Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States
Water-Resources Investigations Report
94-4001
By: Larry J. Puckett
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Abstract
Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land use, population, and physiography. Fertilizer sources of nitrogen are proportionally greater in agricultural areas of the West and the Midwest than in other parts of the Nation. Animal manure contributes large proportions of nitrogen in the South and parts of the Northeast. Atmospheric deposition of nitrogen is generally greatest in areas of greatest precipitation, such as the Northeast. Point sources (sewage and industrial) generally are predominant in watersheds near cities, where they may account for large proportions of the nitrogen in streams. The transport of nitrogen in streams increases as amounts of precipitation and runoff increase and is greatest in the Northeastern United States. Because no single nonpoint nitrogen source is dominant everywhere, approaches to control nitrogen must vary throughout the Nation. Watershed-based approaches to understanding nonpoint and point sources of contamination, as used by the National Water-Quality Assessment Program, will aid water-quality and environmental managers to devise methods to reduce nitrogen pollution.
Suggested Citation
Puckett, L., 1994, Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States (Revised Mar 1994): U.S. Geological Survey Water-Resources Investigations Report 94-4001, iii, 9 p., https://doi.org/10.3133/wri944001.
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States |
| Series title | Water-Resources Investigations Report |
| Series number | 94-4001 |
| DOI | 10.3133/wri944001 |
| Edition | Revised Mar 1994 |
| Year Published | 1994 |
| Language | ENGLISH |
| Publisher | Geological Survey (U.S.) |
| Contributing office(s) | National Water Quality Assessment Program |
| Description | iii, 9 p. |