SPARROW National Nutrient Results

SPARROW Surface Water-Quality Modeling
Estimated Nitrogen Export from Watersheds of the Conterminous United States

Map modified from:

Smith, R.A., G.E. Schwarz, and R.B. Alexander, 1997, Regional interpretation of water-quality monitoring data, Water Resources Research, v. 33, no. 12, pp. 2781-2798

The map displays SPARROW estimates of total nitrogen export (i.e., yield expressed in units of kilograms per square kilometer per year) for hydrologic cataloging unit watersheds in the conterminous United States. The estimates quantify nitrogen contributions from local (within-hydrologic unit) sources, exclusive of inflows from upstream watersheds.

For additional information, see the SPARROW application on estimating nutrients in streams of the conterminous United States.

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Last modified: Tue Apr 21 11:02:40 EDT 1998