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Created by U.S. Geological Survey and integrated into the Land Transformation model (developed by Dr. Bryan Pijanowski at Purdue University)


The SPARROW (SPAtially Referenced Regression On Watershed attributes) is a nutrient load model that relates Phosphorus (P) loads to six significant sources on the landscape: point sources, urban land uses, manure from confined and unconfined animals, farm fertilizers, and forested land uses. The model considers landscape factors (climate, soils, topography, etc.) and transport and fate properties (stream network, loss, etc.) at the stream segment catchment level to estimate mean-annual load delivered to the stream. Catchment loads are then aggregated to estimate P load at the HUC 8 spatial scale. Running the Land Transformation Model alongside SPARROW allows the model to estimate P loads in the future based on projected future land use scenarios.


  • Estimate current and future nutrient loads in your HUC 8 watershed based on two future land use scenarios: 1) Rapid Urban Expansion or 2) Biofuels Expansion
  • View percent contribution of Phosphorus load from 6 major sources
  • Save and print maps and data for planning and decision making

Additional Information


  1. Labeau, M. B., Robertson, D. M., Mayer, A. S., Pijanowski, B. C., & Saad, D. A. (2014). Effects of future urban and biofuel crop expansions on the riverine export of phosphorus to the Laurentian Great Lakes. Ecological Modelling, 277, 27-37. doi:10.1016/j.ecolmodel.2014.01.016
  2. Robertson, D. M., & Saad, D. A. (2011). Nutrient inputs to the Laurentian Great Lakes by source and watershed estimated using SPARROW watershed models. Journal of the American Water Resources Association, 47(5), 1011-1033. doi:10.1111/j.1752-1688.2011.00574.x
  3. Schwarz, G.E., Hoos A. B., Alexander, R. B., Smith, & R. A. (2006). The SPARROW surface water-quality model: theory, application, and user documentation. U.S. Geological Survey Techniques and Methods Report. Book 6. Chapter B3. U.S. Geological Survey, Reston, VA.

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