Estimates of diffuse phosphorus sources in surface waters of the United States using a spatially referenced watershed model

• DOI: 10.2166/wst.2004.0150
• Publication Date: 2018-05-18T13:04:38Z
• Authors: R.B. Alexander; R.A. Smith; G.E. Schwarz
• Keywords: Soil; 13. Climate action; Calibration; Geographic Information Systems; Water Movements; Agriculture; Phosphorus; Water Pollutants; Models, Theoretical; 15. Life on land; United States; 6. Clean water; Environmental Monitoring

The statistical watershed model SPARROW (SPAtially Referenced Regression On Watershed attributes) was used to estimate the sources and transport of total phosphorus (TP) in surface waters United States. We calibrated using stream measurements TP from 336 watersheds mixed land use spatial data on topography, soils, hydrography, (agriculture, forest, shrub/grass, urban). explained 87% variability log transformed flux (kg yr(-1)). Predictions yield ha(-1) yr(-1)) were typically within 45% observed values at monitoring sites. identified appreciable effects streams, reservoirs transport. estimated aquatic rates removal declined with increasing size water flushing (i.e. areal hydraulic loads). A budget for 2.9 million km2 Mississippi River Basin provides a detailed accounting delivery waters, export major interior associated each land-use type.