Effects of development on runoff and pollutant export.

Runoff from two similar drainage areas in the Piedmont physiographic region of North Carolina was monitored simultaneously for 5.6 years. One of the drainage areas was developed as part of a large residential subdivision, while the other remained in woods and agricultural fields. Runoff volume was 68% greater for the developed compared with the undeveloped area, and baseflow as a percentage of overall discharge was approximately 0% compared with 25% for the undeveloped area. Overall annual export of sediment was 95% greater for the developed area, while export of nitrogen and phosphorus forms was 66 to 88% greater for the developed area. These results document the significant increases in runoff, sediment, and nutrient export associated with residential development.