5/2007 by Marcia Armstrong, Siskiyou County Supervisor

The problem is: during late summer and early fall, low water levels in some streams limit the amount of rearing and spawning habitat available for anadromous fish, (coho and Chinook salmon and steelhead trout.) An answer is: to raise water levels to accomplish specific flow targets that will increase habitat when needed for critical stages of fish life. The approach is: to solicit voluntary temporary dedication of water to the stream in exchange for a fair compensation at least equal to the value of the water had it been applied to the land.

We now understand much better how fish use the Scott River watershed during their different life stages. For instance, we know that the fish need
25-30 c.f.s. (cubic feet per second) of fall flows at the USGS gage to travel up the canyon to spawning areas in the valley. We know that a total flow of around 17 c.f.s. is needed at French Creek and at Shackleford Creek for connectivity with the mainstem Scott River. In most cases, it takes anywhere from and additional
.5-2 c.f.s. in specific reaches from July to the end of the irrigation season in October, (or when the rains come,) to meet targeted flows for rearing and spawning.

Scott River water use rights are governed by a formal adjudication (Siskiyou County Superior Court) establishing volumes and priorities of surface water and associated groundwater use in various reaches throughout the system. A legal analysis has been completed for the Trust concept working with the adjudication to create a decision tree which asks such questions as: Does the stream provide habitat? Are there sufficient natural flows to meet targets? Are there willing participants? Can they demonstrate the recent use of water? Are there concerns that non-participants can use any water dedicated under their adjudicated right? These questions will help determine the best candidates for the program.

Although some of the adjudicated rights are riparian and cannot be lost from non-use, many are early appropriative rights that date back as far as the gold rush era. Such rights can be lost from nonuse - claimed by another diverter after five years (statute of limitations.) Since it has been almost impossible to get a permanent dedication of water through the legal process, the Water Trust proposes to use "forbearance contracts" that run from one to three years. Most will take the form of a split season lease, allowing the participant to soak with flood irrigation in the plentiful months from April through June, with cessation of all irrigation as of July or after the second pasture cutting.
(Alfalfa and pasture are perennial crops with seven and twenty year productivity spans respectively. This may have some long term impacts on the productivity of the crop.) Stockwater diversions run all year round. Ranchers could find alternative sources of water during critical periods under forbearance agreements.

An economic study is being completed by WestWater Research on the economic valuation of agriculture water in Scott Valley for crops and livestock. The study will also examine appropriate funding sources from a special district to grants or an endowment fund that will provide sustainable funding for the Trust. For instance, it is estimate that a $2 million endowment would yield approximately $80-100,000 in interest. This might secure an additional 7-9 c.f.s. in the tributaries from forebearance agreements on irrigation of marginal pasture and stockwater diversions. (The cost of forbearance on alfalfa crops would be considerably more as a higher valued crop.) Single year contracts would vary according to the type of water year and consequential value of that year's water to the fish. Multiple year forbearance agreements would most likely be based on an average water year.

The sooner a source of funding steps forward, the sooner this fair win/win solution can be implemented.
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Recently, the Scott River Watershed Council (SRWC) gave an update on its progress in developing a water balance for the Scott River system. A water balance takes into account inputs from precipitation - rain and snow. It examines how that materializes into surface water flows, groundwater storage and snowpack storage to be delivered later though snowmelt. It also looks at outputs - diversions of surface water and pumping of groundwater and how that affects hydrology/the water system. It creates a model over space and time to help us understand how the entire system functions.

The water balance will be helpful in improving water management practices, implementing the water leasing or Water Trust concept, developing a dry year water plan and in identifying stream reaches with the highest potential for habitat restoration.

In 1998, the Siskiyou Resource Conservation District (RCD) began to compile all available water data for the system. This included flow readings from 1941 to present at the USGS gauge below Fort Jones. In 2002, the California Department of Water Resources and the U.S. Fish and Wildlife Service installed additional river flow gauges at: East Fork Scott, South Fork Scott, McConaughy, Sugar Creek, Shackleford , Mill, Kidder, French and Etna Creeks. In addition to two existing U.S. Forest Service gauges, in
2003 the RCD installed 10 rain gauges.

From 2003-2005, a rough spreadsheet model of the hydrology of the system or water balance was developed by Mike Deas Ph.D, which continues to be refined as more detail is known.

In 2005, a draft run-off forecast model was created. This model has taken into account all snowpack and rainfall data for the past 50 years.

(See DWR Bulletin 120.) The run-off forecast considers precipitation and groundwater conditions of the previous year, variations in precipitation over time and space throughout the system, and changes in land and water use patterns. The model predicts the volume of water that will flow through the Fort Jones gauge from April 1-October 1 based on April 1 snowpack and precipitation conditions. Refinements are underway to forecast at the subwatershed level.

A water year type index has also been created categorizing years as wet, dry or normal and looking at the combined effects of a two year span. Keeping in mind that the forecast is limited to conditions as they were prior to April 1 of the current year, this information can be used to describe the water supply conditions anticipated in a given year.

DWR has periodically taken measurements from 3 wells over a 50 year period. In 2006 an additional voluntary groundwater study piece was added. This study selected 33 wells located in a grid over the central portion of Scott Valley to measure the static water level of each well throughout the year. It was determined from the first year's measurements that all wells do not react similarly. During the year, wells in the main part of the valley near the river followed the river's hydrograph - dropping 3-4 feet during the summer. They began to inch up in October after the first frost, but did not really begin to recover until December. A few wells in other areas did not see the same recharge. It is anticipated that at least 10 years or more of readings will need to be taken to capture most of the water year and runoff variations so that we have a better idea of how groundwater responds to various water conditions.