Glenn-Colusa Irrigation District


The Glenn-Colusa Irrigation District (GCID) appropriative water rights begin on the Sacramento River with an 1883 filing posted on a tree by Will S. Green, surveyor, newspaperman, public official, and pioneer irrigator.  His first claim was for 500,000 miner’s inches under 4 inches of pressure and was one of the earliest and largest water rights on the Sacramento River.

GCID was organized in 1920, after several private companies failed financially, and a group of landowners reorganized and refinanced the irrigation district, retaining claim to Green’s historic water right. The disastrous rice crop failure of 1920–21 nearly destroyed the district at its inception, and the “great depression” took a further toll, making it necessary for the district to refinance in the 1930s.  Additionally, the United States purchased lands within GCID during this period which would later become three federal refuges totaling approximately 20,000 acres.

Today, after surviving many challenges, GCID is the largest district in the Sacramento Valley.  Located approximately eighty miles north of Sacramento, California, the district boundaries cover approximately 175,000 acres; of which 153,000 acres are deeded property and 138,800 are irrigable.  There are 1,076 landowners in the District and an additional 300 tenant water users.  There are an additional 5,000 acres of private habitat land, and winter water supplied by GCID to thousands of acres of rice land provides valuable habitat for migrating waterfowl during the winter months.

GCID’s main pump station, its only diversion from the Sacramento River, is located near Hamilton City.  The District’s 65-mile long Main Canal conveys water into a complex system of nearly 1,000 miles of canals, laterals and drains, much of it constructed in the early 1900s. The District headquarters are located in Willows, the county seat of Glenn County, approximately 90 miles north of Sacramento on Interstate 5.

A five-member board of directors, who represent five subdivisions within the District, governs the District.  The annual budget is $15 million. GCID’s mission is to provide reliable, affordable water supplies to its landowners and water users, while ensuring the environmental and economic viability of the region.

Water Supply
From its first diversions until 1964, GCID relied upon its historic water rights and adequate water supply from the Sacramento River hydrologic system which receives rainfall and snowmelt from a 27,246 square mile watershed with average runoff of 22,389,000 acre-feet, providing nearly one-third of the state’s total natural runoff.  In 1964, after nearly two decades of negotiations with the United States, GCID along with other Sacramento River water rights diverters entered into “Settlement Water Contracts” with the Bureau of Reclamation (Bureau).  These Settlement Contracts were necessary at that time to allow the Bureau to construct, operate, and divert water for the newly constructed Central Valley Project.  The contract provided GCID with water supply for the months of April through October for 720,000 acre-feet of base supply, and 105,000 acre-feet of Central Valley Project water that is purchased during the months of July and August.  During a designated critical year when natural inflow to Shasta Reservoir is less than 3.2 million acre-feet, GCID’s total supply is reduced by 25%, to a total of 618,000 acre-feet.

Additionally, the District has rights under a State Water Resources Control Board (SWRCB) permit to “winter water” from November 1 through March 31 at a 1,200 cubic feet per second (cfs) diversion rate.  This water supply is used for rice straw decomposition and waterfowl habitat.  The permit provides 150,000 acre-feet for rice straw decomposition and 32,900 acre-feet for crop consumption.

Groundwater can be used to supplement GCID’s supplies, with 5,000 acre-feet available from District wells, and approximately 45,000 acre-feet from privately owned landowner wells.


Contract Renewal
In 2004, GCID and other Sacramento River Settlement Contractors that had negotiated 40-year contracts with the Bureau of Reclamation in 1964 successfully negotiated a 40-year renewal of contracts with the same quantities and critical year terms.  However, shortly after the renewal of these contracts, several environmental groups challenged a U.S. Fish and Wildlife Biological Opinion which put at risk the validity of these contracts.  Five years later, in April, 2009, Judge Oliver W. Wanger of the United States District Court, Eastern District of California, issued a significant decision and ruled that the federal government and Sacramento River Settlement Contractors reached agreement in the early 1960s “on long-term contracts to continue for a 40-year term and renewal thereafter, for fixed contractually defined quantities (of water) . . .” that predates the Endangered Species Act (ESA) and the Central Valley Project.

Fish Screen Improvement Project and Monitoring
In 1993, GCID in coordination with the US Bureau of Reclamation and the Corps of Engineers, began an $80 million GCID Fish Screen Improvement Project that included planning, design, environmental planning, oxbow channel improvements, forebay enlargement, construction of a 620-foot extension to the existing 480-foot flat plate fish screen, construction of a gradient restoration facility in the Sacramento River, 29 acres of mitigation plantings, and an extensive evaluation and monitoring program.

The project was necessary in order for GCID to continue its diversions from the Sacramento River without affecting winter run Chinook salmon.  However, the facility was also designed to ensure other salmon run species and sturgeon would be protected.  Following completion of construction in 2001, GCID conducted a five-year evaluation of the screen project to ensure it performed according to specifications and that fish were not being “taken” as a result of operations.  The evaluation and monitoring program concluded in 2007-2008 and demonstrated that fish are safely passing GCID’s Sacramento River diversion facility.  GCID is currently working with Reclamation and the Corps to close out the project and have GCID perform all operations and maintenance obligations on the facilities.

Refuge Conveyance Project
GCID was selected as the preferred delivery alternative to convey a continuous, year-round water supply to three National Wildlife Refuges in the Sacramento Valley, as part of a 50-year agreement between the Bureau and GCID.  The $15 million project that consisted of the modification of 100 minor structures and seven major structures, including three large siphons, provides the District with the ability to deliver water to the refuges and the wildlife habitat on a year-round basis.

Development of a Water Resource Plan
Last year, the GCID Board of Directors approved the implementation of a Water Resource Plan designed to assess major issues that impact the district now and in the future.  The Plan scope was initially comprehensive and included issues such as water supply, water transfers, operation and maintenance, capital improvements, communications, organization/personnel, political governance and financial planning.  However, the Board was concerned that the scope was too large, and potentially expensive.  Ultimately, the Board, with management input, decided to break the Plan into individual components with priority given to the most pressing and critical issues such as water supply needs and water transfers/exchanges.  As each issue area is addressed, another issue area is then initiated with the process culminating into a final Plan.


Water Transfers
In recent years, below normal water years, in addition to the rededication of water from agriculture and urban uses back to the environment has resulted in water supply shortages throughout the State.  While discussions and planning  are occurring for longer term solutions such as additional storage and improved Delta conveyance, short term “gap” actions are necessary to meet existing demands.  GCID has viewed water transfers as a short term action to help other regions meet shortages, while at the same time protecting its underlying water rights.  For Northern California, serious concerns exist that if water is not transferred to meet needs, political pressure will be exerted to overhaul the existing water rights system that could result in even more water being rededicated to other purposes, and without compensation.

In 2009, GCID along with other Sacramento valley (SV) agencies participated in the Department of Water Resources (DWR) 2009 Drought Water Bank (“2009 Bank”) which was a comprehensive water transfer effort to move water from willing sellers to willing buyers.  With meetings beginning in August 2008 and continuing into early May 2009, many of the SV Sellers were unable to participate in the 2009 Bank, as structured and proposed for implementation by DWR.  The SV Sellers communicated to DWR their concerns regarding the 2009 Bank during the dozens of meetings and discussions that they participated in with DWR and Reclamation staff.  The primary issues of concern were: the purchase price for land fallowing was set too low to compete with the commodity prices, groundwater wells with diesel pumps were exempted if Reclamation approval was required, increased mitigation and monitoring requirements for groundwater substitution transfers, conservation measures imposed by the United States Fish & Wildlife Service and the USBR for the giant garter snake (GGS) were obstructive,  limited conveyance capacity due to Delta export limitations, and lack of a comprehensive approach to resolve the above issues.

Bay Delta Conservation Plan
As a Habitat Conservation Plan/Natural Community Conservation Plan, under federal and state law respectively, the purpose of the Bay Delta Conservation Plan (BDCP) is to provide for the conservation of threatened and endangered fish species in the Delta and improve the reliability of the water supply system within a stable regulatory framework. When adopted and approved by the federal and state fishery agencies, it will result in the issuance of long-term permits for those activities that support water supply and power generation, such as water conveyance and facility maintenance and improvements.

As the BDCP has advanced in its planning process, the activities have been primarily limited to the legal Delta.  However, BDCP discussions now are focusing on upstream operations and diversions, which are outside the scope and physical boundaries of the BDCP.  GCID’s concern, as a major diverter on the Sacramento River, is to what extent would changes to system operations proposed by the BDCP impact or effect our diversions and beneficial uses of water.  GCID is also not a signatory stakeholder to the BDCP so as actions continue to be proposed outside of the BDCP, GCID is beginning efforts to engage in these discussions in order to protect its existing water supply.

Groundwater Investigations
GCID and the Natural Heritage Institute (NHI), a solution based environmental organization, are conducting a Surface-Groundwater Reoperation Study to examine whether and how operation of deep aquifers in the Sacramento Valley could be integrated with operation of existing surface water reservoirs (Oroville, Shasta, or Orland Project reservoirs on Stony Creek) to produce additional firm water supplies.  New supplies could be used to satisfy unmet in-Valley irrigation demands, contribute to meeting environmental flow targets particularly in the Sacramento and Feather Rivers, or produce additional water for statewide (Bay-Delta) supply if possible.  The Project planning area encompasses the entire Sacramento River basin, although primary attention focuses on areas of the northern Sacramento Valley where, based on best available information, the Lower Tuscan formation and related deep aquifers are thought to exist (along with the presence of other features essential to conjunctive management). This includes portions of Butte, Colusa, Glenn and Tehama counties.

The scope of the planning effort includes technical analyses with emphasis on surface water and groundwater modeling to define how conjunctive operations might work and what their impacts could be.  Additionally, once the new facilities needed to enable conjunctive operations are defined, engineering analyses and costs estimates will be prepared so that economic evaluation of prospective projects can be assessed.  Additionally, operation scenarios will include integration with proposed flow standards, facilities, and storage as being considered in the Bay-Delta Conservation Plan (BDCP) process.




Post Office Box 150, Willows, California 95988      344 East Laurel Street, Willows, California 95988      Phone: 530.934.8881     Fax: 530.934.3287     Email:


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