ROLE OF WETLANDS IN REDUCING PHOSPHORUS LOADING TO SURFACE-WATER IN 8WATERSHEDS IN THE LAKE CHAMPLAIN BASIN

A landscape-level approach was applied to eight rural watersheds to as sess the role that wetlands play in reducing phosphorus loading to sur face waters in the Lake Champlain Basin. Variables summarizing various characteristics of wetlands within a watershed were calculated using a geographic information system and then compared to measured phosphor us loading through multiple regression analyses. The inclusion of a va riable based on the area of riparian wetlands located along low- and m edium-order streams in conjunction with the area of agricultural and n onwetland forested lands explained 88% of the variance in phosphorus l oading to surface waters. The best fit model coefficients (P-load = 0. 86Ag + 0.64For - 30Ripwet + 160) suggest that a hectare of riparian we tland may be many times more important in reducing phosphorus than an agricultural hectare is in producing phosphorus. These results provide additional support for the concept that protection of riparian wetlan ds is an important management strategy for controlling stream water qu ality in multiuse landscapes.