Work is under way, under a $6.4 million contract, to repair a 161-foot-long slide on the upstream face of the embankment of Lewisville Lake Dam (also called Lewisville Dam).
This work includes reconstructing the embankment and protecting it with stone riprap on the upstream side and Bermuda grass sod on the downstream side, the U.S. Army Corps of Engineers says.
The Corps detected safety issues at Lewisville Lake Dam on the Elm Fork of the Trinity River in Lewisville, Texas, in August during a routine screening. The rolled earthfill dam, which impounds 23,000-acre Lake Lewisville, is 6.2 miles long and provides conservation/water supply storage of 598,400 acre-feet.
The landslide occurred in June, and temporary measures involved covering it with tarps to protect it from rain.
The dam was identified as very high risk in 2005 because of confirmed and unconfirmed potential safety issues, as well as potential impacts of those issues on the large downstream populations that may be affected. The dam is located 22 miles northwest of Dallas. Additional studies of the dam were routinely scheduled as a result and in response to the risk.
In the meantime, interim risk reduction measures were implemented to reduce potential dam safety risks.
While Lewisville Lake Dam has some known dam safety issues, it is not at risk of failure, the Corps said in a press release.
The Lewisville Lake Dam Safety Assurance Project was listed among the top civil works projects for the Corps’ Southwestern Division for Fiscal Year 2013. The dam was considered to require “major maintenance.”