Water Quality Monitoring and Research at Lake Wateree, SC

Abstract

For at least two decades the water quality in Lake Wateree has been the focus of much attention by state and local governments, lake property owners, Duke Energy, and the University of South Carolina (USC). Several locations on or near the lake are on the state 303(d) list for excess nutrients or the consequences of excess nutrients. Most nutrient loading is from sources upstream in the Catawba River watershed. From 1999‐2003 the all‐volunteer Lake Wateree Water Watch (WW) group conducted monthly sampling for field parameters at 19 locations in the lake. The monitoring effort resumed in 2008 with assistance from faculty, students, and staff at the University of South Carolina. This presentation will provide an overview of the sampling effort and its results. In late 2011 a study was completed that compared sampling data from the 1999‐2003 interval to data from 2008‐2011. There was some improvement in water clarity between the two intervals. This appears to have resulted in an increase in phytoplankton production as indicated by increased pH at some locations. Concurrent with the monitoring a research project was conducted during summer 2011. The purpose was to measure fluxes of nutrients (phosphorus and nitrogen) between lake sediment and the overlying water, measure concentrations of nutrients in the sediments, and measure nutrients and field parameters vertically throughout the year. The conceptual justification for the work was based on two prior studies. In 1996 a water quality simulation model of the lake suggested nutrient fluxes may be occurring. Then during summer 2009 special reconnaissance sampling showed the physical conditions develop under which nutrient fluxes could occur. Our findings indicate the exchange of nutrients between the sediment and overlying water occurs in both directions. The direction at any given time depends on other physicochemical characteristics of the lake that are probably related to season and riverine inflow. INTRODUCTION In 1996 the (Lake) Wateree Home Owners Association (WHOA) contracted with the University of South Carolina to conduct a study to assess lake water quality, the then-current monitoring strategies, and to recommend future monitoring needs. One of the main tasks of the study was development of a water quality simulation model of eutrophication kinetics in the lake (Tufford et al. 1999). Among the recommendations from that study were that WHOA initiate a volunteer monitoring program that would incorporate both spatial and temporal scale considerations to ensure a more holistic understanding of water quality in the lake and that short-term intensive studies should be conducted to gain insight into specific physical and biochemical processes (Tufford et al. 1997). In 1999 WHOA, through its affiliated Water Watch group, initiated sampling of water quality field parameters at nineteen locations in the lake. This effort continued into 2003. The work was restarted in 2008, this time in partnership with researchers at the University of South Carolina (USC), and continues today. There are currently two lake groups: WHOA on the Fairfield County side of the lake and the Lake Wateree Association (LWA) on the Kershaw County side. Concurrent with the monthly monitoring several special projects were initiated, including studies of: a small tributary watershed looking at potential sources of sediment that caused elevated turbidity in the embayment, dissolved oxygen conditions at the sediment/water interface during summer, the flux of nutrients across the sediment/water interface, and details of summer chlorophyll and dissolved inorganic nutrients in two tributary embayments. This paper provides details of the routine monthly sampling and a comparison of results from the two sampling efforts, 1999-2003 versus 2008-present. We also present and discuss results from the two studies of the sediment/water interface and provide brief summaries of other projects. We conclude with a discussion of the benefits and challenges facing a viable volunteer monitoring effort.