Cache Creek Dam

Cache Creek Dam
Name	Cache Creek Dam
Location	Yolo County, California
Country	United States
Status	Operational
Owner	Yolo County Flood Control and Water Conservation District
Dam type	Earthfill
Dam height	40 ft
Dam length	1,000 ft
Reservoir	Cache Creek Reservoir (Clear Lake region)
Capacity total	~5,000 acre-feet
Opening	20th century

Cache Creek Dam Cache Creek Dam is an earthfill flood-control structure on Cache Creek in Yolo County, California, serving water supply, flood management, and recreation functions for nearby communities. The facility is operated by the Yolo County Flood Control and Water Conservation District and coordinates with regional agencies for reservoir regulation, habitat protection, and emergency response. It interfaces with state water projects, regional ecosystems, and recreational networks across the Sacramento Valley and the Clear Lake watershed.

Introduction

Cache Creek Dam sits on a tributary linking the Clear Lake watershed to the Sacramento River basin, positioned within the Sacramento Valley near Woodland and Davis. The dam functions as part of a network including the Yolo Bypass and interacts with infrastructure managed by the California Department of Water Resources, the United States Army Corps of Engineers, and local water districts. Its role touches floodplain management, agricultural irrigation distribution to orchards and vineyards in the Capay Valley, and sediment transport affecting downstream channels like the Sacramento River.

History and Construction

Construction of Cache Creek Dam followed regional flood events and agricultural expansion in the early to mid-20th century, reflecting influences from projects such as the Central Valley flood control initiatives and floodplain reclamation efforts tied to post‑Dust Bowl policies. Planning involved coordination among the Yolo County Flood Control and Water Conservation District, state agencies, and federal partners including the United States Bureau of Reclamation on water rights and diversion frameworks. The structure was sited to moderate runoff from Clear Lake and upstream tributaries after comparative studies that considered alternatives like levee systems used in the Yolo Bypass and modifications modeled on projects executed by the Army Corps of Engineers. Its incremental upgrades responded to regulatory developments from the California State Water Resources Control Board and environmental rulings influenced by cases involving aquatic habitat protections overseen by agencies such as the United States Fish and Wildlife Service.

Design and Specifications

The dam is an earthen embankment with a concrete control structure that houses radial gates and spillway works similar in concept to those found at smaller diversion facilities across California. Key specifications include embankment height and crest length engineered to retain a reservoir with storage capacity sized for seasonal runoff and irrigation demands. Instrumentation for seepage, piezometers, and slope stability monitoring aligns with standards promulgated by the Federal Emergency Management Agency and California Division of Safety of Dams. Hydromechanical components coordinate with gauging networks maintained by the United States Geological Survey and telemetry systems used by local water districts to manage releases for downstream users and the Yolo Bypass complex.

Hydrology and Reservoir Operations

Reservoir operations at the site balance flood attenuation, seasonal irrigation releases for growers in Yolo and adjacent counties, and baseflow augmentation to support migratory fish pathways linked to the Sacramento River. The reservoir receives inflow from Clear Lake tributaries and upstream creeks, with outflow regulated through spillways and gates to meet requirements under state water rights administered by the State Water Resources Control Board and environmental flow prescriptions arising from consultation with the National Marine Fisheries Service. Hydrologic modeling for operations incorporates precipitation records from the National Oceanic and Atmospheric Administration, snowpack and runoff projections used by the California Department of Water Resources, and flood-frequency analyses consistent with FEMA mapping for the Yolo Bypass and Sacramento River floodplain.

Environmental and Ecological Impact

The dam alters sediment transport, thermal regimes, and connectivity for native anadromous species with historic runs of salmonids that move between Clear Lake tributaries and the Sacramento–San Joaquin Delta. Mitigation measures have included managed flows, fish passage planning, and habitat restoration coordinated with the California Department of Fish and Wildlife, the United States Fish and Wildlife Service, and conservation groups active in the Capay and Putah Creek corridors. Water quality concerns such as nutrient loading, mercury methylation inherited from legacy mining upstream in the watershed, and algal blooms in Clear Lake factor into management alongside endangered species considerations under the Endangered Species Act and state-level species listings enforced by conservation agencies.

Recreational Use and Public Access

The reservoir and surrounding lands support boating, angling for bass and trout species, birdwatching tied to migratory routes used by species cataloged by Audubon chapters, and trails that connect to regional parks and open-space preserves. Access is overseen by Yolo County and coordinated with state parks or recreation entities when adjacent lands fall under their purview. Recreational management must reconcile public use with habitat protections enforced through permits and stewardship actions guided by agencies such as the California Department of Parks and Recreation and local conservancies.

Safety, Maintenance, and Incidents

Routine maintenance, emergency action planning, and seismic risk assessments conform to protocols from the California Division of Safety of Dams, FEMA floodplain guidance, and engineering standards advanced by the United States Army Corps of Engineers and professional societies. Past incidents and responses have involved coordinated notifications among the Yolo County Office of Emergency Services, the State Office of Emergency Services, and local municipalities like Woodland and Davis when high‑flow events have tested spillway capacity or required controlled releases. Upgrades to instrumentation, gate refurbishment, and sediment management are part of ongoing asset management to reduce downstream flood risk and maintain compliance with state inspections and federal grant conditions.

Category:Dams in California