Dam safety and water management during unusual and extreme hydrologic events

The Southwestern Division of the Army Corps of Engineers takes in all or part of Arkansas, Kansas, Missouri, Oklahoma, and Texas. Climate can be highly variable and unpredictable in this region of the country. In recent years a particularly wide range of hydrologic events has been ongoing. Most of the region was in a very severe drought from early 2004 through late 2006, resulting in many of the multipurpose flood control lakes being drawn down to near record low pools. This climactic trend then reversed, and by the summer of 2007 extreme flooding was occurring over a large portion of Texas, Oklahoma, and Kansas. In March and April 2008, record flooding was occurring in Arkansas. The White River system of multipurpose lakes was hit especially hard with record pools set at four of the five lakes. The challenges of excessive rainfall immediately following a prolonged period of drought can test whether existing water management plans are adequate to handle broad ranges of climactic conditions. This paper will explore the water management challenges faced by the 2008 flooding, how hydropower releases were used to increase total outflow to prevent overtopping and how existing water control plans effectively served to manage the extreme conditions while maintaining public safety and minimizing downstream losses. (author)