As neighborhoods in West Lake Hills have been built out, stormwater that used to not be an issue has begun impacting downhill properties and overwhelming city infrastructure, according to City Administrator Robert Wood.

“New homes and home additions in West Lake Hills are being built larger than ever before,” Wood said. “With larger houses comes more impervious cover such as sidewalks, porches and driveways [where water runs off].”

After successive floods in 2015 city leaders decided to create a drainage manual to guide staff in fixing and preventing further issues. Phase 1 was a comprehensive report of prioritized improvement projects, which was completed in 2017.

“The second part of the discussion was what regulations needed to be in place when people build a house or make a significant change on private property,” Wood said. “It’s about what we needed to have people do so we can relieve drainage issues.”

The city worked on the new design manual for a year and a half before it was approved by City Council on March 28.

Before the design manual was created drainage requirements were written only in the city code. The information was outdated and spread throughout various sections of the code, making it hard for people wanting to do a project to find, according to Wood.

The city decided the best solution was to put together a drainage design manual—one document containing all of the requirements—and remove the old information from the code. The drainage manual is posted online.