March 26, 2005

Despite Providing Important Wildlife Habitat, Lake Merced Remains Under-Funded and Over-Polluted

By Ryder W. Miller
Special to the Neighborhood Newswire

Lake Merced is “one of the most treasured remnants of San Francisco's original landscape," according to the San Francisco Recreation and Park Department. More than 50 species of birds seem to agree, breeding and nesting at the lake, including the threatened bank swallow, which nests at nearby Fort Funston and can be found at the lake in the spring. Other “special status” birds include the California black rail, salt marsh common yellow throat, and American peregrine falcon.

Native plants also abound on its banks. Jake Sigg, conservation chair for the local Yuerba Buena Chapter of California Native Plant Society, said one can find a host of unique species, including the San Francisco wallflower, yellow bush lupine, arroyo willow, seaside daisy, coyote bush, buckwheat, bee plant, sea pink, goldenrod, bush monkey flower, California sage brush, and others.

Shooting Range May Have Created Long-Term Environmental Hazards
In spite of its charms, the lake is marred by pollution, which could disrupt plans to increase water levels as a means to improve the health of the eco-system, and expand its recreational uses. Almost two decades ago 28 tons of lead shot were removed from the lake, a legacy of the Pacific Rod & Gun Club, which continues to operate in the area. However, in February the San Francisco Public Utilities Commission (SFPUC), which manages the lake, announced that lead and arsenic remain in shoreline soils.

Toxics chemicals in the soil could enter the lake’s water and potentially impact wildlife through biomagnification, by which internal concentrations of toxics are magnified up the food chain.

It‘s unclear what environmental risk, if any, these lingering contaminants pose. In 1995 the California Department of Fish and Game found that the risk of lead being absorbed by waterfowl was low. Dan Murphy, former president of the Golden Gate Chapter of the Audubon Society and a nearby resident, said birds which could be affected by lead poisoning include diving and ruddy ducks. But, he pointed-out, these species are also less likely to spend time at the lake because they may be frightened off by periodic shooting at the Rod and Gun Club.

Land birds which pick up grizzle -- hard materials which aid their digestion -- may ingest lead as part of their feeding practices, with possible adverse side affects. Hazardous chemicals in the soils could also potentially impact sediment-dwelling species, like clams and worms.

California Trout, which manages the fish at the lake, doesn’t believe the fish are likely to ingest harmful amounts of lead. "The risk of that happening is low," said Armondo Lariz, California Trout’s Lake Merced program manager. "We have to clean up what's there, and we have three years to do it," referring to current plans to raise water levels starting in 2007.

The pollution that potentially plagues local wildlife should give people pause as well. Historically, Lake Merced was a key city water source, and could serve as an emergency water reserve. But now the water must be treated before it’s drinkable, and fish caught there should be well-cooked to eliminate biological contagions, said Greg Bartow, Integrated Water Resources manager for the SFPUC. He added, "People should not be swimming there. Swimming is prohibited."

Linkage Between Lead and Rising Water Levels
A key question is what, if any, impact the lead discovery will have on plans to increase Lake Merced’s water levels. A larger and cleaner lake would create more recreational opportunities for boating and fishing, as well as provide an emergency water source for the city. "I would not characterize it as a snag," said Suzanne Gautier, SFPUC’s Citizen Involvement Coordinator, who expects that the problem is not serious enough to halt plans to raise the lake’s level. "It is a preliminary study. It hasn't been determined that a cleanup is necessary. It is information we need to consider as we look at all the impacts of raising the water level."

In its formal press release SFPUC stated that though there is no present risk from toxics at the Rod and Gun Club, "experts indicate that cleanup, capping, or soil treatment may potentially be warranted to allow lake levels to be raised safely."

Lake Plans Key Role in City’s Eco-System
Before sand deposits created a natural separation, Lake Merced was once attached to the sea. Spanish explorers Moncada and Palou named the lake “Laguna de Nuestra Senora de la Merced” -- Our Lady of Mercy - in 1775. Parts of Lake Merced and Fort Funston were granted to Jose Galindo, who created the Lake Merced Ranch: Rancho Laguna De La Merced. In the late 1800s, ranching gave way to recreational uses of the lake. Lake Merced became a pleasure ground where city residents could escape the urban environment.

In 1934, the establishment of Hetch Hetchy resulted in the discontinuation of Lake Merced as a city water source. But its status as an important recreational outlet and wildlife habitat has endured – as long as one doesn't look too closely beneath its reflective surface.

Help with restoration efforts at Lake Merced, including the creation of habitat for the endangered California quail at Harding Park: (415) 753-7265.