The economic and political challenges of urban stream-restoration work are daunting, but the long-term ecological costs of inaction are even worse. A study conducted between 2004 and 2006 by the San Francisco Regional Water Quality Control Board found that nearly all of the region's creeks showed impaired biodiversity. In February, the regional water board declared 26 urban waterways chronically polluted by toxins and garbage. The pollution concentrates at the ends of the watersheds, along the tidal lowlands, in places like North Richmond. Over time, tides and currents flush the most buoyant material through the Golden Gate. Some of the material migrates to the Texas-sized "Great Pacific Garbage Patch," a soup of plastic fragments and debris that languishes 1,000 miles off the California coast.

In San Francisco, where nearly all of the city's streams have been buried in pipes and tied into the city's sewer system, stormwater presents an even greater dilemma. When heavy rains overwhelm the system's capacity, sewage overflow runs into San Francisco Bay. Last year alone, over 800 million gallons of untreated sewage flowed into the ocean and bay.

Rosey Jencks, a watershed and stormwater planner at the San Francisco Public Utilities Commission, is exploring the feasibility of small, low-impact projects such as vegetated medians, permeable pavement and daylighting stretches of streams. If water and pollutants are absorbed into the ground, the amount of runoff entering the sewers is decreased. "These projects allow you to take the pressure of the system without 100 percent going back to the old hydrology," says Jencks. To date, however, the city has only a handful of demonstration projects, including a parking lot near Lake Merced that shunts runoff into grassy medians.

These fledgling efforts are about more than protecting the Bay's marine ecosystems. Every gallon of water kept out of San Francisco's east-side sewer system is a gallon less directed to the Bayview District, the city's poorest neighborhood and site of its largest waste-treatment plant. The Southeast Plant processes almost 80 percent of the city's sewage and stormwater, much of it pumped uphill from other urban drainages. Though the city has remedied some of the problems, Southeast is still locally notorious for odors, flooding and ominous emissions from its stacks.

"In San Francisco, we're constantly reminded we're this clean, green city," says Marie Harrison, a Bayview-Hunters Point activist and resident. "I laugh. If we're leading the way, everyone else must be half dead."

Back on Wildcat Creek, near Verde Elementary, Bradt and I come upon a three-channeled raceway installed by the Army Corps of Engineers. Its vertical concrete walls are tattooed top to bottom with graffiti. (I pause to decipher one haiku-like snippet, which reads: Respect / Train Wit No Love / Richmond.)

In spite of the heavily engineered aesthetic, Bradt says, Wildcat Creek is one of a handful of Bay Area streams that still provide habitat for endangered steelhead. (Locals have even reported fish farther upstream, sheltering in submerged shopping carts.) Richmond's estuaries also remain important stopovers for migrating birds on the Pacific Flyway, he says. But when you're actually out here, it's hard to feel hopeful. We hop a small wire fence into the concrete streambed. The middle channel carries a swift, shallow flow of water, designed to allow spawning fish upstream. Though we are in the midst of steelhead spawning season, there are no fish. Even if there had been, the channel would probably have been impassible: It's clogged with a mattress.

On our way back to the car, parked near the entrance to Wildcat Creek Marsh, Bradt mentions the importance of keeping "eyes on the creek," inspired by the urbanist Jane Jacobs' notion of "eyes on the street." "The idea is that a community that uses its local waterways for recreation is far more likely to become active in protecting them," says Bradt. But as we approach Richmond Parkway, there's not a recreationist in sight. The path along the creek under the roadway is blockaded, as it is almost year-round, with floodwater, mud and trash, and we are forced into the street to contend with a torrent of traffic.

The eyes on the creek have been steadily increasing, however, as East Bay activists and residents rally local support for the environment. In 2006, with the election of Gayle McLaughlin, Richmond became the largest city in the country with a Green Party mayor. Twice in as many years, community members have marched to protest the Chevron refinery's frequent "flaring" events -- which emit heavy black smoke and toxic gases -- as well as the company's proposal to expand its facility to refine low-grade crude oil. In 2006, the community successfully defeated Chevron's plans to dredge Wildcat Creek Marsh for a deepwater shipping channel.

At the federal level, the new presidential administration has made environmental justice a distinct part of its vision. In March, President Obama appointed Van Jones, the Oakland-based author of The Green Collar Economy, as his green jobs advisor. Jones, who has quipped that a nationwide environmental revitalization should begin with "greening the ghetto," believes that money allocated for environmental protection can spur a green jobs movement in disenfranchised communities.

Many early efforts to introduce "green sector" jobs in the East Bay have focused on alternative energy. In 2008, for example, the Oakland Green Jobs Corps, part of a group founded by Van Jones, announced a program to train 40 inner-city recruits for "solar panel installation, energy efficiency and green construction." However, Ian Kim, a director of the Corps, sees another nascent effort in the East Bay, based around water efficiency and supply protection. "In California, water scarcity is an issue. We spend almost 20 percent of our energy just moving water around," says Kim. "We are beginning to reframe and rethink how water and energy are related." He points to water efficiency upgrades -- the installation of low-flow appliances, graywater recycling units and rainwater retention systems, for instance -- as job markets that may emerge in underserved neighborhoods. Some call these socially responsive new jobs "blue-green" work -- "blue" as in blue-collar labor.

To see how such jobs might play out on urban waterways, I meet with Sergio Brambila, a site director for the Oakland-based Civicorps. (Civicorps, which is modeled on the California Conservation Corps, seeks to recruit at-risk inner-city youth.) Many of his crew are dropouts or are on parole or probation. Brambila and his crew are working with the Urban Creeks Council on a restoration project on Rheem Creek, which runs through the Contra Costa College campus in San Pablo. As we talk, Civicorps members claw at the ground with picks and heavy rakes, removing trash, ivy and invasive black acacia tree runners from the creekbed.

Brambila reminds his recruits to dig deeper, and to look carefully for weeds left in the upturned soil. "Break that ball up. Pull out the roots. Sift through it!" he urges. Brambila says the corps provides an avenue for work and also a means of stanching the flow of local youth into the criminal justice system. "That's what is beautiful about the corps. You get to be in an environment where you can teach them about their community -- and about the importance of stream restoration, water quality and loss of habitat," says Brambila. "It then becomes their choice about whether they're going to use it and abuse it or leave it a better place."

A young man from East Oakland named Freddy Bowman props his chin on his shovel and looks out over his work. "I'm here to get my high school diploma and finish my portfolio," says Bowman. "Maybe I can get a little money in my pocket, too, and stay out of jail." After five months in the classroom, he says he's happy to finally be out in the field working. Until he gets his diploma, however, Bowman can't get onto a fire crew or into the recycling program that he says drew him to Civicorps in the first place. Then he politely excuses himself; he has to get back to work. A hard afternoon lies ahead. "We've got to get all this ivy out of the creek, so it doesn't grow all over and choke the trees. So they can breathe."

Jeremy Miller is a Denver freelance writer. His recent work has appeared in Harper's, the San Francisco Chronicle, the Boston Globe and the New York Times' Green Inc. blog. 

This story was supported in part by the Kenney Brothers Foundation.