That's what happened at the southern end of the Napa Valley in the mid-19th century when farmers drained tidal lands for hay and cattle, then again in the mid-20th century when high-salinity ponds for solar salt production were built.

Until recent times, such devastating environmental makeovers were routine. Man manipulated nature for economic gain and called it progress. It didn't matter that hundreds of species were being tossed out of their ecological niches.

"At the time, swamps were evil," said Karen Taylor, a wildlife biologist with the California Department of Fish and Game. "A mosquito-breeding habitat."

The federal government even rewarded settlers for turning wetland into farmland, Susanne M. von Rosenberg, an environmental consultant, said. "If you reclaimed an acre and kept it in production for five years, the land was yours."

During the era when landowners had blank checks to do as they wanted, Napa's wetlands declined from 18,000 acres to 4,300 acres by the mid-20th century, resource agencies report.

Then something radical happened. Society did a 180. Wetlands went from being regarded as stinky swamps to ecological wonders, extolled for incubating native species, cleansing water, providing flood control.

Today, it practically takes "an act of God" for a landowner to convert wetlands, von Rosenberg said.

This new thinking is vividly on display at the old Cargill salt ponds, east and west of the Napa River near American Canyon, which are part of the largest wetlands restoration on the West Coast.

Cargill Salt once harvested a quarter-million pounds of industrial-grade salt annually from 11,000 acres of ponds. Viewed from the air, these ponds were a brilliant red, orange and chartreuse mosaic.

But the ponds were as toxic as they were pretty.

Native fish die off before water reaches two times natural salinity. These ponds were hundreds of times more salty, von Rosenberg said.

About the only species that thrived in salt ponds were brine shrimp and brine flies, von Rosenberg said. That left hundreds of birds, fish and mammals looking for new habitat.

When Cargill shut down in 1989 after losing its major customer, Dow Chemical, resource agencies were handed a rare environmental restoration opportunity.

The state bought Cargill's westside acreage in 1994, the eastside land in 2003. Today, environmental groups are working pond by pond to restore this property to its natural state. So far, more than 5,000 acres are on the path back to wildness.

This is a long-range $60 million effort, with major support from Fish and Game, the National Oceanic and Atmospheric Administration, which got an $8 million federal stimulus grant, Ducks Unlimited and private foundations.

Last month, levees protecting 1,400 acres near Green Island Road on the east bank were opened, starting a restoration process that will take decades.

The land has subsided several feet since pre-settlement times. It will take years for natural sedimentation to fill in this soils deficit, von Rosenberg said. The state considered bringing in soil to speed restoration, but this was deemed too expensive.

The subsidence would have been worse but for the salt ponds, she said. Former wetlands in the South Bay that have been farmed for 100 years have dropped 10 to 15 feet, she said.

Dramatic changes are visible at a westside pond whose levee was breached in 1995. "It went from alkali flat devoid of vegetation to 95 percent vegetation. Now it's amazing," said Tom Huffman, a wildlife habitat supervisor with Fish and Game.

Unless you're a boater, it's hard to appreciate how vast these restored wetlands are, Huffman said. "You might as well be in the middle of the Everglades. You can go most of the day without seeing a person," he said of his boating excursions.

Humans may be scarce, but waterfowl are not. South Napa's wetlands are part of the Pacific Flyway. They are visited by hundreds of thousands of migrating birds annually.

The state has spent millions of dollars on studies to make sure levee breaches are done prudently, von Rosenberg said. Restoring ponds is a delicate business. Fish and Game doesn't want to dump a toxic load of saline water into the Napa River and its sloughs.

Studies have looked at piping in treated wastewater from Sonoma and Napa to speed up the flushing of salt, but this would be costly, experts said.

The public can already hunt and fish in some parts of the westside wetlands. On the east side, a public trail is expected to be open in 2011, connecting the new Green Island wetlands to American Canyon.

Green Island will have a public parking lot and a spot where kayaks and hand-carried boats can be launched.

Restoration is a work in progress, Huffman said. What man did over the past century and a half cannot be instantly undone.

Come back in 100 years, Huffman said. "They won't be able to see what was here originally, but they're going to see man's best attempt to recreate it."#

http://napavalleyregister.com/news/local/article_4dcf4dea-b96f-11df-8d66-001cc4c002e0.html