ABSTRACT
During the winter and spring of 1994, the Knoxville, Tennessee area received significantly higher than normal rainfalls. Over fifteen percent of the city is underlain by sinkholes, and the severe rains caused several areas to flood. Flooding caused houses to be inundated, as well as roads, parts of the city zoo, and a large warehouse in an industrial park. To keep the flood waters at bay, large pumps ran almost continuously for over two months with little success. An investigation of the problem showed that sinkhole clogging is largely to blame, but in addition, the water table simply rose above some sinkhole bottoms. Dye tracing was used to help define the ground water basins and to determine if pumped water was being recirculated back into the flooded karst drainage system. At the warehouse, five storm water drain wells were subsequently drilled into caves and solution-enlarged fractures to divert runoff to the subsurface before entering the sinkhole bottom. In addition, several sinkholes were excavated to bedrock and perforated standpipes installed. Knoxville is presently drilling exploration holes to help drain some of its problem areas. Although catastrophic storm events may still flood the sinkholes, the frequency and severity of flooding hopefully will decrease.
