Abstract
We evaluated the accuracy of six watershed models of nitrogen export in streams (kg km2 yr−1) developed for use in large watersheds and representing various empirical and quasi-empirical approaches described in the literature. These models differ in their methods of calibration and have varying levels of spatial resolution and process complexity, which potentially affect the accuracy (bias and precision) of the model predictions of nitrogen export and source contributions to export. Using stream monitoring data and detailed estimates of the natural and cultural sources of nitrogen for 16 watersheds in the northeastern United States (drainage sizes = 475 to 70,000 km2), we assessed the accuracy of the model predictions of total nitrogen and nitrate-nitrogen export. The model validation included the use of an error modeling technique to identify biases caused by model deficiencies in quantifying nitrogen sources and biogeochemical processes affecting the transport of nitrogen in watersheds. Most models predicted stream nitrogen export to within 50% of the measured export in a majority of the watersheds. Prediction errors were negatively correlated with cultivated land area, indicating that the watershed models tended to over predict export in less agricultural and more forested watersheds and under predict in more agricultural basins. The magnitude of these biases differed appreciably among the models. Those models having more detailed descriptions of nitrogen sources, land and water attenuation of nitrogen, and water flow paths were found to have considerably lower bias and higher precision in their predictions of nitrogen export.
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References
Alexander RB, Smith RA & Schwarz GE (2000) Effect of stream channel size on the delivery of nitrogen to the Gulf of Mexico. Nature 403: 758–761
Alexander RB, Smith RA, Schwarz GE, Preston SD, Brakebill JW, Srinivasan R & Pacheco PA (2001) Atmospheric nitrogen flux from the watersheds of major estuaries of the United States: An application of the SPARROW watershed model. In: Valigura R, Alexander R, Castro M, Meyers T, Paerl H, Stacey P & Turner RE (Eds) Nitrogen Loading in Coastal Water Bodies: An Atmospheric Perspective, American Geophysical UnionMonograph 57, pp 119–170
Beaulac MN & Reckhow KH (1982) An examination of land use - nutrient export relationships. Wat. Res. Bull. 18: 1013–1024
Behrendt H (1996) Inventories of point and diffuse sources and estimated nutrient loads - a comparison for different river basins in central Europe. Water Sci. Tech. 33: 99–107
Bicknell BR, Imhoff JC, Kittle JL Jr., Donigian AS Jr & Johanson RC (1997) Hydrological simulation program - fortran user's manual for release 11. U.S. Environmental Protection Agency, Environmental Research Laboratory, Athens, Georgia, U.S.A. EPA/600/R- 97/080
Boyer EW, Goodale CL, Jaworski NA & Howarth RW(2002) Anthropogenic nitrogen sources and relationships to riverine nitrogen export in the northeastern U.S.A. Biogeochemistry 57/58: 137–169
Caraco NF & Cole JJ (1999) Human impact on nitrate export: An analysis using major world rivers. Ambio. 28: 167–170
Castro MS, Driscoll C, Jordan TE, Reay W, Seitzinger S, Stiles R & Cable J (2001) Assessment of the contribution made by atmospheric nitrogen deposition to the total nitrogen load to thirty-four estuaries on the Atlantic and Gulf coasts of the United States, In: Valigura R, Alexander R, Castro M, Meyers T, Paerl H, Stacey P & Turner RE (Eds) Nitrogen Loading in Coastal Water Bodies: An Atmospheric Perspective, American Geophysical Union Monograph 57, pp 77–106
Cohn TA, DeLong LL, Gilroy EJ, Hirsch RM & Wells DK (1989) Estimating constituent loads. Wat. Resour. Res. 25: 937–942
Cunnane C (1978) Unbiased plotting positions - a review. J. Hydrology 37: 205–222
Delwiche LL & Haith DA (1983) Loading functions for predicting nutrient losses from complex watersheds. Water Resour. Bul. 19: 951–959
Fisher DC & Oppenheimer M (1991) Atmospheric nitrogen deposition and the Chesapeake Bay estuary. Ambio. 20: 102–108
Frink CR (1991) Estimating nutrient exports to estuaries. J. Environ. Qual. 20: 717–724
Galloway JN, Levy II H & Kasibhatla PS (1994) Year 2020: consequences of population growth and development on the deposition of oxidized nitrogen. Ambio. 23: 120–123
Haith DA & Shoemaker LL (1987) Generalized watershed loading functions for stream flow nutrients. Water Resources Bulletin 23: 471–478
Hill AR (1996) Nitrate removal in stream riparian zones. J. Envir. Qual. 25: 743–755
Howarth RW (1998) An assessment of human influences on fluxes of nitrogen from the terrestrial landscape to the estuaries and continental shelves of the North Atlantic Ocean. Nutrient Cycling in Agroecosystems 00: 1–11
Howarth RW, Billen G, Swaney D, Townsend A, Jaworski N, Lajtha K, Downing JA, Elmgren R, Caraco N, Jordan T, Berendse F, Freney J, Kudeyarov V, Murdoch P & Zhu Zhao-liang (1996) Regional nitrogen budgets and riverine N & P fluxes for the drainages to the North Atlantic Ocean: natural and human influences. Biogeochem. 35: 75–139
Howarth RW, Fruci JR & Sherman D (1991) Inputs of sediment and carbon to an estuarine ecosystem: Influence of land use. Ecological Applications 1: 27–39
Jaworski NA, Groffman PM, Keller AA & Prager JC (1992) A watershed nitrogen and phosphorus balance: the Upper Potomac River basin. Estuaries 15: 83–95
Jaworski NA, Howarth RW & Hetling LJ (1997) Atmospheric deposition of nitrogen oxides onto the landscape contributes to coastal eutrophication in the northeast United States. Environ. Sci. Techno. 31: 1995–2004
Johnes PJ (1996) Evaluation and management of the impact of land use change on the nitrogen and phosphorus load delivered to surface waters: the export coefficient modelling approach. J. of Hydrology 183: 323–349
Johnes PJ & Heathwaite AL (1997) Modelling the impact of land use change on water quality in agricultural catchments. Hydrological Processes 11: 269–286
Johnes PJ, Moss B & Phillips GL (1996) The determination of water quality by land use, livestock numbers and population data - testing of a model for use in conservation and water quality management. Freshwater Biology 36: 951–473
Johnson DW (1992) Nitrogen retention in forest soils. J. Envir. Qual. 21: 1–12
Jordan TE & Weller DE (1996) Human contributions to terrestrial nitrogen flux: assessing the sources and fates of anthropogenic fixed nitrogen. Bioscience 46: 655–664
Kelly CA, Rudd JWM, Hesslein RH, Schindler DW, Dillon PJ, Driscoll CT, Gherini SA & Hecky RE (1987) Prediction of biological acid neutralization in acid-sensitive lakes. Biogeochem. 3: 129–141
Lee KY, Fisher TR, Jordan TE, Correll DL & Weller DE (2000) Modeling the hydrochemistry of the Choptank River Basin using GWLF and Arc/Info: 1. Model calibration and validation. Biogeochem. 49: 143–173
Lewis WM Jr, Melack JM, McDowell WH, McClain M & Richey JE (1999) Nitrogen yields from undisturbed watersheds in the Americas. Biogeochemistry 46: 149–162
Lewis WM Jr (2002) Yield of nitrogen from minimally disturbed watersheds of the United States. Biogeochemistry 57/58: 375–385
McBride GB, Alexander RB, Elliot AH & Shankar U (2000) Regional scale modelling of water quality. Water and Atmosphere, Vol. 8 (pp 29–31). National Institute of Water and Atmospheric Research (NIWA), Auckland, New Zealand
Meybeck M (1982) Carbon, nitrogen and phosphorus transport by world rivers. Amer. J. of Sci. 282: 401–450
Molot LA & Dillon PJ (1993) Nitrogen mass balances and denitrification rates in central Ontario Lakes. Biogeochem. 20: 195–212
Montgomery DC & Peck EA (1982) Introduction to linear regression analysis. John Wiley & Sons, New York, NY
National Research Council (2000) Clean coastal waters: Understanding and reducing the effects of nutrient pollution, Ocean Studies Board and Water Science and Technology board, National Academy of Sciences, Washington, DC
Nixon SW (1995) Coastal marine eutrophication: a definition, social causes, and future concerns. Ophelia 41: 199–219
Parton WJ, Stewart JWB & Cole CV (1988) Dynamics of C, N, P, and S in grassland soils: a model. Biogeochem. 5: 109–131
Peierls BL, Caraco NF, Pace ML & Cole JJ (1991) Human influence on river nitrogen. Nature 350: 386–387
Preston SD & Brakebill JW (1999) Application of spatially referenced regression modeling for the evaluation of total nitrogen loading in the Chesapeake Bay watershed. U.S. Geological Survey Water Resources Investigations Report 99-4054
Rastetter EB, King AW, Cosby BJ, Hornberger GM, O'Neill RV & Hobbie JE (1992) Aggregating fine-scale ecological knowledge to model coarser-scale attributes of ecosystems. Ecological Apps. 2: 55–70
Sauer TJ, Alexander RB, Brahana JV & Smith RA (in press) The importance and role of watersheds in the transport of nitrogen. In: Follett, RF & JL Hatfield (Eds) Nitrogen in the Environment: Sources, Problems, and Management. Elsevier Science Publishers, the Netherlands
Seitzinger SP & C Kroeze (1998) Global distribution of nitrous oxide production and N inputs in freshwater and coastal marine ecosystems. Global Biogeochem. Cycles 12: 93–113
Seitzinger SP, Renee VS, Boyer EA, Alexander RB, Billen G, Howarth RW, Bernhard MB & van Breemen N (2002) Nitrogen retention in rivers: Model development and application to watersheds in the northeastern U.S.A. Biogeochemistry 57/58: 199–237
Smith RA, GE Schwarz & RB Alexander (1997) Regional interpretation of water-quality monitoring data. Wat. Resour. Res. 33: 2781–2798
Srinivasan R, Arnold JG, Muttiah RS, Walker D & Dyke PT (1993) Hydrologic unit modeling of the United States (HUMUS). In: Yang S (Ed) Advances in Hydro-Science and Engineering, Vol. I, Part A (pp 451–456). Washington, D.C., U.S.A.
Stacy PE, Greening HS, Kremer JN, Peterson D & Tomasko DA (2001) Contributions of atmospheric nitrogen deposition to U.S. estuaries: Summary and conclusions. In: Valigura R, Alexander R, Castro M, Meyers T, Paerl H, Stacey P & Turner RE (Eds) Nitrogen Loading in Coastal Water Bodies: An Atmospheric Perspective, American Geophysical Union Monograph 57, pp 187–226
Thomann (1972) Systems analysis and water quality management. Environmental Research and Applications, Inc., New York, NY
United States Environmental Protection Agency (1980) Design manual: Onsite wastewater treatment and disposal systems. Office of Water Programs Operations, Washington, DC, EPA 625/1-80-012
Van Breemen N, Boyer EW, Goodale CL, Jaworski NA, Paustian K, Seitzinger SP, Lajtha K, Mayer B, van Dam D, Howarth RW, Nadelhoffer KJ, Eve M, & Billen G (2002) Where did all the nitrogen go? Fate of nitrogen inputs to large watersheds in the northeastern U.S.A. Biogeochemistry 57/58: 267–293
Vitousek PM, Aber JD, Howarth RW, Likens GE, Matson PA, Schindler DW, Schlesinger WH & Tilman DG (1997) Human alteration of the global nitrogen cycle: sources and Consequences. Ecological Applications 7: 737–750
Whitehead PG, Wilson EJ & Butterfield D (1998) A semi-distributed Integrated Nitrogen model for multiple source assessment in Catchments (INCA): Part I - model structure and process equations. Sci. of the Total Environ. 210/211: 547–558
Young RA, Onstad CA & Bosch DD (1995) AGNPS: An agricultural nonpoint source model. In: Singh VP (Ed) Computer Models of Watershed Hydrology. Water Resource Publications, Highlands Ranch, Colorado
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Alexander, R.B., Johnes, P.J., Boyer, E.W. et al. A comparison of models for estimating the riverine export of nitrogen from large watersheds. Biogeochemistry 57, 295–339 (2002). https://doi.org/10.1023/A:1015752801818
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DOI: https://doi.org/10.1023/A:1015752801818