Lake Merced is in dire need of raising its water levels, according to the San Francisco Public Utilities Commission.
By raising the water level, the SFPUC said the integrity of the lake’s biodiversity, recreational activities and emergency usability would greatly improve.
The reason for Lake Merced’s drop in water level can be attributed to irrigation for facilities like the Lake Merced Golf Course and nearly two decades of drought. Lower lake levels have a negative effect, specifically on vegetation and aquatic life, according to the SFPUC.
To combat the damage, the SFPUC will refill the lake with a combination of storm and ground water. The Storm Water Diversion Project is one part of the master plan that has successfully raised the water levels two feet since 2004. At the Vista Grande Canal, a storm bowl collects water and redirects it through a canal—and purification process—into the lake.
Aside from using the canals as water purifiers, natural filters have recently been installed at the parking lot at Sunset and Lake Merced Boulevards. Before this, storm water laced with dirt and oil would pass directly from the parking lot into the lake. Now, it must go through a purification process. The water goes into catch basins and then travel through a series of “bioswales,” planted areas that act as natural filters.
“With a reduction in water level, certain species of fish are threatened,” said Suzanne Gautier, 53, communications director for the SFPUC. “Trout, for example, live in cooler water, which is normally found at the bottom of a deep lake.”
Gautier said the water must be refilled incrementally to allow vegetation and nesting birds time to adjust to the change.
“I don’t know if we’ll ever be ‘finished,’” Gautier said. “We want to make a long-term, sustainable program.”
The optimum lake level they are working to achieve is 25-27 feet.
Amy Golub, a 21-year-old environmental studies major at SF State, said that keeping Lake Merced’s levels up to par isn’t just a matter of preserving for the sake of preservation.
“Conservation is used to preserve for economic reasons,” Golub said. “With Lake Merced you have boating, fishing, a lot of recreational usage. The National Park and Rec is in charge of these, and so raising the lake levels is beneficial for them.”
Since she has studied at SF State, Golub has lived at the Villas at Park Merced and observed firsthand what kind of natural biology exists.
“Lake Merced is a naturally formed lake,” she said. “But I have a feeling that most of the species there aren’t endemic. The fish were brought in for fishing reasons.”
The Lake Merced Water Level Restoration Program is headed by a steering committee of various local organizations, including Erik Rosegard, associate professor of recreation and leisure studies at SF State.
“Our biggest concern is not to raise the water levels too high,” Rosegard said. “Because the droughts have been going on for 20 plus years, a whole new ecosystem was created, and flooding the lake too high would be detrimental.”
Lake Merced is one of two coastal freshwater lakes in California, and has served as a source of water for fire fighting and non-drinking emergency use in San Francisco.