Application of a steady-state nutrient model and inferences for load reduction strategy in two public water supply reservoirs in eastern Connecticut

Abstract Mansfield Hollow Lake (MHL) and Willimantic Reservoir (WR) are two reservoir lakes located in eastern Connecticut in the northeastern United States. MHL formed behind the Mansfield Hollow Dam constructed by the U.S. Army Corps of Engineers in 1952 and is primarily fed by the Fenton, Mount Hope and Natchaug Rivers. The WR lies approximately 1-km downstream from the Mansfield Hollow Dam. Total dissolved nitrogen, phosphorus and chlorophyll a measurements indicate the water bodies could be classified as borderline mesotrophic/eutrophic. A steady-state numerical software package (Bathtub) designed to facilitate application of empirical eutrophication models to morphometrically complex reservoirs was used to determine the trophic status in MHL and WR based on different phosphorus and nitrogen loading budgets. The short hydraulic residence times and rapid flushing rates in MHL and WR are directly related to the flow rates in the streams discharging into MHL. The low flow period could significantly incr...