINGTON, DC Potomac 11,570 1985 2016 87 01651000 NORTHWEST BR NR HYATTSVILLE, MD Potomac 49 2007 2016 58 01654000 NEAR ANNANDALE, VA Potomac 24 1991 2016 Table 2 cont. Chesapeake Bay nontidal monitoring stations. Load computations performed at all stations with a START DATE prior to 2013. Trend computations performed at all stations with START DATE prior to 2008. Bold stations represent the nine River Input Monitoring stations. Stations in red are no longer active. USGS STATION MAJOR Drainage MONITORING DATA MAP ID NUMBER USGS STATION NAME WATERSHED/REGION Area (mi2) START DATE END DATE 59 01658500 S F NEAR INDEPENDENT HILL, VA Potomac 8 1994 2016 60 01664000 RAPPAHANNOCK RIVER AT REMINGTON, VA Virginia 619 1985 2016 61 01665500 RAPIDAN RIVER NEAR RUCKERSVILLE, VA Virginia 115 2003 2016 62 01667500 RAPIDAN RIVER NEAR CULPEPER, VA Virginia 468 2005 2016 63 01668000 RAPPAHANNOCK RIVER NEAR FREDERICKSBURG, VA Virginia 1,595 1985 2016 64 01671020 NORTH ANNA RIVER AT HART CORNER NEAR DOSWELL, VA Virginia 462 1985 2016 65 01671100 LITTLE RIVER NEAR DOSWELL, VA Virginia 107 2001 2016 66 01673000 PAMUNKEY RIVER NEAR HANOVER, VA Virginia 1,078 1985 2016 67 01673800 PO RIVER NEAR SPOTSYLVANIA, VA Virginia 78 1987 2016 68 01674000 MATTAPONI RIVER NEAR BOWLING GREEN, VA Virginia 256 1985 2016 69 01674500 MATTAPONI RIVER NEAR BEULAHVILLE, VA Virginia 603 1985 2016 70 02011500 BACK CREEK NEAR MOUNTAIN GROVE, VA Virginia 134 1985 2016 71 02015700 BULLPASTURE RIVER AT WILLIAMSVILLE, VA Virginia 110 1985 2016 72 02020500 CALFPASTURE RIVER ABOVE MILL CREEK AT GOSHEN, VA Virginia 141 1999 2016 73 02024752 JAMES RIVER AT BLUE RIDGE PKWY NR BIG ISLAND, VA Virginia 3,076 2006 2016 74 02031000 MECHUMS RIVER NEAR WHITE HALL, VA Virginia 95 1985 2016 75 02034000 AT PALMYRA, VA Virginia 663 1985 2016 76 02035000 JAMES RIVER AT CARTERSVILLE, VA Virginia 6,252 1985 2016 77 02037500 JAMES RIVER NEAR RICHMOND, VA Virginia 6,753 1985 2016 78 02039500 APPOMATTOX RIVER AT FARMVILLE, VA Virginia 302 1985 2016 79 02041000 DEEP CREEK NEAR MANNBORO, VA Virginia 158 1991 2016 80 02041650 APPOMATTOX RIVER AT MATOACA, VA Virginia 1,342 1985 2016 81 02042500 CHICKAHOMINY RIVER NEAR PROVIDENCE FORGE, VA Virginia 251 1985 2016

Table 2. New Chesapeake Bay nontidal monitoring stations added since 2011. USGS STATION MAJOR Drainage MONITORING DATA MAP ID NUMBER USGS STATION NAME WATERSHED/REGION Area (mi2) START DATE END DATE 88 01486000 MANOKIN BRANCH NEAR PRINCESS ANNE, MD Eastern Shore 5 2011 2016 89 01493112 CHESTERVILLE BRANCH NEAR CRUMPTON, MD Eastern Shore 6 2011 2016 90 01493500 MORGAN CREEK NEAR KENNEDYVILLE, MD Eastern Shore 13 2011 2016 91 01511500 TIOUGHNIOGA RIVER AT ITASKA, NY Susquehanna 730 2012 2014 92 01553700 CHILLISQUAQUE CREEK AT WASHINGTONVILLE, PA Susquehanna 51 2013 2016 93 01555500 EAST MAHANTANGO CREEK NEAR DALMATIA, PA Susquehanna 162 2012 2016 94 01565000 KISHACOQUILLAS CREEK AT REEDSVILLE, PA Susquehanna 164 2012 2016 95 01571005 PAXTON CREEK NEAR GLENNWOOD, PA Susquehanna 11 2013 2016 96 01573160 QUITTAPAHILLA CREEK NEAR BELLEGROVE Susquehanna 74 2013 2016 97 01573695 CONEWAGO CREEK NEAR BELLAIRE, PA Susquehanna 21 2013 2016 98 01573710 CONEWAGO CREEK NEAR FALMOUTH, PA Susquehanna 48 2011 2016 99 01575585 CODORUS CREEK NEAR PLEASUREVILLE, PA Susquehanna 267 2013 2016 100 15765195 BIG SPRING RUN NEAR MYLIN CORNERS, PA Susquehanna 2 2011 2016 101 01576767 PEQUEA CREEK NEAR RONKS, PA Susquehanna 70 2013 2016 102 01577500 MUDDY CREEK AT CASTLE FIN, PA Susquehanna 133 2015 2016 103 01581752 PLUMTREE RUN NEAR BEL AIR, MD Western Shore 3 2013 2016 104 0158175320 WHEEL CREEK NEAR ABINGDON, MD Western Shore 1 2011 2016 105 01593500 LITTLE PATUXENT RIVER AT GUILFORD, MD Western Shore 38 2011 2016 106 01595300 ABRAM CREEK AT OAKMONT, WV Potomac 43 2013 2016 107 01601100 WILLS CREEK AT ELLERSLIE, MD Potomac 185 2012 2014 108 01613030 WARM SPRINGS RUN NEAR BERKELEY SPRINGS, WV Potomac 7 2011 2016 109 01614000 BACK CREEK NEAR JONES SPRINGS, WV Potomac 235 2012 2016 110 01616400 MILL CREEK AT BUNKER HILL, WV Potomac 18 2011 2016 111 01618100 ROCKYMARSH RUN AT SCRABBLE, WV Potomac 16 2011 2016 112 01636500 SHENANDOAH RIVER AT MILLVILLE, WV Potomac 3041 2013 2016 113 01648000 ROCK CREEK AT SHERILL DRIVE AT WASHINGTON, DC Potomac 62 2013 2016 114 01651770 HICKEY RUN AT NEW YORK AVENUE AT WASHINGTON, DC Potomac 1 2013 2016 115 01651800 WATTS BRANCH AT WASHINGTON, DC Potomac 3 2013 2016 116 01669520 DRAGON SWAMP AT MASCOT, VA Virginia 109 2011 2016 117 01674182 POLECAT CREEK AT ROUTE 301 NEAR PENOLA, VA Virginia 49 2013 2016 81o 80o 79o 78o 77o 76o 75o

EXPLANATION 43o Trend Direction, 2007-2016 ! No Trend

NY

# Improving #

# "

Degrading #"

# # " 42o Average Load, 2007-2016 (pounds per acre) "!" " 1.19 - 6.33 "! " 6.34 - 12.67 " 12.68 - 30.03 "# #

"! "

"! Major Watershed # 41o " #" Susquehanna "# PA

Eastern Shore

Western Shore "#

# #

Potomac #

" # "

"! ""

Rappahannock #

" # " # York #

40o ""

James # # #

# # # #

"# " " "#

" # "# " "# "

" # " #

! " #

Base modified from U.S. Geological Survey # " # "

#

" ""! # " 1:2,000,000-scale digital line graphs " "" MD # Albers Equal-Area ConicProjection " North American Datum of 1983 "# "#

WV

0 20 40 60 80 MILES # #

# ! # ! #"

"! """ " " # " # 39o " " #" "! DC #"

"# "#

"# DE #

# #

" # " # VA " " " "! "! "#

"# "# "#

# ! #

38o " ""! " # "# " "# "#

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37o

Figure 7. Total nitrogen per acre loads and trends in loads, 2007-16, for selected monitoring stations. 81o 80o 79o 78o 77o 76o 75o

43o EXPLANATION Trend Direction, 2007-2016

! No Trend NY

#

Improving "#

#

# Degrading "

#

# o ""# " 42 Average Load, 2007-2016 (pounds per acre) ! " 0.12 - 0.38 " " 0.39 - 0.75

"

0.76 - 2.01 "# # #"

"# "

o Major Watershed # ! 41 # " " Susquehanna " PA

Eastern Shore

Western Shore "# Potomac "! # "! "# ""! Rappahannock "! "#

York

40o "#"#

James #

"! "#"! "# " ! "! #

"! " ""#! "

# !

! " #

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#

" "" # " 1:2,000,000-scale digital line graphs " "" MD # Albers Equal-Area ConicProjection "

North American Datum of 1983 "#

WV # 0 20 40 60 80 MILES # " ! " #"#" o "! "#" 39 "! #" DC "!

DE "# ! VA "

# 38o "! "

"!

! # " " "! "! "#

37o

Figure 8. Total phosphorus per acre loads and trends in loads, 2007-16, for selected monitoring stations. 81o 80o 79o 78o 77o 76o 75o

43o EXPLANATION Trend Direction, 2007-2016

! No Trend NY # Improving "!

# Degrading #"

#

# 42o ""# " Average Load, 2007-2016 (pounds per acre) "! " 19 - 365

" 366 - 729 " 730 - 1,670 #" #" "! Major Watershed 41o "! #" Susquehanna "# PA Eastern Shore

Western Shore "! Potomac "# "! "! "!"#

Rappahannock

"! # " # York 40o ""!

James # "! ! # #

"# ! ""! " "! "!" "

"! "#

! " # Base modified from U.S. Geological Survey # " "# "# ! # " 1:2,000,000-scale digital line graphs "" "! "#" MD Albers Equal-Area ConicProjection "! North American Datum of 1983 "#

WV 0 20 40 60 80 MILES # " ! # "! #" o "# "! " " 39 "# #" DC "!

DE "# ! VA "

!

38o "# " # "# " "# "! "! "#

37o

Figure 9. Suspended-sediment per acre loads and trends in loads, 2007-16, for selected monitoring stations.