Kings River Water Association - Kings River Conservation District - California Department of Fish and Game
Fishery habitat enhancement is at the heart of the innovative Kings River Fisheries Management Program. It is also what the Thorburn Spawning Gravel Channel is all about. The Thorburn project was completed in March 2000 and is the first Kings River Fisheries Management Program habitat improvement project to become reality. Supplied with its own regulated and dedicated flow of water, the Thorburn Spawning Gravel Project has transformed an unused, overgrowth-choked channel into a water course in which juvenile trout can spawn and safely grow, and other fish can find shelter from the main river’s often high flows and swift currents. It also promises important research and educational benefits. Named for property owners who graciously provided a conservation easement to make the project possible, the channel is managed by the Kings River Fisheries Management Program’s partnering agencies: the Kings River Conservation District, Kings River Water Association and California Department of Fish and Game.
Where the Channel Is Located
The Thorburn Spawning Gravel Channel, approximately one-half mile in length, parallels Piedra Road near Elwood Road, a short distance south of Winton Park in the Piedra area, about 20 miles east of Fresno. The channel is easily viewed from the road.
The channel makes use of what was originally developed decades ago as a recreational fishing and camping area. Except for high flows and seepage from the nearby river, the channel had been unused since the early 1960s. Its location is ideal. The channel leaves the main Kings (on the river’s left, or southeast, bank) immediately downstream from Fresno County’s Winton Park and rejoins the river through a pool that rises or falls based upon the rivers stage.
Purpose of the Project
Thanks to the project, habitat has been created to afford a safe haven in which young fish can safely grow. At the same time, the Thorburn Spawning Gravel Channel provides related riparian environmental benefits as well as research and educational opportunities.
Development and Construction
Administered by the Kings River Conservation District, the project’s development and construction took place from the fall of 1999, when clearing of unwanted vegetation began, through March 2000 when the channel was excavated and its headgate was installed. A feasibility study, completed by the KRCD prior to enactment of the Kings River Fisheries Management Program, determined that the channel would be an effective spawning site for trout.
Channel Design and Features
The Thorburn Spawning Gravel Channel begins with a headgate structure, constructed as part of the project that regulates the flow of water through the channel to levels determined by biologists to be appropriate. Channel water flows are far gentler and slower than in the main river. Meanders were constructed while the channel was being excavated to extend the length of the channel’s habitat benefit. Boulders, gravel and woody debris have been placed throughout the channel as part of an attempt to mimic natural stream conditions and provide cover and shelter to juvenile trout. Mature trees were retained but all non-native vegetation (notably what had been nearly impenetrable stands of arundo, or Afalse bamboo) was removed. The channel’s outflow blends naturally into the river from a calm pond, in which young fish can safely grow. Trout can enter and exit the spawning channel at the lower end. It will be available for use all year.
Future Channel Development
Extensive planting of new riparian vegetation is planned along the channel, utilizing oak, cottonwood and willow trees, so that the Thorburn Spawning Gravel Channel will become part of Fresno County’s natural lower foothill environment.
The channel was constructed under a $129,200 contract administered for the Kings River Fisheries Management Program by the Kings River Conservation District. Total project cost was $222,000. The cost is being shared by the KRCD and Kings River Water Association, with the welcomed assistance of a $116,000 environmental enhancement grant received from Caltrans, the state’s transportation agency.
To Learn More
For additional information, please telephone the Kings River Water Association, 266-0767; the Kings River Conservation District, 237-5567; or the California Department of Fish and Game, 243-4005.