Storm and Hurricane Disturbances on Phosphorus Storage within an In-Stream Wetland.

The ability of wetlands to hold phosphorus (P) makes them and important landscape feature that help to protect water quality. However, their ability to retain P can be affected through hydrologic disturbances caused by both storms and flooding. An animal waste impacted in-stream wetland (ISW) located at the Herrings Marsh Run watershed, Duplin Co., NC, was studied for four years (1996-1999) to evaluate the effects of storms and hurricanes on P storage pools. Outflow dissolved P concentrations and mass export loads were used to measure the storm effect on P release from the ISW. Although not all storm events caused significant amounts of dissolved P release from the ISW, multiple storms in close succession significantly increased DP export. Major changes in DP along with sediment total P concentrations within the ISW occurred as a result of intense storm activities during the four years of this study. Dissolved P concentrations in sediment pore water and sediment total P concentrations decreased within the ISW suggesting that the effects of extreme events, such intense storms and hurricanes in close succession may affect the long term water quality functions of in-stream wetlands.