Water in Sonoma County today is considerably less polluted by wastewater discharges than in the past, but contamination from a variety of uncontrolled sources persists, according to recent state and local reports.
The mass fish kills witnessed in the Petaluma River and Laguna de Santa Rosa as late as the mid-1980s are no longer common occurrence, according to accounts from Regional Water Quality Control Board staff. Those crises--caused by summertime releases of sewage and excessive amounts of chlorine in effluent--have abated with seasonal limits for discharge and better wastewater treatment. But the volume of municipal wastewater releases is growing, and the cumulative effects of nonpoint pollution sources still adversely affect water quality, fish and wildlife.
Types of water pollution in Sonoma County vary with land use. In rural areas, leaking septic systems and piled animal wastes have leached bacteria and nitrates into groundwater. Common farming practices have a cumulative impact on streamways: water diversions cause low water levels and intensify pollution; animal wastes feed aquatic plants, algae, and bacteria, which in turn consume dissolved oxygen needed by fish. Decaying wastes also produce ammonia, toxic to fish; and eroded soils muddy the water. Both agricultural and urban activities contribute pesticides and herbicides. Urban centers add large quantities of wastewater and street and storm drain runoff. And in areas of commerce and industry scattered throughout the county, toxic spills and leaks have seeped underground.
Water quality and water rights management is based on state and federal legislative acts passed during the late 1960s and early '70s, directing regional boards to identify and enforce the beneficial uses of water within their jurisdictions. In Sonoma County, two water board regions adjoin one another: the North Coast Regional Water Quality Control Board holds jurisdiction over the Gualala, Russian River, and lesser coastal drainage basins; the San Francisco Bay Regional Water Quality Control Board has guardianship of the Petaluma River and Sonoma Creek watersheds feeding into San Pablo Bay.
As part of their job, water quality control boards grant discharge permits, monitor dischargers--both those releasing as point sources (via pipe) and nonpoint sources (via runoff)--and track water quality trends. Between 1976 and 1994, the number of waterbodies routinely monitored for water quality in the county rose from four to 52.
Water rights are granted by the state Water Resources Control Board.
The extent of water quality monitoring in Sonoma County has expanded since the early 1970s. A significant portion of our streamways is known to be polluted to some degree.
In the state's 1994 biennial water quality report, regional staff monitored and reported on 413 miles of streamway in Sonoma County, as well as 13,998 acres of open water and 277 square miles of underground water stores. Of these, the greatest portion meets clean water standards. Serious but localized contamination of open water bodies and groundwater exists, but most known degradation occurred in streamways.
Of total streamway mileage monitored in Sonoma County, one-third (142 miles) was considered of good quality--supporting or enhancing its designated beneficial uses--in the state's most recent biennial water quality report. Thirty-nine percent (161 miles) of streamway received intermediate ranking: either maintaining beneficial uses with occasional degradation, or showing
inconclusive evidence of impairment. One-fifth (84 miles) of the county's streamway was rated as impaired, falling short of standards for beneficial use.
Individual streamways rated as follows:
ï Similar conditions, compounded by urban runoff and rural and urban wastewater disposal problems, afflict the Laguna de Santa Rosa and, potentially, water quality downstream in the Russian River. All 26 miles of the Laguna are considered impaired.
ï Numerous activities spanning the length of the Russian River threaten to compromise its quality, but current ratings are good, reflecting improvements made to discharges over recent decades.
ï To the south and east, both the Petaluma River and Sonoma Creek are subject to eutrophication, becoming progressively more conducive to plant growth than to fish. In the Petaluma River, fish populations are declining in part because of filling and dredging of wetlands and diversions upstream. Twenty miles of the river are rated impaired; the remaining five, rated intermediate.
Bacteria counts exceed standards in Sonoma Creek, indicating the presence of other nutrient-related pollutants, such as ammonia and nitrates. The condition of lesser streams in the south county is unknown. Fourteen miles of the 23-mile Sonoma Creek are rated impaired; the remainder, intermediate.
ï At the county's northwest edge, sediment generated by poor logging practices of earlier decades continues to wash into the Gualala River, reducing steelhead counts and affecting water supplies for residents of Gualala and Sea Ranch.
All large waterbodies with the exception of the impaired portion of the Estero Americano received a "good" rating from water quality staff. Bodega Bay and Bodega Harbor, also rated as good, are threatened by the poor water quality of their tributaries, by fishing industry discharges, and by offshore spills. Sedimentation in the Russian River Delta threatens fish populations.
Perhaps the most pernicious water quality problems in the county affect portions of its groundwater. Staff estimates that about 4.7% (13 square miles) out of 277 square miles of monitored groundwater rank as impaired. This includes an area beneath the Santa Rosa plains:
ï Nitrates from intensive agriculture in the southern central plain pollute groundwater.
ï Leaking underground fuel tanks and, frequently, solvent handling problems as well, have tainted portions of the groundwater supply in sites scattered throughout the county, fouling domestic wells and threatening potential municipal water supplies in the Alexander Valley, Annapolis, Gualala, the lower Russian River, Bodega Bay, Healdsburg, Cloverdale, Windsor, the Santa Rosa plains, Petaluma, and Sonoma.
ï In Cloverdale and Windsor, wood treatment chemicals have entered groundwater; waste oil appears in places under Windsor, as well as beneath Healdsburg.
State Water Resources Control Board; North Coast Regional Water Quality Control Board; San Francisco Bay Regional Water Quality Control Board.
The North Coast Regional Water Quality Control Board staff, writing in its 1993 interim report on Russian River water quality monitoring, said that river water quality has improved significantly since monitoring began in the early 1970s, particularly in terms of nutrient concentrations and bacterial counts. The NCRWQCB credited the improvement to reduced periods of discharge and higher levels of treatment for municipal and industrial wastewater, and better dairy waste management practices. However, pollutant levels still exceed
standards at times, especially for bacteria measured at recreational spots during recreational use. (Evidence suggests that bathers are the chief contributors to this problem, according to staff.)
Nutrient pollution still reaches unacceptable levels on occasion in the Laguna de Santa Rosa, a tributary, and in the river just downstream of their confluence.
In other studies, researchers found that excessive plant growth in the river is more likely caused by nutrients in bottom material rather than waterborne nutrients. Concerning gravel mining, staff said that excavations along the river may indeed affect water and groundwater quality and flow patterns--but that it was "difficult to substantiate" to what extent.
In its study of the City of Santa Rosa's regional wastewater system discharges to the Russian River between 1987 to mid-1990 (Analysis of Compliance), the NCRWQCB concluded that releases were of safe quality, with the exception of a high trihalomethanes count in March 1989 that was more than double the state health regulation of 100 parts per billion for drinking water supplies. (Trihalomethanes, a product of conventional wastewater disinfection procedures, are carcinogenic.) Trihalomethanes were detected in the wastewater consistently, usually at levels of around 30 ppb. Six other toxic organic chemicals appeared in the sampling on single occasions in low concentrations. Only copper appeared routinely in concentrations above recommended toxicity levels for freshwater aquatic life, apparently drawn into water supplies from residential copper piping. Brief exceedances of limits for bacteria and solids did not constitute a threat to public health, researchers said.
A research group led by Charles V. Logie, writing in Comparison of Wastewater Discharge Rates for River Flows For California Dischargers in 1989 found the Santa Rosa regional system to be among the few of its kind limited to discharges of less than one percent of average annual river flow. While it is currently the largest discharger in the Russian River basin, growth estimates for the communities of Windsor, Healdsburg, and Larkfield-Wikiup indicate that the cumulative releases from these and other river dischargers will match or exceed the volume of Santa Rosa's effluent releasees in the near future.
Poor water quality persists in the Laguna de Santa Rosa despite heightened clean up efforts that succeeded in reducing nutrient levels by half in recent decades. In its final report on the "Investigation for Nonpoint Source Pollutants in the Laguna de Santa Rosa, Sonoma County" (1992), the North Coast Regional Water Quality Control Board staff found that non-point sources are still a major contributor of pollutants in the Laguna, and cited three sources: urban runoff; rural septic system failure; and agricultural runoff from livestock and dairy farms, newly-fertilized fields, and irrigation using urban effluent.
Monitoring revealed levels of un-ionized ammonia (a product of waste decomposition) at times exceeding EPA criteria for the protection of aquatic life, as well as water temperatures too high at times for cold-water fish (possibly due to loss of riparian forest), and sediments overladen with nutrients. In the Laguna's urban tributaries, heavy metal pollution, including lead, zinc, copper, and chromium (some from natural sources), exceeded protection standards for aquatic life during the first hours of heavy storms. The presence of motor oil, diesel fuel, and some pesticides was also detected on occasion in "relatively low concentrations."
The Laguna has been frequented by steelhead and other cold-water fish, and Santa Rosans are working to restore the status of Santa Rosa Creek, a Laguna tributary, as a steelhead stream. Additional remedies include a program of voluntary compliance for dairies and new local urban runoff control programs, including a demonstration project operated with the help of high-school students.
Large-scale land-clearing, grazing, and timber harvesting have had "severe environmental and economic effects" on four coastal watersheds in Sonoma County, according to the Draft Sonoma County Coastal Wetlands Enhancement Plan, produced by the state Coastal Conservancy and Circuit Riders in 1987. Researchers found that extreme soil losses had reduced tidal, freshwater, and riparian habitat, and diminished productive agricultural acreage throughout the Americano Creek, Salmon Creek, Willow Creek, and Cheney Gulch basins. A single gully in the Americano Creek area disgorged 4,000 tons of sediment annually, contributing to flooding around Bloomfield and Valley Ford. Because of sedimentation and low water levels, the creek is no longer navigable.
Sedimentation in the Salmon Creek estuary has reduced its capacity by 25%. Past logging and heavy storms have partially filled the Willow Creek channel and surrounding wetlands. In Cheney Gulch, erosion over the years has generated enough sediment to close the gulch to navigation and fill 35 acres of subtidal habitat in Bodega Harbor, requiring costly dredging to keep the channel open.
Roughly 133,791 acres of county flatland were subject to excessive erosion in the early 1980s, according to the Sonoma County Soil Resources Inventory, the Soil Conservation Service's most recent soil inventory. Another 41,000 acres were subject to deep gully erosion, according to the report; about 5000 acres were prone to flooding and sedimentation caused by upstream erosion. Soil conservationists attribute local soil losses largely to land-clearing, including vineyard development on steep hillsides (which shed 20-250 tons of soil per acre per year), overgrazing, ranchette and road development, timberland access roads and timber harvesting.
USDA officials observe that urban uses now cover much of the county's prime agricultural land, and that agricultural production has dropped as a result of this, as well as in response to inflated property values in areas adjacent to cities. Urban expansion is expected to cover 18,000 acres by the year 2000.
Researchers led by David W. Smith, writing in History, Land Uses and Natural Resources of the Laguna de Santa Rosa, (a.k.a. Laguna Characterization Study) of 1990, reported that urban acreage in the Santa Rosa area is roughly equivalent to the amount of land that was under agriculture in the same area around the years 1910-20. Pesticide and chemical use in modern urban areas often far exceeds agricultural use on a per-acre basis, they noted; herbicide uses include private landscaping and county flood control channel maintenance.
Sedimentation is occurring more rapidly than anticipated in Santa Rosa area flood detention basins, possibly as a result, in part, of rapid development, according to the city's 1990 general plan EIR. The increased amount of pavement has accelerated and increased runoff from storms, further eroding natural stream channels. Private owners are losing property and stream
banks are slowly collapsing along Spring and Matanzas creeks. Downstream, sedimentation has reduced the Laguna's capacity to hold Russian River floodwater.
Although the plan calls for more natural stream restoration, the cumulative effects of added development may induce the construction of more artificial drainage and flood control channels instead. More development will also increase water pollution and reduce groundwater recharge rates in the city by a total of roughly 31% in urban zones and 11% in outlying areas, according to planners.
A total of 53 public water supply wells in Sonoma County were known to be contaminated with toxic organic chemicals in 1990, according the state's annual Well Investigations Program report of that year. Most of the wells (36), were within Santa Rosa, seven of them listed as state superfund sites. Among the most frequently-occurring of the 37 chemical compounds found in the wells, trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) led the list, followed by chloroform, freon, and benzene. Some of the highest concentrations occurred in Bodega Bay (chloroform at 110 parts per billion), and at a building supply store in Santa Rosa (benzene, 1300 ppb).
At least 697 underground tanks containing hazardous substances are known to have leaked in Sonoma County, according to the State Water Resources Control Board's 1992 Report on Releases of Hazardous Substances from Underground Storage Tanks, an annual report. Leaks of gasoline, waste oil, solvents, or other substances from one or more tanks have contaminated groundwater on 310 sites in the county, affecting drinking water supplies in 15 instances. Remedial action has been in progress.
State researchers monitoring toxics bioaccumulating in the Russian River watershed found three heavy metals present at levels in excess of international standards, while some other toxins appeared in amounts higher than average, according to data published by the State Water Resources Control Board in its Toxic Substances Monitoring Program: Ten Year Summary Report; 1978-87 (1990) and annual data reports from 1991, 1992, and 1993.
Toxics are unlikely to appear in detectable amounts in surface water "grab samples," but do show up over time in some aquatic organisms.
In tests for substances in fish and shellfish tissue taken over 13 years' time, mercury levels exceeded standards in fish taken from Lake Pillsbury in 1981, and again among Pillsbury, Mendocino, and Sonoma lakes and Russian River samples between 1989 and 1993. Elevated levels of mercury not above standards in fish tissue have also been found in Mark West Creek and the lower river. Selenium in excess of international standards appeared in tissue samples taken from the Russian River, Laguna de Santa Rosa, and Santa Rosa Creek in 1987. And sampling conducted in the lower Russian River had also revealed chromium above standards in 1978; elevated levels of chromium not above standards were again found in samples from the Russian River at Oddfellows, Mark West Creek, and, in later testing, Sonoma Creek.
Mercury and chromium naturally occur at high levels in the local environment.
The central county river was the only Sonoma County location to be included in the testing conducted by the state Water Resources Control Board until the early 1990s.
Other toxic substances found to be bioaccumulating in the river watershed include: arsenic, lindane, nickel, DDT, and lead at occasionally elevated levels; chlordane, dieldrin, cadmium, DDE, chlorpyrifos, silver and zinc; and copper in concentrations above those known to bring on chronic poisoning in freshwater organisms. Recent sampling, expanded to include stations in the southern county, revealed elevated levels of nickel, zinc, chromium, arsenic, and copper from among samples taken from the Petaluma River, Sonoma Creek, and the Estero Americano. (Please see Appendix C for more information on waterborne toxics.)
International standards for toxins in fish and shellfish tissue are levels deemed to be dangerous by several nations, but not by the US. In the case of mercury and some other contaminants, federal action levels for edible portions of fish and shellfish have not been exceeded in Russian River watershed samples, but mercury concentrations have exceeded more protective alert levels established by the state of California in 1992. For the protection of aquatic organisms themselves, the federal EPA and the National Academy of Sciences have issued advisory guidelines.
A toxics monitoring program for coastal waters found consistently high levels of cadmium in shellfish collected along most of the state's length, including coastal Sonoma County, between 1977 and 1986, according to the California State Mussel Watch: Ten Year Data Summary of 1988. Researchers for the State Water Resources Control Board found cadmium in excess of international standards in mussels or clams taken from stations at Gerstle Cove, the mouth of the Russian River, Duncan's Mills, Bodega Head, and Bodega Bay. Arsenic levels above the standard appeared in samples taken from Bodega Head in the early 1980s.
Trace metals and organic chemicals found on occasion off the local coast at levels greater than most in the rest of the state included aluminum, lindane, and dacthal. Most of the 13 metals tested for were detected in trace amounts, along with the toxic organic chemicals DDT and DDE, dieldrin, hexachlorobenzene, endosulfan, phenol, chlordane, and nonachlor. However, most of the more than 45 organic chemical compounds and derivatives tested for in Sonoma County did not appear in samples.
(Data reports or annual reports with more detailed comments specific to the Sonoma County coastal watch stations may be available.)
A massive set of studies produced during Santa Rosa's survey of wastewater disposal alternatives in the late 1980s (the Long-Term Detailed Wastewater Reclamation Studies) included the following on the Laguna and southwest county watersheds:
The presence of un-ionized ammonia caused primarily by non-point sources of pollution may hamper steelhead migration in winter and spring in the Laguna, according to researchers led by David W. Smith, writing in Preliminary Laguna de Santa Rosa Discharge Criteria, 1989. They said a change in wastewater discharge from the regional plant could help reduce ammonia levels during these seasons by 15 to 60%. Dissolved oxygen in the Laguna was judged adequate for most species, but possibly too low for salmon-like fish.
The entire Americano Creek watershed appears to be contaminated with fecal bacteria, probably from livestock, said Smith in Preliminary Estero Americano Water Quality Evaluation, 1988. Researchers noted widespread trampling of vegetation in the creek and its estero, causing enough sedimentation to alter
the estero wetlands and reduce its tidal capacity, probably affecting the types of plants and animals found there.
Some areas of the watershed appeared to be productive fish nurseries, researchers said.
Barren land in the Estero Americano expanded from one to about 35 acres between 1977 and 1989, both because of trampling and because of high soil salinity brought about by the lack of freshwater inflows during summertime, according to H.T. Harvey, et al, in Wetlands in the Estero Americano and Estero de San Antonio. Researchers said that they looked for, but did not find the endangered California Clapper Rail, typically a resident of natural estero habitat.
The EPA criteria for the protection of aquatic life was at times exceeded by un-ionized ammonia, copper, and zinc pollutants in the waste-loaded runoff of Americano and Stemple creek watersheds, with copper concentrations topping the standard as much as 67% percent of the time during sampling in the Americano, reported Marcie L. Commins, et al., in Estero Americano and Estero de San Antonio Monitoring Program: 1988-1989 Results. The copper found in the watersheds may have its source in copper sulfate hoof baths used to control fungus on dairy cattle, or in applications of copper used to kill mollusks in farm ponds
The tidewater goby, normally found in coastal esteros, appeared only rarely in the upper reaches of the Estero Americano. Due to habitat loss and degradation, the goby has nearly disappeared from California, and is now a candidate for state listing. Researchers said the diversity of organisms in the estero decreased with distance from the ocean as ammonia concentrations in the water rose. Spawning populations of steelhead and coho salmon apparently no longer frequent the two streams.
In his Draft Water Quality Results from Quarterly Groundwater Sampling, researcher Gerald Vogt said levels of indicator bacteria, dissolved solids, and nitrate were higher in groundwater samples from the areas of Stemple and Americano Creeks and Two Rock than in groundwater around Valley Ford and Bloomfield in 1988 and 1989. Vogt's team suggested that runoff or infiltration from agricultural feedlots and dairies might be the cause of the higher readings. Well tests yielded detectable but safe levels of arsenic, barium, iron, lead, and zinc, manganese, copper, silver, and selenium.
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