The Karst Pages

INTRODUCTION TO KARST ENVIRONMENTAL PROBLEMS Sinkhole Flooding

Ponding of storm water runoff in sinkholes is a part of the natural hydrologic system in karst regions. Ponding occurs during periods of intense rainfall when: 1) the rate of storm water runoff exceeds sinkhole drainage capacities, 2) the capacity of the cave system to transmit storm water is exceeded and water must be stored temporarily in sinkholes, and 3) there is a backwater effect on groundwater flow from sinkholes with bottoms lower than the level of surface streams at flood stage.  Particularly in urban areas, structures are often built within sinkhole flood plains. Flooding problems may be greatly aggravated by:

Increased rates of runoff caused by land use changes, especially from impervious roofed or paved areas. Decreased storage due to sinkhole grading and filling. Clogging of sinkhole drains by debris and silt.

In an attempt to reduce sinkhole flooding, sinkhole drains are sometimes unclogged. Also, storm water runoff may be routed into drainage wells drilled into the aquifer. One of the most effective solutions to the problem of sinkhole flooding is the establishment of sinkhole flood plain easements.

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