The blue-collar neighborhoods of Richmond, North Richmond and San Pablo lie across the bay from San Francisco, on a knuckle of land between San Francisco and San Pablo Bays. The surrounding terrain is rich in contrasts -- sweeping coastlines and smokestacks, rolling hillsides and vast tidal estuaries hemmed in by scrap yards and chemical plants, the elegant Victorian homes of Point Richmond and the abandoned storefronts of downtown. The natural beauty and history of the region rival that of any East Bay community, but Richmond and the surrounding communities have struggled for decades to match the prosperity and livability of Berkeley, 10 miles to the south, or the hamlets of Marin and Napa counties across the blue-green waters of the bay.

The 94801 zip code, which comprises the most polluted and flood-prone stretches of Richmond and North Richmond, is home to six Superfund sites and hundreds of toxic emission sites. The demographic profile of the neighborhood -- 70 percent African-American and 15 percent Hispanic, 40 percent below the poverty line -- closely resembles that of other industrial neighborhoods across the country. North Richmond's creeks, like its residents, have borne the brunt of this crush of waste and industry.

North Richmond's environmental troubles began in a time of prosperity. During World War II, many African-Americans from the South and Midwest came to work in Richmond's shipbuilding factories. Black laborers were segregated in housing built on flood-prone land between San Pablo and Wildcat creeks. Soon after the war ended, returning G.I.s displaced the women and blacks working in the shipyards.

By the early '80s, the neighborhood was 98 percent black, and the poverty rate was nearly 65 percent. Floods ravaged the community almost yearly. In 1982, a neighborhood coalition formed to lobby the Army Corps of Engineers for a flood-control system that would preserve the environment and also jumpstart the area's economy.

North Richmond's residents sought a "natural" approach to flood control: sinuous streambeds and vegetated, sloping stream banks. The greenbelt design would improve the terrain for wildlife and pedestrians and at the same time help impound water and sediment upstream rather than pouring into the marsh. "Even though Wildcat Creek was creating misery for them, overflowing in the streets and bringing mud into their homes, they valued the environment of the creek," says Ann Riley, a river and watershed advisor for the San Francisco Regional Water Quality Control Board and cofounder of the Urban Creeks Council, one of the groups in the North Richmond Coalition. "They had a vision for bringing economic life to the community through commercial recreation, with bait shops, trails and a magnet school for environmental education."

Between 1984 and 1989, the group secured more than $2 million in state and local funds to pay for the work. In the end, however, the design was a compromise. Plans for playgrounds and a streamside amphitheater fell by the wayside. But there would still be a natural channel running between gently sloping banks, interrupted only intermittently by short runs of traditional concrete flood channels.

Today, industrialization, sprawl and pollution threaten to undo such cooperative efforts. Bradt takes me around the lower reaches of San Pablo and Wildcat creeks, pointing out the mounting problems, as well as several of the "demonstration" restoration projects he has overseen. Both streams originate in protected headwater parks southeast of Richmond, wending through wealthier neighborhoods in the Berkeley Hills. Before exiting to the bay, the creeks meander, forming an hourglass-shaped floodplain on which rundown homes, rail yards, a sewage treatment plant and industrial firms huddle together. The endpoint of Wildcat Creek is a 250-acre marsh that provides vital fish and bird habitat. Chevron's massive refinery and tank farm loom over the marsh's southern edge. Here, from 1902 to 1987, Chevron and its predecessors discharged mercury and other toxins. The only landmark higher than the refinery stacks is the 250-foot high ziggurat of the former West County Landfill, which guards the marsh's northern boundary. Locals call the seagull-haunted massif "Garbage Mountain."

Bradt and I press eastward along Wildcat Creek, slogging through weeds and mucky underbrush. The problems with the streambed and the surrounding community become ever more apparent. Bradt points to the Burlington Northern Santa Fe Railroad trestle over the creek: "In high water, that bridge acts as a dam, trapping all sorts of garbage. People also really like to set it on fire." A dizzying array of flotsam lies along the weedy drainage: a transmission flywheel, tires of various sizes, a massive wooden spool, discarded clothes, human feces, hundreds of plastic bags.

Much of the new development here pays little heed to past experience. The low-income housing just west of Rumrill Boulevard sits along a sinuous stretch of Wildcat Creek that the Urban Creeks Council restored in 2006. Bradt says that flood maps clearly show that the building is in the 100-year floodplain. It's also less than 50 yards from the railroad tracks. "Here's a case where creek restoration and low-income housing, two good things, are working against each other," says Bradt, raising his voice to be heard as a freight train pounds by. "Would you want to live here?"