Decommissioning of NRCS Flood Control Dams in Oklahoma

More than 11,000 dams have been constructed nationwide in the last 62 years by the Natural Resources Conservation Service and their local project sponsors. With this many dams in service, it is inevitable that many will require repair or rehabilitation due to physical deterioration or changes in hazard classification. It is also certain that the costs required in bringing some of these dams into compliance with current safety criteria would be so great that the only economically viable option is decommissioning.
Dam decommissioning primarily involves the physical removal of the embankment and associated works in a manner that leaves the landscape in a condition as close to its natural state as practical. As easy as this may sound, the environmental, social, and possible economic impacts of the removal are complicated. Some of these dams have been in place for more than 60 years. Upstream and downstream channels have adapted to their presence over this period and have usually reached equilibrium. Removal of the dam may result in the physical impacts of increased downstream flooding, release of sediment with possible toxins or excessive nutrients from the sediment pool, and stream channel or secondary erosion. There are also social impacts to consider, such as the loss of recreational use, agricultural water and wildlife benefits. This paper looks at three flood control dams in Oklahoma that have been, or are in the process of being decommissioned. It focuses on practical planning, design, and construction considerations for dam removal that help to mitigate all of the impacts of decommissioning. 18 pp. 5 references.