Report: Lake needs to raise water levels 

Artificial wetlands will be built along John Muir Drive and groundwater will be pumped into Lake Merced in a bid to replenish the lake’s water levels if new recommendations by a city task force are implemented.

A Public Utilities Commission-led task force in a new report recommends spending $16 million to raise water levels by an additional 2 to 3 feet over current levels based on meetings with dozens of environmental and recreational groups and community members in recent years.

The 300-acre lake is part of a collection of four ocean-front lakes that together create a 600-acre ecological sanctuary popular with boaters, fishers, hunters, bird-watchers and other nature lovers and is located just south of the zoo.

In the 1980s and 1990s, lake levels dropped 10 feet because of adrought, mostly because storm water was increasingly diverted away from the lake, according to the report. Increasing amounts of local and regional groundwater was also pumped for irrigation.

Falling water levels impact people, fish, turtles, snakes, frogs, 48 species of birds and other wildlife that use the lake, according to the report.

The lake, owned by the Public Utilities Commission, provided drinking water for Bay Area cities until the 1930s and is still designated as an emergency water source, according to a city report. It has been managed by the Recreation and Park Department since 1950.

The report also recommends pumping nearby groundwater directly into the lake and building 5.2 acres of heavily vegetated wetlands along John Muir Drive. PUC program manager David Behar recently told commissioners the wetland "will take storm water from Daly City, treat it, remove some of the contaminants, and put that water into Lake Merced."

Wetlands can trap and clean storm water runoff through natural biological processes. The report rejected a proposal to pump water into Lake Merced from Hetch Hetchy Dam in Yosemite National Park — a recommendation welcomed by a task force member from fishery conservation group California Trout.

"The solution which is recommended," Mondy Lariz told commissioners, "is in my viewthe best environmental solution — it avoids using Hetch Hetchy water."

A review of the environmental impact of the proposed project is expected to begin soon.

Proposed wetlands along John Muir

» Located at western shore of South Lake between Vista Grande Canal and John Muir Drive

» Would help restore lake water-levels and reduce flooding at John Daly Boulevard

» Would provide 5.2 acres of wildlife habitat

Source: SFPUC

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Sunday, Mar 18, 2018


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