May 25, 2006

Public Park a Marriage of Recreation, Filtration

LOS ANGELES -- A small pocket of land on the banks of the Los Angeles River is working overtime, providing both recreational space to a crowded urban area and acting as a filter for garbage that would otherwise end up in the water.

"Too much of our urban junk, too much of our poisonous runoff gets into our L.A. river," Joe Edmiston, executive director of the Santa Monica Mountains Conservancy, told a Wednesday dedication ceremony for the $3.2 million Marsh Park.

The spit of land, not far from Dodger Stadium, is the first park in Los Angeles to be laid out in such a way as to keep garbage out of the river.

Storm runoff will be naturally filtered through a large, grass-covered water detention basin. From there, the water will seep slowly through the ground, which will separate it from trash and other debris before it reaches the river.

Previously, such runoff would flow straight from the streets to the river, carrying whatever garbage it collected along the way.

Marsh Park is owned by the Santa Monica Mountains Conservancy, which was established by the state Legislature in 1980 to preserve parkland in urban and wilderness areas. Funds from Proposition 13, a $1.97 billion water bond passed by voters in 2000, were used to buy the land and build the first phase of the park, which sits on a half-acre of land.

Two more phases are being planned. And two similar projects up the river are scheduled to be completed later this year.

"The people I represent need parks and they also need clean water," said City Council President Eric Garcetti.

The basin is designed to handle the runoff of a standard storm - one that brings 3/4 of an inch of rain. Under those conditions, it will take 48 hours for all the water to seep through the ground, said Martin Kammerer, the fluvial geomorphologist who designed the park.

Grass and organisms living in the top soil will break down the pollutants left behind, said Kammerer, a physical geographer and hydrologist who specializes in streams.

In the event of a larger than normal storm, any excess water would overflow into the river, which sits between 10 and 15 feet below the basin.

The length of time it takes the water to seep into the ground will also help reduce the risk of flooding during major storms.

"This is going to be the new standard," Kammerer said. "You can clean up the water, and at the same time you have a park amenity."

The Los Angeles River flows for 51 miles from the western edge of the San Fernando Valley to the Pacific Ocean in Long Beach. It drains an area of about 825 square miles.

Most of the Los Angeles River was lined with concrete for flood control between 1935 and 1959. An estimated $110 million has been spent so far on revitalizing the river.


On the Net:

Santa Monica Mountains Conservancy, http://www.smmc.ca.gov