Ecosystem restoration - Water quality changes from riparian buffer restoration in Connecticut

One-half of a 35- by 250-m riparian buffer cropped in corn (Zea mays L.) wa s seeded with fine leaf fescue (Festuca spp.) and allowed to remain idle to determine water quality changes resulting from riparian buffer restoration . A corn control was also used in this paired watershed design located in C onnecticut. Water, N, and P fluxes were determined for precipitation, overl and now, and ground water. Also, an N mass balance was calculated. Total Kj eldahl nitrogen (TKN) and total phosphorus (TP) concentrations significantl y (P < 0.05) increased as ground water flowed through the restored buffer. Nitrate N (NO3-N) concentrations declined significantly but most (52%) of t he decrease occurred within a 2.5-m wetland adjacent to the stream. An N ma ss balance for the 2.5-m strip indicated that denitrification only accounte d for 1% of the N losses and plant uptake was from 7 to 13% of the N losses annually. Ground water was the dominant source of N to the buffer and also the dominant loss. Restoration of the riparian buffer decreased (p < 0.05) overland flow concentrations of TKN by 70%, NO3-N by 83%, TP by 73%, and t otal suspended solids (TSS) by 92% as compared with the control. Restoratio n reduced (p < 0.05) NO3-N concentrations in ground water by 35% as compare d with the control. Underestimated denitrification and dilution by upwellin g ground water in the wetland area adjacent to the stream were believed to be primarily responsible for the decreasing NO3-N concentrations observed.