Salmon Creek and the Bodega Bay water system
Full text of protocol below
Posted May 19, 2007 -------- There has been a well in Salmon Creek since the 1950s. The Bodega Bay Public Utility District operates the well now with a history of pumping running back 30 years.
As the District pumps from the well, the water level of the creek drops. Or, that is one of the conclusions of a report prepared by Prunske-Chatham early last year. The District operations chief Rod Huls pointed out the District policy has been to greatly reduce the amount of water pumped during the summer and fall months. The environmental report said the overall level of water flowing to the ocean has dropped significantly compared to what records are available prior to recent baseline studies. That lowered water flow has greatly impacted the ecology of the Creek. The salmonid population has nearly disappeared. Anecdotal evidence is replete with large numbers of salmonid until the 1990s. The extent of the Salmon Creek estuary is tiny compared to its size shown on 1874 (and later) maps.
The Salmon Creek Watershed Council begun in the late 90s is working to restore and repair the long-neglected waterway. The Council commissioned the Prunske-Chatham Estuary study as well as undertaking baseline studies. Volunteers regularly collect samples, measure pollutants and reclaim eroded damaged stream banks.
Just 40 years ago Sonoma County government officials advised farms and ranches to clear the streambed of all debris. Some allowed large dairy lots to drain directly into the stream. Those practices were the best of advice at the time, but are now known to destroy stream salmonid habitats. Steelhead and Coho salmon populations were so low that biologists searched extensively to determine if there were any native populations extant.
In the recent years, lack of rainfall reduced water flow in the creek, coupled with the Prunske-Chatham report, prompted concern that Bodega Bay water pumping was directly destroying the creek. National Marine Fisheries Service investigations resulted in letters advising the BBPUD to revise its pumping policy from the creek.
At last Wednesday’s BBPUD Board of Directors meeting Rod Huls presented a new protocol for the District’s use of Salmon Creek water. Called by the lengthy name, Pilot-scale Study and Interim Operations Protocol for the Bodega Bay Public Utility District Municipal Water Supply Well located adjacent to Salmon Creek, the document calls for ceasing all pumping from the creek when water flow falls below a set level.
The document was prepared by Chuck Hanson, Fisheries Biologist, in consultation with Rod Huls, General Manager for the District. Simply put the District will monitor the flow of the stream through all dry months. When stream flow is below three cubic feet per second (cfs) monitoring will be daily. Between a flow of two to three cfs the district will pump no more than one-eighth the overall stream flow. When creek flows are less than two cfs, the District will further curtail pumping. When the surface flow falls below 50 gallons per minute, pumping will cease. A method of measuring stream flows and calculating surface flows was set up by the document. A cubic foot per second is about 445 gallons per minute. The stream flows would have to return to levels eight times the District’s pumping needs for any pumping to be restarted.
When the District started to investigate modifying its pumping policy – after the Prunske-Chatham report – Janet Mantua, executive officer of the District, pulled the pumping records for the past 30 years for the Salmon Creek well. With exceptions for dry years when water pumping was greatly reduced, the district pumped about the same amount of water in each of the 30 years. Growth of customer water usage was met by additional wells not associated with Salmon Creek.
When the protocol was debated at the District Board of Directors meeting, Mantua said the significantly lower flow of the creek could be traced to increased users upstream. She said recent vineyards pumping from wells directly adjacent to the creek appear to have lowered water levels overall. Over the past 30 years the number of people living within the watershed has significantly increased, many depending on wells.
An effort by the district to exercise its “senior water rights” was determined to be unenforceable. State agencies, though they theoretically have the power, do not have the budgets such actions would require. California water rights law is a minefield with some legal actions taking decades to settle. A senior water right is that which belongs to the earliest water user who takes less than half the water flowing past their point of capture. Upstream users do not have the right to decrease the flow of the waterway below the level of the the downstream users plus the half that should continue to flow past the senior rights holder. Changing environmental concepts have modified the water rights to include the rights of the fish to have water.
The District’s Board of Directors adopted the protocol effective June 1 through June 1, 2010.
"It's great they are responding to local concerns. Excellent," said Abby Myers, member of the Salmon Creek Watershed Council.
The article below appeared in the May 7, 2006 (Vol. 19, #44) Bodega Bay Navigator print edition.
Estuary report draws a crowd
By Joel Hack and JW Sharp
It was a watershed moment. About 100 people filled the Bodega Fire Hall Tuesday evening to hear the draft Salmon Creek Estuary Study.
The presentation of the two-year study wasn’t filled with charts and graphs, dreary language or convoluted science arguments. It simply told the story of how the mouth of Salmon Creek has changed along with the changing land use patterns around it.
An 1877 map of Sonoma County showed the extensive estuary ponds and the open mouth of the Creek. The presentation by Prunuske Chatham, Incorporated (PCI), an ecological engineering firm, began with a history of the human development of the area. The creek and the land surrounding it were used by successive waves of settlers – Native American, Russian, Spanish, European, expansive Americans, explained ethnobotanist Kathleen Harrison. Harrison is collecting oral histories from old-timers up and down the watershed to create a history of local water use.
Without doubt, the report concluded, the estuary is greatly affected by the water users of Salmon Creek. Low water flows in drought year’s distress salmonids. Salmon Creek has lost its coho salmon run in the last 10 years and is left with a dwindling steelhead trout population. The study, funded by the State Coastal Conservancy, is part of a larger community effort to assess the reasons for the decline and to develop an integrated, effective restoration strategy. The study was prepared for the Salmon Creek Watershed Council and the Occidental Arts and Ecology Center.
Project manager and hydrologist Lauren Hammack summarized findings of the two-year study. Her observations and measurements detailed the changes in waterflow and conditions while her colleague Michael Fawcett, an aquatic ecologist, studied the marine life conditions. The study collected data under a very narrow range of weather conditions, yet sufficient to understand the Salmon Creek system and to develop initial habitat recommendations.
Low spring and summer flows increase pool stratification in the estuary and create bottom saline layers too hot and low in oxygen to sustain salmonids. Fish are confined to the upper freshwater layer and to the well-mixed area near the sandbar where they are vulnerable to predation by birds.
Low spring and summer flows also reduce lagoon elevations and delay the breaching of the sandbar. If the sandbar opens after or near the end of the Coho upstream migration period, as occurred in the 2004/2005 winter, Coho have little or no chance of returning to Salmon Creek. Low summer flows also reduce viable salmonid rearing habitat in the main channel and tributaries.
“The lagoon has to breach in time for Coho to enter the stream,” said Hammack. She explained that siltation and water consumption both impact the estuary and increase the impact of low flows during drought years.
A current map of the estuary shows a different picture from that drawn in 1877. Significant amounts of coarse sediment have dramatically decreased the extent and depth of the estuary. During the study period alone, over two feet of sediment was deposited upstream and downstream of the Highway One Bridge. Summer lagoon depths now range from two to six feet compared to six to 12 feet in the 1950s and 1960s. These fine sediments create turbidity levels high enough to destroy habitat and fish life.
There are also a lot more straws sticking into the Salmon Creek watershed, sucking water out for human use. In addition to private wells from Occidental to the Bay, the Bodega Bay Public Utility District has operated wells near the Salmon Creek estuary for 50 years. The wells and pumping records were compared with stream flows and water levels. The data indicate that the water running through Bodega Bay pipes would otherwise flow out of Salmon Creek.
“The daily fluctuation in the level of the estuary corresponded to pumping times,” said Hammack. “The two aquifers are connected.”
She added that all the wells are having an effect on the creek flow. Domestic and agricultural water use in the watershed reduces the amount of water available for upstream and estuarine habitat. Direct withdrawals and near-channel wells upstream of the estuary reduce the streamflow entering the estuary.
Getting an accurate picture of just which wells are having what effect, however, would require an extensive model of the water rights and a water budget for the entire watershed. There are more effective paths to pursue, such as cleaning the creeks of sediment. Until the 70’s, flood control took responsibility for that job; now no one does.
Liza Prunuske, co-owner of PCI, ended the evening with a list of action items, practical steps that can be taken immediately to improve the quality of life for salmonids and perhaps return the creek’s namesake to its native spawning grounds. The first and most obvious is to provide cover for the fish, a place to hide from predators. This can be done with woody debris; recreating historical side channels and reconnecting ponds will also provide necessary habitat.
Human use will have to change in order to maintain sufficient freshwater flows, especially in the summer. Prunuske recommends a water conservation campaign and education of the end consumers. She also said we have to answer the question, “How much water is needed to maintain the health of Salmon Creek?”
The other thing that has to be done, and is being done by many landowners, is to reduce the amount of sediment that enters the creek. Maintaining the quality of the freshwater entering the estuary is key to its long-term health. Best management practices for dairies and vineyards, repairing erosion and improving roadways are all steps that are being taken.
The bottom line is that the problems stem from many sources and there is no one cause that we can latch on to and assign blame. Instead, the denizens of the watershed and the users of its water will have to act in concert to find individual solutions to our common problem: making sure there is enough water for all the end consumers, from tiny fry to giant vineyards.
The estuary report, like the estuary itself, is part of a larger whole. The Coastal Conservancy has been funding many studies of the entire watershed to develop a comprehensive watershed plan. The Conservancy’s Rich Ratecki spoke at the presentation, and he was optimistic about our hopes for success.
“There is a tremendous opportunity for implementation in this watershed,” he told the crowd. Prunuske was even more direct.
“It’s easy to become resigned to our fate,” she said, “but I believe in this watershed.”
The full report is available online at www.bodeganet.com/SalmonCreek/
Pilot-scale Study and Interim Operations Protocol for the Bodega Bay Public Utility District Municipal Water Supply Well Located Adjacent to Salmon Creek
Prepared by Chuck Hanson, Fisheries Biologist In consultation with Rod Huls, General Manager For the Bodega Bay Public Utility District
May 2007
The Bodega Bay Public Utility District (District) operates a series of municipal water supply wells that provide potable water to the community of Bodega Bay. One of the District’s water supply wells is located adjacent to Salmon Creek (Figure 1). Salmon Creek supports a population of anadromous steelhead, in addition to other fish and wildlife species. In the past, the District and others have become concerned regarding the effects of the Salmon Creek well operations on surface waters within the creek, particularly during the summer and early fall under dry hydrologic conditions. Juvenile steelhead over summering within the creek could experience a risk of stranding in the event that well operations result in a reduction in surface water connectivity and availability within the lower reaches of the creek. The District has initiated efforts to identify potential habitat protection actions and measures that would improve the habitat quality and availability for steelhead and other fish and wildlife species within Salmon Creek (Prunuske Chatham 2006) as part of a watershed-level collaborative process.
The Bodega Bay PUD supports actions to enhance habitat quality and availability within Salmon Creek to support steelhead and other aquatic and wildlife resources and has designed the following pilot-scale study and interim operations plan to contribute to the watershed-level habitat enhancement program.
Based upon information contained in a study conducted by Prunuske Chatham (2006), the District intends to implement a three-year pilot study and interim operations plan, beginning in June 1, 2007, designed to protect instream habitat for over summering steelhead within the creek from any adverse impacts of District well operation. This study will also gather additional information regarding the creek at this location. The pilot study includes periodic monitoring of the stage-discharge relationship within Salmon Creek at a transect location immediately adjacent to the existing Salmon Creek well. The stage-discharge measurements would be made over a range of streamflows and would include measurements of creek wetted width, cross-sectional depth and cross-sectional area, and corresponding streamflow to help further characterize habitat conditions for over summering steelhead within the immediate vicinity of the existing well. Stage-discharge measurements will be made approximately 3 to 12 times per year during the low-flow summer season during each of the three-years of the pilot study. The District will monitor water depths and creek flow at the downstream control riffle. The District will monitor the flow on a daily basis when flow is below 3 cfs. Standard Methods and Protocol for Measurement of Stream Flow will be used to measure the flow. Currently, well pump capacity ranges from a high of 0.39 cfs and less depending on water needs of the District. The District will continue well pump operations as long as the creek flow is maintained at least 800% of the well pump usage.
When water depths are 6 inches or less or creek flow is less than 2 cfs, daily monitoring will be conducted to assess habitat conditions (e.g., water depths within the creek) at the downstream control riffle during any time that the District well is in operation. When creek flows are less than 2 cfs the District will be limited to a diversion rate not to exceed 20% of the creek flow at the transect located down stream of the Salmon Creek Well measured in accordance with standard method. Well diversion rate will be reduced in direct proportion to surface flow from 175 gpm to 50 gpm. The District will curtail well operation at or below 50 gpm and switch to an off-site alternative water source that would not have any effect on groundwater or surface waters within the Salmon Creek watershed. When water depths at the downstream riffle exceed 2 cfs or 80% of the well capacity the District may, at its discretion, restore operations of the Salmon Creek well.
The District will prepare annual reports that will be available to the public documenting results of well operations and water depth within Salmon Creek during each of the three years of the pilot study. At completion of the pilot study the District hopes to identify a long-term management strategy and Salmon Creek well operational protocol, that may be based on either creek depth and/or creek flow, that will serve to protect surface water habitat for over summering steelhead and other aquatic resources.
Implementation of the three-year pilot study and interim operations of the District’s Salmon Creek well operations, in accordance with the protocols and criteria outlined above, are intended to protect habitat conditions for steelhead over summering within the lower reaches of Salmon Creek. The District recognizes that a wide variety of other factors influence habitat quality and availability for over summering steelhead within Salmon Creek, many of which are beyond the authority or control of the District.
