The Lake County Watershed Councils and private landowners with funding provided by the Oregon Watershed Enhancement Board, U.S. Fish and Wildlife Service, retained River Design Group, Inc. (RDG) to complete a reconnaissance and project prioritization plan for over 20 miles of Crooked Creek, a tributary to the Chewaucan River near Valley Falls, Oregon. RDG completed two phases of project implementation including the Simms Diversion Fish Passage Project. The Simms Project included construction of a rock ramp and weir modifications to improve fish passage and diversion efficiency of a concrete diversion weir on lower Crooked Creek.
Due to the height of the existing weir, downstream channel scour, and lack of a fishway, the Simms weir had been a fish passage barrier on lower Crooked Creek for over 50 years. The project goal was to reconnect lower Crooked Creek to restore passage for adfluvial Chewaucan redband trout life-history.
The diversion weir invert was raised by retrofitting the existing weir with a wall extension. The extension established the necessary head to divert water into the adjacent irrigation pipeline. The fixed weir elevation also allowed for building a rock ramp that tied to the top of the weir, providing elevation certainty for the fish passage solution.
RDG worked with a local contractor to complete the construction in 2016. The rock ramp raised the channel bed elevation to compensate for the raised weir elevation. Locally sourced juniper, rock, and willow clump transplants and cuttings were installed as part of the project.