WHEN A LAKE'S INFLOW EQUALS ITS OUTFLOW, WHICH DIRECTION DO YOU DECIDE TO GO?: TO FILL OR NOT TO FILL AN EMPTIED LAKE

The altering of groundwater flow patterns in a karstic environment expedited the formation of large sinkholes in the southeastern end of Victory Lake causing it to drain immediately. Soon after the lake emptied in 1986, two unsuccessful attempts were made to restore the 32-acre lake. Some 22-years later, Victory Lake holds water seasonally, but would primarily be classified as a marshy wetland.

This research project monitored variables necessary to complete a water budget of Victory Lake to determine the potential for it to be restored fully or partially as a recreational focal point of Berry College campus. Weekly data collected over the past year include precipitation input, groundwater input, tributary inflow, evaporation, evapotranspiration, tributary outflow, and groundwater loss. Concurrently, the depth of the lake was measured along a transect of 12 stage gages.

About 50% of the total water-budget inflow consists of surface water; another 1.3% is added to the lake by precipitation. Our isotope analysis determined the lack of connectedness of groundwater and surface water; therefore groundwater input was not considered in the lake water-budget. The data complied for this water-budget outflow indicates a loss of 48% to surface water outflow and < 1% from evaporation and evapotranspiration. The amount of groundwater lost is inconclusive at this time.

Comparisons of monthly and seasonal water-budgets prove to be more significant in determining the drastic changes in volume at Victory Lake. We find that December through January surface water inflow is the dominant variable over precipitation in ratios similar to those stated above. However, April through July precipitation is the primary supplier of water to the system; the contribution of precipitation to the water budget from April through July ranges from 8 to 32%, whereas surface water inflow becomes negligible. During this same time frame, water is lost at variable rates through surface water outflow (3 to 82%) and evapotranspiration (8 to 84%).

From our analysis it is shown that the water budget of Victory Lake is not only driven by the volume of water supplied or lost, but also by the current shape of the basin, the location of the outflow culvert, beaver dams, sedimentation, and creeping marsh grasses. In conclusion, we suggest that reconstruction of Victory Lake is plausible with strategic planning.