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Lewisville Dam Upgrades Under Construction

Flood protection upgrades on the structure are expected to be complete in 2026
Courtesy of Lake Lewisville

Following 2015's record-high lake levels, flood protection upgrades to the Lewisville Dam are now underway. As originally reported by NBCDFW, flood protection upgrades on the 71-year-old structure have begun. 

In 2015, the site began to draw concern after record-high lake levels caused massive flow over the spillway, causing nearby, normally dry areas to flood. Seepage also increased after the 2015 breach, leaving one seepage area constantly muddy. All of this led to the upgrading project. 

Officials toured the site with Stacy Gray, dam program manager on May 25 to see the progress of the work. 

“We put in a system that would safely collect all of that seepage, get rid of that muddiness and allow us to see what was happening when it was happening,” Gray said. “Seepage is a normal occurrence in an earthen dam... This is just our way to monitor it and make sure it is performing as we want it to.”

Construction crews are currently drilling anchors 180 feet into the ground to secure the spillway, as well as upgrading seepage collection areas with new monitoring equipment. This equipment will ensure water coming from underneath the dam is not causing any damage. 

Lake Lewisville sits between the Trinity River levees and feeds into the Dallas Floodway. It is estimated that 431,000 people and $24 billion worth of property lie in the flood path of Lake Lewisville. 

“So even though it’s never happened, we want to make sure as responsible dam owners that we’re doing our part to minimize the risk,” Gray said.

Currently, the lake sits at 522 feet and the current spillway top is 532 feet. 

The flood protection upgrades are estimated to cost $150 million and are federally funded through the U.S. Army Corps of Engineers. 

The upgrades are expected to be completed in 2026.