Fish Passage Improvement
The RCDTC is involved in multiple large-scale fish passage projects which benefit both winter-run and spring-run juvenile and adult salmonids, including Side Channel Reconnection efforts as well as passage improvements at Antelope and Dye creeks.
Antelope Creek fish passage improvement project
The Antelope Creek Fish Passage Improvement Project addressed a site on Antelope Creek near the Edwards Diversion Dam (EDD) that hindered fish passage. Antelope Creek provides critical habitat for Central Valley spring-run Chinook salmon (SRCS) and steelhead. In this location, key stressors to salmonids included agricultural dams blocking adult immigration, water diversions entraining juveniles, and low flows affecting immigrating adults. This project objective was to address these stressors present in Antelope Creek by:
- Improving downstream passage between the EDD and the Sacramento River
- Reducing the risk of entrainment of fish in the ditches, and
- Improving the accuracy, precision, and timing of irrigation diversions to Los Molinos Mutual Water Company and the Edwards Ranch.
This project provided a new state-of-the-art fish screen with fish bypass to return fish diverted to an irrigation channel back to Antelope Creek. Through these improvements, connectivity between instream habitat above and below the Edwards Diversion Dam was also improved. Such improvement to watershed connectivity will also increase the utilization of anadromous fish habitat throughout the entire Antelope Creek system.
Side Channel Reconnection Projects
The Central Valley Project Improvement Act (CVPIA), section 3406 (b)(13) directs the Department of the Interior (DOI) to develop and implement a continuing program for the purpose of restoring and replenishing, as needed, salmonid spawning gravel lost due to the construction and operation of Central Valley Project dams and other actions that have reduced the availability of spawning gravel and rearing habitat in the Sacramento River from Keswick Dam to Red Bluff Diversion Dam.
The CVPIA Sacramento River Restoration Team is an interagency group with members including Reclamation, The Sacramento River Forum, Department of Water Resources, U.S. Fish and Wildlife Service, California Department of Fish and Wildlife, National Marine Fisheries Service, the Resource Conservation District of Tehama County, and the State Water Resources Control Board. The SRRT was formed to provide technical support in the development of future spawning and rearing habitat restoration projects in the Sacramento River.
So far, the RCDTC is providing construction management on three fish passage improvement projects: The East Sand Slough Side Channel Project, the Rio Vista Side Channel Project, and the Lake, CA Side Channel Restoration Project.
The East Sand Slough Side Channel Project is a rearing habitat restoration project. The purpose of East Sand Slough Side Channel Project is to create a functional side channel at lower flows to provide additional rearing habitat for winter-run juvenile salmonids as well as other species. Currently, adult winter-run Chinook migrate upstream and spawn during the summertime. Once spawning occurs and the eggs have hatched (usually occurs in November), the flows in the Sacramento River are reduced significantly, which can cause stranding issues as well as reducing prime rearing habitat for juveniles.
The Rio Vista Side Channel Project is a rearing habitat restoration and enhancement project. The purpose of the Project is to create a functional lower side channel to provide additional rearing habitat for winter-run juvenile Chinook salmonids as well as other species. Fry emergence occurs during the fall, when typical flows in the Sacramento River are reduced significantly at the end of the irrigation season, which can cause stranding issues as well as reducing prime rearing habitat for juveniles.
The Lake, CA Side Channel Restoration Project was a rearing habitat restoration and enhancement project. The purpose of the Lake California Side Channel Project was to create a functional side channel at lower flows to provide additional rearing habitat for winter-run juvenile salmonids as well as other species. Once spawning occurs and the eggs have hatched, the flows in the Sacramento River are reduced significantly, which can cause stranding issues as well as reducing prime rearing habitat for juveniles. The historical side channel still persists today but has been in need of improvement. Throughout the side channel, fine sediment has accumulated and built up, reducing the capacity of the channel. This project removed sediment at the entrance, allowing more water to enter the side channel, in order to give the channel the opportunity to adjust itself and flush out the fine sediment.
Dye Creek Low Water Crossing Fish Passage Project
The Dye Creek Project is located in Tehama County on the east side of the Sacramento Valley in the Mount Lassen foothills. Currently, a 158 foot-long paved road at Shasta boulevard impedes fish passage at this anadromous watershed. This road crossing in addition to undersized culverts filled with sediment underneath it creates 2-ft to 3-ft head differentials at low flow. This project aims to improve passage conditions for salmonids and make approximately 10 stream miles of non-natal rearing habitat available for winter-run Chinook salmon, spring-run Chinook salmon, and fall-run Chinook salmon that have all been documented just below the barrier (Maslin et al. 1997). The project would also improve passage conditions for adult and juvenile steelhead/rainbow trout that have been documented in the upper watershed (Crain and Moyle 1997) and for adult fall-run Chinook salmon that are assumed to spawn below the barrier.