Turn Flood Basin Into Wetland, Environmental Group Asks

A Marina del Rey flood control basin, which once provided an unofficial home for discarded pets, should be converted to a wetland that could act as a natural filter for polluted runoff water before it flows into the ocean, an environmental group says.

The idea is being pushed by Heal the Bay, a Santa Monica-based environmental group, for the 10.7-acre Oxford Flood Control Basin between Washington Street and Admiralty Way at the northern end of the marina.

County officials say they like the idea, but are skeptical that it will work and are concerned about its potential effect on the basin’s primary function as a container for excess runoff water.

“We generally support the concept, but there are still a lot of unanswered questions,� said Eric Bourdon, assistant director of the county Department of Beaches and Harbors, which oversees the marina.

“We still have to determine who is going to fund it, because if it is going to cost a lot of money, we don’t have the funds,� Bourdon said.

More Study Needed

“We also have to determine if it is going to work scientifically, and we have to determine if it would be compatible and not hinder the primary function of the basin.�

Mark Gold, a Heal the Bay scientist, acknowledges that more data is needed to determine whether a wetland would work at the site. But he said that, if it does work, it could be the model for the conversion of other basins into wetlands.

Gold said that converting basins into wetlands could be as simple as planting vegetation such as eelgrass, cordgrass, pickleweed and saltgrass on the floor and sides of basins.

“This is an excellent opportunity for the county to lead in the implementation of runoff treatment technologies,� Gold said in a preliminary proposal to the county.

“If this wetland reduces the impact of runoff in Basin E of the marina, then perhaps other degraded wetlands can be used for the same purpose.�

Basin E receives the runoff water from the Oxford basin, and in a 1986 study was found to be the most polluted of the marina’s eight basins. The basins feed into a channel that flows out to the Pacific Ocean.

Gold said implementing his proposal could cost as little as $100,000 if volunteers could be found to plant the vegetation. He said he is waiting for soil and tide information from the county public works department before making another presentation to county officials.

$100,000 Price Tag

If a wetland cannot be created in the Oxford basin, Gold said he will try to put one in nearby Ballona Creek, which is overseen by the City of Los Angeles.

Gold said finding a way to treat “urban� runoff--street water contaminated by pesticides, used motor oil and other household pollutants that flows into storm drains--is important because of the growing contamination of Santa Monica Bay.

The city of Los Angeles is under an order from the federal Environmental Protection Agency to study ways to clean up its urban runoff. But Gold said no one is really looking at the use of wetlands for urban runoff treatment.

Gold said studies have shown that wetlands can remove up to 90% of some chemicals in water--including nitrogen and phosphorous--and 90% of some suspended solids, coliforms and other organic materials.

He said studies on the removal efficiencies of wetlands for heavy metals and oil and grease are not extensive, but that one study of a cordgrass-dominated salt marsh showed that metal concentrations from wetland effluent were 15% to 32% lower than when the water entered the wetland.

Gold said the constant tidal flux and water flow would prevent an accumulation of heavy metals in the basin and in the vegetation. He said storm flows would scour the basin bottom and remove a large portion of eelgrass, where the heavy metal may accumulate and eventually break down into less harmful concentrations.

The Oxford Flood Control basin had been the unofficial home to discarded pet ducks, chickens and rabbits for 10 years. In 1982, a group of volunteers began feeding and caring for the animals.

However, after years of complaints from nearby residents of noise and offensive odors, county officials in January ordered all the animals removed.

County officials also were concerned that burrowing animals were eroding the banks of the basin, and that animal droppings were contributing to pollution of the marina’s only swimming beach.

Nearly all the animals and birds have been removed, most of them to county parks, to Bourdon said.