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| Lower Clear Creek Floodway Rehabilitation Project |
Shasta, California |
Primary Project Type: Instream Restoration
Secondary Type: Riparian Restoration |
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The 15-foot-high by 200-foot-long McCormack-Saeltzer dam was a barrier to upstre... |
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Primary Problem: Channel Alteration, Flow Alteration, Loss of Fish Habitat, Mining
Secondary Problem: Channel Alteration, Mining |
| Main Restoration Action(s): Channel reconstruction, Dam removal, Floodplain reconnection, Flow management, Habitat enhancement, Riparian revegetation |
| Native Fish Focus: Chinook salmon, Steelhead |
Is this project part of a watershed scale restoration? No
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| Project Dates: 1998 to ongoing |
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Initial Monitoring:
Restoration Implementation:
Follow-up Monitoring: |
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Lead Agency:
U.S. Bureau of Land Management
Western Shasta Resource Conservation District
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| Project Partners: |
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The Lower Clear Creek Floodway Rehabilitation Project group is a consortium of 17 public and private sector groups:
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| Project Location:
Clear Creek is a tributary of the Sacramento River situated in the northwestern portion of the upper Sacramento River Basin in California. It begins in the Trinity Mountains and flows approximately 35 miles until it meets the Sacramento River. The Clear Creek watershed is approximately six miles west of Redding in Shasta County. Lower Clear Creek starts at Whiskeytown Dam at river mile 18. Part of lower Clear Creek is within the city limits of Redding, California.
For a map of the project area, click here.
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Project Description:
Historically, lower Clear Creek supported populations of fall-run, late fall-run and, to a lesser extent, spring-run chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss). The latter two populations are presently extirpated from the stream. The cumulative effects of gold mining, gravel extraction, dams, timber harvest, development, and roads in the lower Clear Creek watershed have led to degradation of stream channel and riparian conditions and contributed to the decline of the lower Clear Creek fishery.
In 1848, gold was first discovered in Shasta County. Through the 1940s, placer, hydraulic, and dredge mining significantly altered the lower Clear Creek watershed. The dredging process significantly disturbed floodplains and terraces and removed all riparian and upland vegetation along the corridor as prospectors searched for gold. Piles of dredger tailings were left along the corridor, confining Clear Creek in some locations, and, in other locations, discouraging the natural recovery of riparian and upland plant species.
Through the mid-1980s, commercial instream gravel mining in the lower Clear Creek removed most of the gravel (several hundred thousand cubic yards) within a 1.8-mile reach. An additional 1-mile reach was significantly altered by disposal of dredger tailings. Impacts to channel morphology and salmonid habitat were significant. The bankfull channel was destroyed and floodplains removed, leaving wide, shallow channels and interspersed deep pits. Excessive gravel removal exposed a clay hardpan over much of the channel bottom, directly removing salmonid spawning and fry-rearing habitat. Equally important was the lost channel confinement, allowing both adult and juvenile salmonids to stray into adjacent pits and be stranded.
In 1963, the 282-foot-tall Whiskeytown Dam was built on Clear Creek to impound and divert water through the Spring Creek Tunnel into the Sacramento River above Keswick Dam – which has provided hydroelectric power, flood control, and municipal, industrial and agricultural water supply to the Central Valley. As a result, average annual discharges of Clear Creek below Whiskeytown Reservoir have been reduced by 63 percent from 418 cubic feet per second (cfs) to 152 cfs (McBain and Trush 1997). Flow regulation from the dam essentially eliminated flood conditions that flush silt from gravel, deposit new spawning gravel, facilitate timely juvenile out-migration, attract adult spring-run salmon and steelhead into the stream, and prevent riparian vegetation encroachment. Summer low flows in lower Clear Creek also resulted in lethal temperatures for adult and egg spring-run chinook salmon and sub-lethal temperatures for juvenile steelhead. In 1903, the 15-foot-tall McCormack-Saeltzer Dam was built approximately 10 miles downstream of the Whiskeytown Dam to supply water for gold mining and, later, agriculture. Despite efforts to provide access to 10 miles of upstream spawning habitat using fish ladders and fish tunnels, the dam remained essentially impassable to salmonids. |
Project Goals: The primary goal for the Lower Clear Creek Floodway Rehabilitation Project was to re-establish critical ecological functions, processes, and characteristics – within contemporary regulated-flow and sediment conditions – that best promote recovery and maintenance of resilient, naturally-reproducing salmonid populations and the river’s natural animal and plant communities.
Objectives of the lower Clear Creek restoration actions were to:
- Increase minimum instream flows in lower Clear Creek to improve fish passage, lower water temperatures, and increase abundance of fall chinook spawning and rearing habitat;
- Rehabilitate the channel degraded by historic aggregate extraction in the Mining Reach by reconstructing the bankfull channel and floodplains;
- Restore sediment transport processes, including coarse bedload transport continuity and fine sediment deposition on floodplain surfaces;
- Restore native riparian vegetation on floodplain and terrace surfaces by focusing on species that provide a diverse canopy structure and removing competing exotic species;
- Reduce salmonid stranding and mortality in floodplain gravel extraction pits; and
- Improve fish passage and habitat conditions for the fall-run, late fall-run and spring-run chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss).
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| Project Methods:
Beginning in 1998, multiple agencies who were concerned about Clear Creek formed the Clear Creek Restoration Team (Restoration Team) to plan and implement channel rehabilitation activities in the low-gradient alluvial reach. Their focus was to reverse the impacts of instream gravel mining, dredge mining, and the Whiskeytown Dam. The Restoration Team was comprised of representatives from federal, state, and local agencies, who served as technical advisors on restoration planning, design and monitoring. This project, named the Lower Clear Creek Floodway Rehabilitation Project, restored two degraded reaches of Clear Creek: a 1.5-mile reach extensively mined for aggregate (Project Reach), and a 1.0-mile reach containing dredger tailings to be used as borrow materials at the Project Reach. In addition, two off-channel sites were restored as wetland/riparian habitat following removal of borrow materials for the Project Reach. Other significant restoration efforts included increasing minimum instream flows, removing Saeltzer Dam, and introducing spawning gravels into lower Clear Creek.
For more information on restoration actions performed on lower Clear Creek, click here.
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Clear Creek tracer rock painting operation at Phase 3A.... |
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D50 and D84 tracer rock-set on left bank gravel-lobe at Reading Bar XS 419+00.... |
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| Monitoring Data and Collection
Methods: Extensive monitoring has been done to assess the effectiveness of restoration actions in restoring critical ecological functions, processes and characteristics in lower Clear Creek and in improving habitat conditions for anadromous salmonids native to this region.
For details on these monitoring efforts, click on the link below:
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| Was this project effective
and how was this determined? Through a unique multi-agency partnership and the commitment of over 21 million dollars to date from multiple agencies and programs, lower Clear Creek and its salmonid populations are being restored. Increased stream flows have been the primary reason. There has been a five-fold increase in fall chinook spawning escapements in Clear Creek from 1995 to 2002 over the baseline period of 1967 to 1991. The flows improved fish passage into Clear Creek, improved water temperatures during spawning and rearing periods, increased the amount of spawning and rearing habitat, and contributed to record numbers of fall chinook salmon spawning in Clear Creek.
For more information, click here.
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Restoration Grove was replanted with native trees and shrubs, creating a patch o... |
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Restoration Grove during spring flooding with the floodplain functioning as desi... |
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| Confounding Effects/Additional
Information: The channel designs assume a future channel forming flood of 3,000 cfs; however, the designers were concerned that 3,000 cfs is insufficient to maintain the integrity of the rehabilitation project (i.e., prevent riparian encroachment) and satisfy important ecological goals (channel migration, bed mobility). The U.S. Bureau of Reclamation is presently evaluating options for increasing the magnitude of future channel-forming flows, which will significantly improve project performance. |
| Project
Specs (all specs are estimates): |
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Overall Estimated Cost:
21,000,000
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| For more information on this project
contact: |
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Gary Diridoni, Wildlife Biologist, Bureau of Land Management, Redding Office, Email: gary_diridoni@ca.blm.gov
Leslie Bryan, Clear Creek Watershed Coordinator , Western Shasta Resource Conservation District, Email: leslie@westernshastarcd.org
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| This information
was collected by: Kristin Keith |
| Project last updated on: 3/22/2007 |
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