January 23, 2003

By Stuart Leavenworth

Bee Staff Writer

916-321-1185

sleavenworth@sacbee.com

The Sacramento Bee

Sacramento, California

To submit a Letter to the Editor: editor@sacbee.com

It's an environmental crusade that ranks with saving the Everglades. In coming decades, ecologists hope to restore up to 70 square miles of wetlands in the Sacramento-San Joaquin Delta, transforming several farm-tilled islands back into habitat for fish and fowl.

But the dream is being tripped up by a troubling scientific finding: Wetlands release vast amounts of natural organic compounds that, while good for the ecosystem, are bad for cities that suck their drinking water out of the Delta.

That means that state and federal authorities could worsen the drinking supplies of 22 million Californians if they haphazardly restore wetlands in the West Coast's largest estuary.

"This is an important issue as we consider tripling or quadrupling the amount of tidal wetlands in the Delta," said Brian Bergamaschi, a U.S. Geological Survey geochemist who has been investigating the impacts of wetlands restoration. "This doesn't mean that you can't restore wetlands in the Delta. But you have to be careful about how you do it."

Unveiled at a science conference in Sacramento last week, the findings by Bergamaschi and other USGS scientists pose a policy conundrum for Cal-Fed, an $8.5 billion state and federal effort aimed at revitalizing the Delta.

Since it was launched in 1994, one of Cal-Fed's top goals has been to restore some of the Delta's marshes and swamps, three-fourths of which were converted to farms starting in the late 1880s.

But that goal could be in conflict with another Cal-Fed priority -- making the Delta healthier for Bay Area and Southern California cities that have tapped this brackish expanse of water.

"This is an excellent example of the kind of tradeoffs we face," said Tim Quinn, a vice president of the Metropolitan Water District of Southern California, a supporter of Cal-Fed. The Delta serves so many masters, he said, "It is hard to make everyone happy."

At issue is a fundamental component of all wetlands -- dissolved organic carbon -- also known as "muck" by some scientists. Marshes and swamps release these carbon compounds as their plants and microbial creatures die and decay. In a natural setting, the carbon is then recycled and used by other plants and animals, making it an important part of the food web.

Dissolved carbon, however, causes trouble when it interacts with chlorine -- the main chemical used by cities to rid their drinking water of bacteria and viruses. Operators of drinking-water plants can inadvertently create trihalomethanes -- a family of compounds suspected of causing cancer and reproductive problems -- when they use chlorine to treat raw water that is rich in dissolved carbon.

Over the last decade, water officials in Southern California, Contra Costa County and other Bay Area communities have struggled to reduce their trihalomethane levels.

Five years ago, a state study revealed mothers who drank elevated levels of trihalomethanes had a miscarriage rate nearly twice that of other pregnant women. As a result, some cities have spent millions on alternatives to chlorine treatment. Others have tried to pump their water from the Delta during spring months -- when carbon compounds are at their lowest -- although that's when smelt and other threatened fish can easily be sucked into the pumps.

Now, some city officials fear they could face even more headaches if wetlands are widely restored in the Delta. Part of their concern comes from USGS studies conducted on Twitchell Island, a state-owned island, four miles south of Isleton, where land managers created a pair of 7-acre wetlands in 1997.

Using direct and indirect measurements, scientists have monitored how much dissolved carbon is flowing from these two wetlands in runoff and groundwater. So far, their research suggests the wetlands are producing from seven to 17 times more dissolved carbon than the amount generated by the same acreage of nearby farm fields.

"When we started our studies, I was surprised," said Roger Fujii, a USGS scientist who has led the research. Although wetlands have long been known to generate lots of "muck," many had assumed that farmlands in the Delta were a greater generator of carbon.

Presented Jan. 15 at the Cal-Fed Science Conference, the Fujii and Bergamaschi findings stirred debate among the assembled researchers. Some questioned whether USGS studies were ignoring the impact of dairy farms and other agriculture that wasn't covered in the study.

Others said the findings seem sound but still don't answer all questions about restoring tidal marshes and other types of wetlands in the Delta.

"This alerts us to a potential conundrum," said Sam Luoma, chief scientist for the Cal-Fed program. "But before we react to it, we need to find out the full impact."

Part of the problem is that dissolved carbon is generated not only in the Delta, but in aqueducts and reservoirs that cities use to move their water out of the estuary, said Kim Taylor, science program manager for Cal-Fed. Upcoming research, she said, will examine how cities can prevent these carbon buildups as they move or store their water prior to chemical treatment.

John Cain, an ecologist with the Natural Heritage Institute, an environmental group, said the downside of restoring wetlands also must be measured against the benefits. Aside from providing habitat, wetlands help the Delta filter out pesticides and other pollution that now flows into the San Francisco Bay.

Revegetation could also prevent the Delta's islands from continuing to sink or subside, Cain said. Over the last century, some islands have dropped 20 feet or more, making them increasingly vulnerable to a mishap or a natural disaster.

"During an earthquake, you could have several levees breaking at the same time," said Cain, whose group has been trying to raise awareness of the subsidence problem. If several levees broke, fresh water would inundate the bowl-like islands, in turn causing saltwater to move farther up the estuary and threaten urban drinking supplies.

Plenty of interests are keeping a watch on Cal-Fed's examination of wetlands and water quality, which has so far received $6.8 million in funding. Urban agencies want more water and less pollution. Farm businesses want to limit the conversion of agricultural land, while wildlife advocates want more wetlands, faster.

Luoma says the wetlands finding, though problematic, builds a case for why Cal-Fed is spending so much time and resources on research, to the consternation of some critics.

"The most important thing is we have been alerted to this," Luoma said. "It is pretty hard to fix a problem if you don't know it exists."

http://www.sacbee.com/content/news/environment/story/5964377p-6923628c.html