White pelicans sit above water level at Mitchell Lake.
White pelicans sit above water level at Mitchell Lake. Credit: Bonnie Arbittier / San Antonio Report

The U.S. Army Corps of Engineers has allocated $1.5 million for a pilot project to determine whether manmade wetlands can help filter pollution leaving San Antonio’s Mitchell Lake.

To combat algae that’s lowering dissolved oxygen levels in the water flowing downstream from the shallow lake on the South Side, the San Antonio Water System is planning to install water-filtering wetland plants and make changes to a dam that will allow the utility to better control water levels.

SAWS owns the roughly 600-acre former sewage dump that in recent times has been transformed into a bird sanctuary known as Mitchell Lake Audubon Center.

U.S. Rep. Will Hurd (R-Helotes), who toured Mitchell Lake in February, and U.S. Rep. Henry Cuellar (D-San Antonio) announced the funding on Friday. Both worked to secure funding from the Corps in its 2018 fiscal year.

“The hundreds of bird and plant species thriving on site have proven to provide impressive economic, environmental and health benefits to the surrounding community,” Hurd said in a prepared statement.

SAWS’ board of trustees in October approved a $1.3 million contract for designing, managing construction, and operating the project. The utility also paid $4 million for 283 acres south of the lake.

If completed as proposed, the manmade wetlands could eventually cover 125 acres.

Brendan Gibbons

Brendan Gibbons is the San Antonio Report's environment and energy reporter.