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Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

Authors

  • Richard A. Rebich,

    1. Respectively, Supervisory Hydrologist (Rebich), U.S. Geological Survey, Mississippi Water Science Center, 308 S. Airport Rd., Jackson, Mississippi 39208
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  • Natalie A. Houston,

    1. Hydrologist, Geographer (GIS), Hydrologist, Biologist (Houston, Pearson, Ging, Hornig), U.S. Geological Survey, Texas Water Science Center, Austin, Texas 78754
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  • Scott V. Mize,

    1. Hydrologist (Mize), U.S. Geological Survey, Louisiana Water Science Center, Baton Rouge, Louisiana 70816
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  • Daniel K. Pearson,

    1. Hydrologist, Geographer (GIS), Hydrologist, Biologist (Houston, Pearson, Ging, Hornig), U.S. Geological Survey, Texas Water Science Center, Austin, Texas 78754
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  • Patricia B. Ging,

    1. Hydrologist, Geographer (GIS), Hydrologist, Biologist (Houston, Pearson, Ging, Hornig), U.S. Geological Survey, Texas Water Science Center, Austin, Texas 78754
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  • C. Evan Hornig

    1. Hydrologist, Geographer (GIS), Hydrologist, Biologist (Houston, Pearson, Ging, Hornig), U.S. Geological Survey, Texas Water Science Center, Austin, Texas 78754
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  • Paper No. JAWRA-10-0179-P of the Journal of the American Water Resources Association (JAWRA). Discussions are open until six months from print publication.

  • Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#OnlineOpen_Terms

(E-Mail/Rebich: rarebich@usgs.gov).

Abstract

Rebich, Richard A., Natalie A. Houston, Scott V. Mize, Daniel K. Pearson, Patricia B. Ging, and C. Evan Hornig, 2011. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico From Streams in the South-Central United States. Journal of the American Water Resources Association (JAWRA) 47(5):1061-1086. DOI: 10.1111/j.1752-1688.2011.00583.x

Abstract:  SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%).

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