September 2009 Meeting

Monday, September 14, 2009
6:00 - 7:30 pm

Pellissippi State Technical Community College
10915 Hardin Valley Road, Knoxville
J.L. Goins Administration Building, Cafeteria Annex


A Karst Hydrogeologic Investigation of the TNT Manufacturing Valley
at the Volunteer Army Ammunition Plant
Hamilton County, Tennessee

Frank R. Bogle
Tetra Tech Inc.
Oak Ridge, Tennessee

A karst hydrogeologic study was performed at the Volunteer Army Ammunition Plant in Hamilton County, Tennessee. Based on field observations, the facility did not appear to be constructed over a karst aquifer due to the scarcity of sinkholes, springs, and other karst features and the extreme thickness of the soils and residuum [10 to 135 feet thick (9 to 41 meters)]. However, numerous voids encountered during well installation indicate that a karst hydrogeologic study was needed. The study had five main objectives: 1) determine the degree of karst development, 2) establish the type and rate of groundwater flow, 3) determine the effectiveness of monitoring wells, 4) establish boundaries of the groundwater basins, and 5) determine if off-site springs receive groundwater from the site. The study included: 1) mapping the potentiometric surface of the uppermost aquifer, 2) performing a karst hydrogeologic survey using field reconnaissance and thermal infrared imaging for locating submerged springs in Chickamauga Lake, 3) determining aquifer flow characteristics to springs using water quality parameters, and 4) performing qualitative and quantitative dye traces to establish basin boundaries. A potentiometric map was constructed from water level measurements taken from monitoring wells at the site. Based on the map, the site is underlain by two groundwater basins&mdashone which drains north and the other which drains south. A records search and interviews with local residents who lived in the area before the impoundment of the lake indicated that there are several springs that are now submerged. A karst hydrogeologic inventory using field reconnaissance for surface springs and a thermal infrared survey for submerged springs located 23 springs, 16 of which were submerged in the lake. Analysis of water quality parameters collected from springs over a 17-week period indicated that the springs were primarily fed by conduit flow while dye traces established a groundwater flow rate that ranged between 296 feet per day (90 meters/day) to 2,294 feet per day (699 meters/day).


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