By Emily Setzer, INDEX-TRIBUNE STAFF WRITER
Wednesday, November 23, 2005
11.25.05 - Sonoma Creek, that lovely little stream of water that runs through our back yard and hosts the annual show of spawning chinook salmon and steelhead trout, is now polluted with pathogens, according to local water experts.
But the San Francisco Bay Region California Regional Water Quality Control Board is conducting a new study to address the pathogens.
The water board will host a scoping meeting Thursday, Dec. 1, at 7 p.m. at the Sonoma Community Center to present the latest findings on the creek's excessive pathogens - viruses, bacteria and protozoa - that can make humans sick. The board's staff will discuss measures to eliminate or reduce the pathogens to safer levels for humans and wildlife. The staff also wants the public's input on a draft of the water-quality-control plan for the San Francisco Bay basin that will create a strategy to save the creek.
The plan calls for the establishment and implementation of a total maximum daily load for pathogens in the creek that will control the daily amount of pathogens present by determining the level of pollution, establishing water-quality targets, identifying where the pathogens are coming from, and preventing the influx of more pathogens.
After the board presents the pathogen-battling plan, it will conduct an environmental review to examine such factors as water quality, soils, archaeological resources, potential traffic impacts and anything else over which the public expresses concern. While the plan is intended to positively impact the environment, Sandi Potter, engineering geologist for the San Francisco Bay Region Water Quality Control Board, warns that there could be potential disruptions, such as interrupting a certain kind of nesting bird. The staff depends on the local public's knowledge and input.
Sonoma Creek isn't the only local polluted watershed. It joins the Napa River, Petaluma River, Walker Creek, Lagunitas Creek and Tomales Bay, which were all listed as polluted in the state's report under the California Environmental Quality Act.
Many of the pathogens appear to be coming from urban runoff, septic tanks, leaky sewer lines and animal facilities. But the good news is that the problems are very localized, said Potter.
Since pathogens aren't long-term pollutants, once the source is identified and curbed, the pathogens tend to dissipate rapidly in the environment.
"We've been working in the watershed, sampling for different kinds of bacteria that are indicative of animal- or human-waste pollutants. So for people who swim or wade or kayak in the water, we're making sure it's safe for everyone," said Potter.
In addition to addressing the latest pathogen epidemic, officials have already begun studying the creek's high levels of sediments and nutrients. A maximum daily load study focusing on the high sediment levels is already under way and work has already begun for the development of a similar study on nutrients.
"Each problem has its own complexities and takes a certain amount of time to review," said Potter, explaining why each pollutant warrants a separate study.
Human and animal waste, which contains dangerous pathogens, also spurs excess nutrients. The waste contains high amounts of ammonium nitrates, which make nitrogen and phosphorus (also present in fertilizers), which in turn encourage algae growth and deplete oxygen levels - essentially smothering the bottom habitats.
In a report conducted by the water board in 2003, the U.S. Environmental Protection Agency estimated that 40 percent of rivers and streams nationwide suffer from excessive nutrients.
But fish battle with other pollutants that threaten suffocation as well, such as sediment in the form of sand and silt, which smothers aquatic habitats and suffocates fish when it sticks to their gills. For humans, too much sediment causes a loss of municipal water supply by rapidly filling reservoirs and elevating water cloudiness and flooding.
Erosion from roads, agricultural areas, construction and even storm-induced bank erosion causes excessive amounts of sediment.
The biggest problem with sediment pollution is that it has the longest recovery time of the three major pollutants - even if the sources have been stopped - because it takes time to work its way through the tributary systems. That results in long-term effects; too much fine sediment appears to be one of the factors in the declining numbers of steelhead and salmon in Bay Area streams during the past half-century.
The water-quality-control plan should be finalized by December, and more details will be announced at the public workshop, Thursday, Dec. 1, from 7 to 9 p.m. at the Sonoma Community Center, Room 110, at 276 E. Napa St.
More information can be found at the water board's Web site, www.waterboards.ca.gov/sanfranciscobay.
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