Lake Seminole Hydrologic Analysis - USGS

Project Chief:Lynn Torak
Cooperator: Georgia Department of Natural Resources, Environmental Protection Division
Year started: 1999

THIS PROJECT HAS BEEN COMPLETED AND IS BEING ARCHIVED IN ITS FINAL CONFIGURATION

Problem

Multiple uses of freshwater supplies in the lower Apalachicola-Chattahoochee-Flint (ACF) River Basin have been the concern of water managers in the States of Alabama, Florida, and Georgia for many years. Numerous studies have been conducted in an attempt to understand the complex relations that exist between hydrologic-system components and natural stresses, and to answer questions regarding the effects on those relations caused by human intervention. Although previous studies addressed important water-resource issues in the lower ACF River Basin, by design, none provided a mechanism for collecting real-time hydrologic data necessary to develop and maintain an accurate water budget for Lake Seminole and the stream-lakeaquifer flow system. None of these studies focused on investigating the hydrologic and hydrogeologic implications of impoundment of Lake Seminole by construction of Jim Woodruff Lock and Dam and the effect of the lake on other components of the flow system. In response to these needs, the U.S. Geological Survey (USGS) has entered into a cooperative agreement with the Georgia Department of Natural Resources to develop a water budget of the Lake Seminole area, to reasonably estimate the volume of water flowing into Florida before and after construction of the dam, and to monitor the effects of any sinkhole collapse beneath the lake.

Objectives

• Develop a water budget for Lake Seminole that will result in reasonable understanding of the effect of the lake on the overall flow system in the lower ACF River Basin;
• Compare current (2001) and pre-Lake Seminole ground-water and surface-water flow to determine whether the volume of water flowing out of Georgia has changed significantly after construction of Jim Woodruff Lock and Dam and filling of the lake;
• Evaluate the possibility of a substantial amount of water entering the ground-water system from Lake Seminole, flowing beneath Jim Woodruff Lock and Dam, and entering Florida downstream of the dam; and
• Assess the likelihood of failure of dissolution features in the karst limestone of the lake bottom, such as sinkhole collapse, and the likelihood of sudden partial or complete draining of the lake. If these events are likely, then propose a data-collection system to monitor conditions that might lead to sudden draining of Lake Seminole.