Owner: Emmerson Investments
Location: Shasta Valley, California
Funding Source: Pacific States Marine Fisheries Commission administered by California Department of Fish and Game
Completion Date: 2011
Shasta Springs Ranch (Ranch) consists of 10,325 contiguous acres of land in the Shasta Valley, roughly 10 miles north of Weed and 16 miles south of Yreka. It is owned by Emmerson Investments and operated for beef cattle production. The Shasta River and one of its principal tributaries, Parks Creek, course through the Ranch. Both streams and related springs serve as water supply sources for pasture irrigation on the Ranch. Both streams also provide habitat for certain species of salmonids classified as threatened or endangered under state and federal protection laws. Diversions of water cause depletion of streamflow and result in irrigation return flows to the streams that may at times degrade water quality. Both of these processes can adversely affect salmonid habitat and survival.
In early 2009, Emmerson Investments and the California Department of Fish and Game (DFG) agreed to conduct a cooperative investigation into opportunities to improve irrigation practices on the Ranch in a manner that would improve conditions for fish but also would allow sustained operation for beef production. Davids Engineering was selected as the technical contractor to conduct the investigation. Due to the lack of historical records, a major component of the investigation was to design and implement a program on a fast-track basis to measure streamflow, spring flow, irrigation diversions and groundwater levels.
Davids Engineering began by designing a water balance structure that would allow characterization of stream hydrology and irrigation system performance. The streams were divided into six analysis reaches defined primarily by points of diversion and return flows. Associated with the six stream reaches were 10 groups of irrigated fields comprising 2,398 irrigated acres and 503 sub-irrigated acres, or 2,901 acres in all. Field inspections were made of all existing irrigation diversion measurement structures, spring sources, groundwater wells and potential river gauging stations.
For each of the 24 total sites, different measurement options were identified and evaluated with respect potential measurement accuracy and cost, leading to a recommended measurement methodology for each one. Sharp-crested weirs, rated sections, orifice gates, pipe flow meters and other methods were used. Davids Engineering then specified, procured, installed and commissioned the monitoring equipment for each site, including installation of data loggers to record data continuously. Remote monitoring and data acquisition via SCADA was considered but found to be cost-prohibitive given the relatively short (20-month) monitoring period.
From February 2009 through October 2010, Davids Engineering conducted regular site visits to download data, maintain sites and conduct independent flow measurements to establish discharge coefficients and to maintain rated sections in streams. A SonTek FlowTracker acoustic Doppler velocimeter was used for most of the independent flow measurements. Given the remoteness of the sites and rugged field conditions, all site visits were made by 4 wheel drive quads.
All data was quality controlled, gap filled where necessary and loaded into a Microsoft Access database. The data was then used by Davids Engineering analysts to calculate stream reach and irrigated area water balances, which served as the technical foundation for formulating alternative water management improvements.