AWWA ACE54355

A lake monitoring program was conducted at Black Shoals reservoir in Rockdale County, Georgia, to collect, analyze, and evaluate lake water quality data between the spring and fall turnover events to identify source(s) of problematic constituents such as iron and manganese. The primary goal of the monitoring program was to characterize the water quality of the water supply impoundment for design of in-lake aeration facilities that are being proposed as part of the Rockdale Water Resources (RWR) Water Treatment Plant (WTP), Rockdale County, Georgia. In particular, the lake monitoring program was designed to assess the spatial and temporal water quality in the lake, which are necessary for the sizing and siting of in-lake aeration facilities. In addition, the monitoring program will provide valuable data to determine the optimal depth of outflow releases to minimize treatment requirements at the WTP and downstream environmental impacts. Lake monitoring took place from February through September, 2000. Three sample points were established in the lake. These sampling points were selected to give both a vertical and longitudinal profile of the reservoir along its primary flow axis. Temperature and dissolved oxygen weredetermined in the field at 1-foot depth intervals to better define thermal stratification. Sampling for other parameters was conducted at 5-foot depth intervals. Samples were analyzed for the following parameters: alkalinity; turbidity; chlorine demand; total iron; total manganese; sulfide; ammonia; nitrate; and total phosphorus. This paper summarizes the lake monitoring data analysis. In addition, an analysis of lake aeration requirements is presented, along with a discussion of proposed lake aeration facilities and anticipated benefits from lake aeration on water treatment costs and lake water quality. Includes tables, figures.