Glenn-Colusa Irrigation District

By Sarah May 26, 2021

Serving our lands and environment sustainably through partnership driven cooperation for over 100 years.



Glenn-Colusa Irrigation District (GCID or District) is the largest water district in the Sacramento Valley with a long history of serving the agricultural community while also maintaining critical wildlife habitat. GCID is located west of the Sacramento River spanning across Glenn and Colusa Counties, from approximately Hamilton City, CA to Williams, CA.

Key Agency Facts

GCID’s water rights were established in 1883, one of the earliest and largest water rights on the Sacramento River; the District was formally organized in 1920. As a senior water rights holder on the River, GCID is a member of the Sacramento River Settlement Contractors with Federal water rights preceding 1914. As a leader in the Sacramento Valley, GCID works with partners across beneficial uses to leverage the stability of the SRSC water contracts to serve landowners, water users, and the agricultural community while actively supporting and improving watershed health. The District is focused on continuing to deliver a sustainable, reliable, secure, and economic water supply to its landowners by proactively responding to the ever-changing water landscape.

Service Area Details

GCID’s service area covers approximately 175,000 acres, of which approximately 140,000 acres are irrigable.  There are an additional 5,000 acres of private habitat land and 25,000 acres of protected wildlife refuge. Located within the Pacific Flyway, the 65-mile long GCID Main Canal and nearly 1,000 miles of laterals and drains create a system that actively supports the District’s main crops of rice, orchards, tomatoes, and row crops. Rice lands, GCID’s predominant crop, provide valuable habitat for migrating waterfowl and shorebirds.

How long has GCID been an investor in Sites Reservoir?

GCID has been a proponent of the Sites Reservoir Project for over 20 years and was a founding member of the Sites Project Joint Power Authority formed in 2010. The Sites JPA is the proponent and facilitator for the Sites Reservoir. GCID is not only a project investor, but also a Facility Partner since the District will play a large role in filling the reservoir once constructed.

Why did GCID decide to invest in Sites Reservoir?

Glenn-Colusa Irrigation District considers Sites Reservoir to be an essential component to California’s long-term water resources strategy. Sites has been identified by both the State and the Federal government as an important component of integrated water management in the Sacramento Valley that could advance long-term objectives of improved water management and restored ecological health for the Delta and the Sacramento River watershed. Sites would provide a new source of water to Sacramento Valley farms and families and relieve pressure on groundwater basins, particularly during drought conditions.

What makes GCID unique?

GCID has a deep commitment to sustainable practices – both in managing the water supply, as well as preserving and protecting the environment and wildlife in the region. The District has completed numerous projects to ensure minimal impact of water diversion on fish and wildlife, as well as deliver water to maintain critical wildlife habitat. GCID and its partners in the region have been leaders in efforts to work with solution-oriented environmental organizations to manage water along the Sacramento River for the benefit of salmon, birds that use the Pacific Flyway, and endangered terrestrial species like the Giant Garter Snake.  GCID is committed to improved watershed health while meeting agricultural needs through demonstrated vertical engagement: innovation, collaboration, and implementation.

For more information

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