A whole new set of stormwater regulations is about to wash over cities and counties, especially in Southern California. At first blush, these new regulations may seem most onerous on new development, which will probably have to meet very demanding onsite detention and water quality standards. But it might also mean retrofitting older urban neighborhoods – and using existing parks and other open spaces, including cemeteries, to help water quality in those neighborhoods.
Bottom line: In an infill setting, every piece of public works – hardscape or softscape – has to serve several different functions.
That, at least, was the message from Los Angeles city and county officials at a meeting on water and land use last week. The meeting, attended by about 100 planning and water folks from various agencies in Southern California, was sponsored by the Local Government Commission and held at the offices of the California Endowment adjacent to Union Station in downtown L.A.
Paula Daniels, a member of the City of Los Angeles Board of Public Works, spoke specifically to her department's "Green Streets" program, which is learning lessons from Portland, Seattle, and elsewhere to use streets and sidewalks for better percolation. One example is the "bumpout," which cuts into a street and has a vegetative garden that attracts runoff. She said an 11% reduction in impervious surface can reduce in runoff by up to 90%.
"Most pollution actually comes from automobiles," she said. "Not only do they drive land use decisions, but they also have air pollution impacts. You know about air pollution. But the same pollutants end up on the streets and end up being carried off into the ocean through the streets, which are a rapid conveyance system for pollution. …These vegetation solutions – the roots, the leaves – they sequester carbon, they take in stormwater, they convert what comes from the automobile into nutrients."
Daniels pointed in particular to a green project on Oros Street, near the interchange of Interstate 110 and Interstate 5 (not far from Dodger Stadium). The Oros Street project marks the first time that the City of L.A. constructed "stormwater gardens" that filter most pollutants running off nearby houses and streets.
- Bill Fulton
