Nonpoint source pollution in the Mosquito Creek watershed /

Abstract

The Mosquito Creek watershed is an important water resource in Trumbull County. Mosquito Creek Reservoir has served as a source of municipal water supply for the City of Warren since 1954; the reservoir is also used extensively for recreation. The purpose of this study was to estimate major nonpoint source (NPS) pollutant loadings to the streams within the Mosquito Creek watershed by stream monitoring and computer modeling, and to identify potential locations for pollutant loading reduction. Monitoring stations were established on Mosquito Creek and all major tributaries. The parameters monitored included flow, pH, turbidity, suspended solids, solub1e reactive phosphorus, total phosphorus (TP), ammonia nitrogen, and nitrate nitrogen. Total pollutant loads of 92,410 lb/yr for TP, 33,040 lb/yr for nitrate nitrogen, 48,540 lb/yr for ammonia nitrogen and 15,200 t/yr for suspended solids were obtained from the monitoring data. The computer model, STEPL, estimated the total loads as: 211,890 lb/yr for total nitrogen (N), 55,290 lb/yr for TP, 558,350 lb/yr for BOD and 9,040 t/yr for sediments (i.e. suspended solids). Loading estimates based on monitoring were significantly higher than those based on STEPL. Based on monitoring results, the export rates of TP, N, and SS are highest in the northern and western parts of Mosquito Creek watershed, and lower in the southern and eastern parts. Cropland, urban land and septic systems were predicted by STEPL to be the major sources of NPS pollution in the Mosquito Creek Reservoir watershed.