Paper No. 96042 of the Journal of the American Water Resources Association (former Water Resources Bulletin). Discussions are open until December 1, 1997.
NONPOINT SOURCE DISCHARGES OF NUTRIENTS FROM PIEDMONT WATERSHEDS OF CHESAPEAKE BAY1
Article first published online: 8 JUN 2007
JAWRA Journal of the American Water Resources Association
Volume 33, Issue 3, pages 631–645, June 1997
How to Cite
Jordan, T. E., Correll, D. L. and Weller, D. E. (1997), NONPOINT SOURCE DISCHARGES OF NUTRIENTS FROM PIEDMONT WATERSHEDS OF CHESAPEAKE BAY. JAWRA Journal of the American Water Resources Association, 33: 631–645. doi: 10.1111/j.1752-1688.1997.tb03538.x
- Issue published online: 8 JUN 2007
- Article first published online: 8 JUN 2007
- nonpoint source pollution;
- water quality;
- Chesapeake Bay
ABSTRACT: We measured annual discharges of water, sediments, and nutrients from 10 watersheds with differing proportions of agricultural lands in the Piedmont physiographic province of the Chesapeake Bay drainage. Flow-weighted mean concentrations of total N, nitrate, and dissolved silicate in watershed discharges were correlated with the proportion of cropland in the watershed. In contrast, concentrations of P species did not correlate with cropland. Organic P and C correlated with the concentration of suspended particles, which differed among watersheds. Thus, the ratio of N:P:Si in discharges differed greatly among watersheds, potentially affecting N, P or Si limitation of phytoplankton growth in the receiving waters. Simple regression models of N discharge versus the percentage of cropland suggest that croplands discharge 29–42 kg N ha-1 yr-1 and other lands discharge 1.2–5.8 kg N ha-1 yr-1. We estimated net anthropogenic input of N to croplands and other lands using county level data on agriculture and N deposition from the atmosphere. For most of the study watersheds, N discharge amounted to less than half of the net anthropogenic N.