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“Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models” by Dale M. Robertson and David A. Saad

Authors

  • R. Peter Richards,

    1. Senior Research Scientist (Richards), Director Emeritus (Baker), and Research Scientist (Confesor), National Center for Water Quality Research, Heidelberg University, 310 E. Market Street, Tiffin, Ohio 44883
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  • Ibrahim Alameddine,

    1. Postdoctoral Fellow (Alameddine) and Professor (Allan, Scavia), School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan; Assistant Professor (Bosch), Science Department, Grace College, Winona Lake, Indiana
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  • J. David Allan,

    1. Postdoctoral Fellow (Alameddine) and Professor (Allan, Scavia), School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan; Assistant Professor (Bosch), Science Department, Grace College, Winona Lake, Indiana
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  • David B. Baker,

    1. Senior Research Scientist (Richards), Director Emeritus (Baker), and Research Scientist (Confesor), National Center for Water Quality Research, Heidelberg University, 310 E. Market Street, Tiffin, Ohio 44883
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  • Nathan S. Bosch,

    1. Postdoctoral Fellow (Alameddine) and Professor (Allan, Scavia), School of Natural Resources and Environment, University of Michigan, Ann Arbor, Michigan; Assistant Professor (Bosch), Science Department, Grace College, Winona Lake, Indiana
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  • Remegio Confesor,

    1. Senior Research Scientist (Richards), Director Emeritus (Baker), and Research Scientist (Confesor), National Center for Water Quality Research, Heidelberg University, 310 E. Market Street, Tiffin, Ohio 44883
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  • Joseph V. DePinto,

    1. Senior Scientist (DePinto), LimnoTech, Ann Arbor, Michigan; Associate Professor (Dolan), Department of Natural and Applied Sciences, University of Wisconsin – Green Bay, Wisconsin; Director (Reutter), Ohio Sea Grant College Program and Stone Lab, The Ohio State University, Columbus, Ohio
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  • David M. Dolan,

    1. Senior Scientist (DePinto), LimnoTech, Ann Arbor, Michigan; Associate Professor (Dolan), Department of Natural and Applied Sciences, University of Wisconsin – Green Bay, Wisconsin; Director (Reutter), Ohio Sea Grant College Program and Stone Lab, The Ohio State University, Columbus, Ohio
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  • Jeffrey M. Reutter,

    1. Senior Scientist (DePinto), LimnoTech, Ann Arbor, Michigan; Associate Professor (Dolan), Department of Natural and Applied Sciences, University of Wisconsin – Green Bay, Wisconsin; Director (Reutter), Ohio Sea Grant College Program and Stone Lab, The Ohio State University, Columbus, Ohio
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  • Donald Scavia

    1. Senior Scientist (DePinto), LimnoTech, Ann Arbor, Michigan; Associate Professor (Dolan), Department of Natural and Applied Sciences, University of Wisconsin – Green Bay, Wisconsin; Director (Reutter), Ohio Sea Grant College Program and Stone Lab, The Ohio State University, Columbus, Ohio
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  • Discussion No. JAWRA-11-0147-D of the Journal of the American Water Resources Association (JAWRA).

  • Paper No. JAWRA-10-0172-P of the Journal of the American Water Resources Association (JAWRA) 47(5):1011-1033.

(E-Mail/Richards: prichard@heidelberg.edu).

Abstract

Richards, R. Peter, Ibrahim Alameddine, J. David Allan, David B. Baker, Nathan S. Bosch, Remegio Confesor, Joseph V. DePinto, David M. Dolan, Jeffrey M. Reutter, and Donald Scavia, 2012. Discussion –“Nutrient Inputs to the Laurentian Great Lakes by Source and Watershed Estimated Using SPARROW Watershed Models” by Dale M. Robertson and David A. Saad. Journal of the American Water Resources Association (JAWRA) 1-10. DOI: 10.1111/jawr.12006

Abstract:  Results from the Upper Midwest Major River Basin (MRB3) SPARROW model and underlying Fluxmaster load estimates were compared with detailed data available in the Lake Erie and Ohio River watersheds. Fluxmaster and SPARROW estimates of tributary loads tend to be biased low for total phosphorus and high for total nitrogen. These and other limitations of the application led to an overestimation of the relative contribution of point sources vs. nonpoint sources of phosphorus to eutrophication conditions in Lake Erie, when compared with direct estimates for data-rich Ohio tributaries. These limitations include the use of a decade-old reference point (2002), lack of modeling of dissolved phosphorus, lack of inclusion of inputs from the Canadian Lake Erie watersheds and from Lake Huron, and the choice to summarize results for the entire United States Lake Erie watershed, as opposed to the key Western and Central Basin watersheds that drive Lake Erie’s eutrophication processes. Although the MRB3 SPARROW model helps to meet a critical need by modeling unmonitored watersheds and ranking rivers by their estimated relative contributions, we recommend caution in use of the MRB3 SPARRROW model for Lake Erie management, and argue that the management of agricultural nonpoint sources should continue to be the primary focus for the Western and Central Basins of Lake Erie.

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