Throughout the world, human activities have increased the discharges of sediments and plant nutrients from watersheds.  These materials are essential for all life, but cause environmental problems when overabundant.  Excess nutrients released by agriculture, industry, and residential areas pollute and damage streams, rivers, lakes, and coastal waters.  Watershed scientists study how landscape characteristics, ecosystem processes, and human activities interact to control material discharges in streams.  Such information is essential to understand and solve water pollution problems.

SERC has been at the forefront of watershed research for decades and has had a unique focus on exploring how the flow of water and materials link the land and the sea.  To study the factors controlling nutrient transport, we use data from hundreds of study sites throughout the Chesapeake Bay watershed, including more than 40 years of data from sites at SERC's home in the Rhode River watershed. We use a geographic information system (GIS) to organize and summarize mapped data on watershed characteristics, weather, and nutrient inputs.  Then we apply statistical, mathematical, and computer simulation models to relate those characteristics to measured nutrient losses.

We were among the first to clearly document differences among physiographic provinces in the amounts of nutrients lost from specific land uses, such as cropland.  We also published pioneering work in relating the net human inputs of nitrogen and phosphorus to watersheds with the losses of those materials in streams and rivers.  SERC has also been a leader in studying how stream side forests and wetlands (riparian buffers) can reduce watershed discharges by trapping pollutants released by uphill land uses (see Riparian Buffers project).

Relating Watershed Discharges to Watershed Characteristics

Jordan, Thomas E., Weller, Donald E. and Pelc, Carey E. (2017). Effects of Local Watershed Land Use on Water Quality in Mid-Atlantic Coastal Bays and Subestuaries of the Chesapeake Bay. Estuaries and Coasts, , 1-16. http://dx.doi.org/10.1007/s12237-017-0303-5

Xia, Yongqiu, Weller, Donald E., Williams, Meghan N., Jordan, Thomas E. and Yan, Xiaoyuan. 2016. Using Bayesian hierarchical models to better understand nitrate sources and sinks in agricultural watersheds. Water research, 105: 527-539. doi:10.1016/j.watres.2016.09.033

Weller, Donald E. and Baker, Matthew E. 2014. Cropland Riparian Buffers throughout Chesapeake Bay Watershed: Spatial Patterns and Effects on Nitrate Loads Delivered to Streams. JAWRA Journal of the American Water Resources Association, 50(3): 696-712. doi:10.1111/jawr.12207

Bain, Daniel J., Green, Mark B., Campbell, John L., Chamblee, John F., Chaoka, Sayo, Fraterrigo, Jennifer M., Kaushal, Sujay S., Martin, Sherry L., Jordan, Thomas E., Parolari, Anthony J., Sobczak, William V., Weller, Donald E., Wolheim, Wilfred M., Boose, Emery R., Duncan, Jonathan M., Gettel, Gretchen M., Hall, Brian R., Kumar, Praveen, Thompson, Jonathan R., Vose, James M., Elliott, Emily M. and Leigh, David S. 2012. Legacy Effects in Material Flux: Structural Catchmen Changes Predate Long-Term Studies. Bioscience, 62(6): 575-584. doi:10.1525/bio.2012.62.6.8

Weller, Donald E., Jordan, Thomas E., Sellner, K. G., Foreman, K., Shenk, K., Tango, P., Phillips, S. W. and Dubin, M. 2010. Small Watershed Monitoring Designs: A Report from the Chesapeake Bay Program Scientific and Technical Advisory Committee 18 pages.

Boomer, K. B., Weller, Donald E. and Jordan, Thomas E. 2008. Empirical models based on the Universal Soil Loss Equation fail to predict sediment discharges from Chesapeake Bay catchments. Journal of Environmental Quality, 37: 79-89. doi:10.1007/s10533-008-9212-9

Breitburg, Denise L., Hines, Anson H., Jordan, Thomas E., McCormick, Melissa K., Weller, Donald E. and Whigham, Dennis F. 2008. Landscape patterns, nutrient discharges, and biota of the Rhode River estuary and its watershed: Contribution of the Smithsonian Environmental Research Center to the Pilot Integrated Ecosystem Assessment Edgewater, Maryland: Smithsonian Environmental Research Center. 87 pages.

Russell, Marc J., Weller, Donald E., Jordan, Thomas E., Sigwart, Kevin J. and Sullivan, Kathryn J. 2008. Net anthropogenic phosphorus inputs: spatial and temporal variability in the Chesapeake Bay region. Biogeochemistry, 88(3): 285-304. doi:10.1007/s10533-008-9212-9

Baker, M. E., Weller, Donald E. and Jordan, Thomas E. 2006. Comparison of automated watershed delineations: effects on land cover areas, percentages, and relationships to nutrient discharge. Photogrammetric Engineering and Remote Sensing, 72: 159-168.

Boesch, D. F., Cohn, T. A., Eshelman, K. N., Grizzard, T. J., Hamertt, J. M., Prestegaard, K. L., Staver, K. W. and Weller, Donald E. 2005. Assessing progress and effectiveness through monitoring streams and rivers Edgewater, MD: Chesapeake Research Consortium. (Science and Advisory Committee of the Chesapeake Bay Program (STAC) Publication 05-005; ) 31 pages.

Jordan, Thomas E., Weller, Donald E. and Correll, David L. 2003. Sources of nutrient inputs to the Patuxent River estuary. Estuaries, 26: 226-243.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 2000. Transfer of Phosphorus from the farm to the Bay. In: Agriculture and Phosphorus management: the Chesapeake Bay. Boca Raton, FL: Lewis Publishers, pp.131-144.

Jordan, Thomas E., Correll, David L. and Weller, Donald E. 2000. "Mattawoman creek watershed nutrient and sediment dynamics: final contract report to Charles County, Maryland". Edgewater, MD: Smithsonian Environmental Research Center, 1-73. (https://repository.si.edu/handle/10088/15578).

Liu, Zhi-Jun, Weller, Donald E., Correll, David L. and Jordan, Thomas E. 2000. Effects of land cover and geology on stream chemistry in watersheds of Chesapeake Bay. Journal of the American Water Resources Association, 36(6): 1349-1363.

Correll, David L. and Weller, Donald E. 1997. Nitrogen input-output budgets for forests in the Chesapeake Bay watershed. Pensacola, FL: SETAC Press.

Jordan, Thomas E., Correll, David L. and Weller, Donald E. 1997. Effects of agriculture on discharges of nutrients from Coastal Plain watersheds of Chesapeake Bay. Journal of Environmental Quality, 26(3): 836-848.

Jordan, Thomas E., Correll, David L. and Weller, Donald E. 1997. Relating nutrient discharges from watersheds to land use and streamflow variability. Water Resources Research, 33(11): 2579-2590.

Jordan, Thomas E., Correll, David L. and Weller, Donald E. 1997. Nonpoint source discharges of nutrients from Piedmont watersheds of Chesapeake Bay. Journal of the American Water Resources Association, 33(3): 631-645.

Jordan, Thomas E. and Weller, Donald E. 1996. Human contributions to terrestrial nitrogen flux. Bioscience, 46(9): 655-664.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1995. Livestock and pasture land effects on the water quality of Chesapeake Bay watershed streams. In: Steele, Kenneth, Animal Waste and the Land-Water Interface. New York: Lewis Publishers, pp.107-117.

Jordan, Thomas E., Correll, David L., Weller, Donald E. and Goff, Nancy M. 1995. Temporal variation in precipitation chemistry on the shore of the Chesapeake Bay. Water, Air and Soil Pollution, 83: 263-284.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1994. Chesapeake Bay watershed: Effects of land use and geology on dissolved nitrogen concentrations. In: Hill, Paula and Nelson, Steve, Toward a sustainable coastal watershed: The Chesapeake experiment. Chesapeake Research Consortium. Edgewater, MD: Chesapeake Research Consortium, pp.639-648.

Simulation Models of Water and Nutrient Discharges from Watersheds

Sharifi, Amirreza, Yen, Haw, Boomer, Kathleen M. B., Kalin, Latif, Li, Xuyong and Weller, Donald E. 2017. Using multiple watershed models to assess the water quality impacts of alternate land development scenarios for a small community. Catena, 150: 87-99. doi:10.1016/j.catena.2016.11.009

Weller, D. E., Friedrichs, M., Najjar, R., Paolisso, M., Pascual, p., Shenk, G. and Sellner, K. 2014. Multiple Models for Management in the Chesapeake Bay. STAC Publication Number 14-004 Edgewater, Maryland: Chesapeake Research Consortium.

Boomer, Kathleen M. B., Weller, Donald E., Jordan, Thomas E., Linker, Lewis, Liu, Zhi-Jun, Reilly, James, Shenk, Gary and Voinov, Alexey A. 2013. Using Multiple Watershed Models to Predict Water, Nitrogen, and Phosphorus Discharges to the Patuxent Estuary. JAWRA Journal of the American Water Resources Association, 49(1): 15-39. doi:10.1111/j.1752-1688.2012.00689.x

Li, Xuyong, Weller, Donald E. and Jordan, Thomas E. 2010. Watershed model calibration using multi-objective optimization and multi-site averaging. Journal of Hydrology, 380(3-4): 277-288. doi:10.1016/j.jhydrol.2009.11.003

Liu, Zhi-Jun and Weller, Donald E. 2008. A stream network model for integrated watershed modeling. Environmental Modeling & Assessment, 13: 291-303. doi:10.1007/s10666-007-9083-9

Liu, Zhi-Jun, Weller, Donald E., Jordan, Thomas E., Correll, David L. and Boomer, K. B. 2008. Integrated modular modeling of water and nutrients from point and nonpoint sources in the Patuxent River watershed. Journal of the American Water Resources Association, 44: 700-703. doi:10.1111/j.1752-1688.2008.00200.x

Sanford, L., Cerco, C., Duffy, C., Gross, T., Kemp, M., Linker, L., Wang, H., Weller, Donald E. and Wood, Bernard. 2006. Modeling in the Chesapeake Bay Program: 2010 and beyond Edgewater, MD: Chesapeake Bay Program Scientific and Technical Advisory Committee. (Science and Advisory Committee of the Chesapeake Bay Program (STAC) Publication 06-001; ) 38 pages.

Weller, Donald E., Jordan, Thomas E., Correll, David L. and Liu, Zhi-Jun. 2003. Effects of land-use change on nutrient discharges from the Patuxent River watershed. Estuaries, 26: 244-266.

Lee, K. Y., Fisher, T. R., Jordan, Thomas E., Correll, David L. and Weller, Donald E. 2000. Modeling the hydrochemistry of the Choptank River Basin using GWLF and Arc/Info: 1. Model calibration and validation. Biogeochemistry, 49(2): 143-173.

Long-term Studies of the Rhode River Watershed

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 2001. Effects of precipitation and air temperature on organic carbon discharges from Rhode River watersheds. Water, Air and Soil Pollution, 28: 139-159.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 2000. Dissolved silicate dynamics of the Rhode River watershed and estuary. Estuaries, 23(2): 188-198.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 2000. Beaver pond biogeochemical effects in the Maryland Coastal Plain. Biogeochemistry, 49: 217-239.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1999. Effects of precipitation and air temperature on nitrogen discharges from Rhode River watersheds. Water, Air, & Soil Pollution, 115(1): 547-575.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1999. Effects of interannual variation of precipitation on stream discharge from Rhode River subwatersheds. Journal of the American Water Resources Association, 35(1): 73-82.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1999. Effects of precipitation and air temperature on Phosphorus fluxes from Rhode River watersheds. Journal of Environmental Quality, 28(1): 144-154.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1999. Transport of Nitrogen and Phosphorus from Rhode River watersheds during storm events. Water Resources Research, 35(8): 2513-2521.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1999. Precipitation effects on sediment and associated nutrient discharges from Rhode River watersheds. Journal of Environmental Quality, 28: 1897-1907.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1994. Long-term nitrogen deposition on the Rhode River watershed. Edgewater, MD: Chesapeake Research Consortium.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1992. Cross media inputs to eastern US watersheds and their significance to estuarine water quality. Water Science and Technology, 26(12): 2675-5683.

Correll, David L., Jordan, Thomas E. and Weller, Donald E. 1992. Nutrient flux in a landscape: Effects of coastal land use and terrestrial community mosaic on nutrient transport to coastal waters. Estuaries, 15(4): 431-432.

Jordan, Thomas E., Correll, David L., Miklas, Joseph J. and Weller, Donald E. 1991. Nutrients and chlorophyll at the interface of a watershed and an estuary. Limnology and Oceanography, 36: 251-267.

Jordan, Thomas E., Correll, David L., Miklas, Joseph J. and Weller, Donald E. 1991. Long-term trends in estuarine nutrients and chlorophyll, and short-term effects of variation in watershed discharge. Marine Ecology Progress Series, 75: 121-132.

Jordan, Thomas E., Correll, David L., Peterjohn, William T. and Weller, Donald E. 1986. Nutrient flux in a landscape: The Rhode River watershed and receiving waters. In: Correll, David L., Watershed Reserch Perspectives. Washington, DC: Smithsonian Institution Press, pp.57-76.

Weller, Donald E., Peterjohn, William T., Goff, Nancy M. and Correll, David L. 1986. Ion and acid budgets for a forested Atlantic Coastal Plain watershed and their implications for the impacts of acid deposition. In: Correll, David L., Watershed Research Perspectives. Washington, DC: Smithsonian Institution Press, pp.392-42l.