Submitted to: American Water Works Association Annual Conference and Exposition
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 2004
Publication Date: June 28, 2004
Citation: Novak, J.M., Stone, K.C., Hunt, P.G., Szogi, A.A., Watts, D.W., Johnson, M.H. 2004. Dissolved phosphorus retention and release characteristics of riparian zones and in-stream wetlands [abstract]. American Water Research Association Conference, June 28-30, 2004, Lake Tahoe, California. 2004 CDROM. Technical Abstract: In some southeastern Coastal Plain watersheds, some soils have phosphorus (P) concentrations that exceed crop nutrient needs because they have had manure from intensive animal production applied to them over a long period of time. These soils have a low ability to sorb P because they are sandy and extremely weathered. Consequently, P can be easily desorbed by water and transported via runoff, erosion of P-laden sediments, and leaching to streams and river systems. Phosphorus transport into nutrient-sensitive coastal estuaries and bays can accelerate eutrophication and create water quality concerns in these ecologically and economically important water bodies. Off-site P transport was reduced through management practices that utilize grass and forested riparian zones capable of retaining P and buffering its entry into a local stream. The riparian zones were shown to be effective at reducing both surface and subsurface P movement from a North Carolina Coastal Plain spray field that had received 10 years of intensive swine manure application rates. Other reductions in dissolve phosphorus (DP) concentrations occur as streams flow through in-stream wetlands. The wetlands provided effective short-term P retention as shown by examination of DP in the inflow and outflow, although disturbances of the water can alter sediment P equilibria increasing P releases. Careful management strategies that reduce P equilibria shifts within these wetlands are necessary to insure effective long-term P retention.