Contra Costa County Flood Control and Water Conservation District
Contra Costa County
Public or private land?
Christie Road crossing of Rodeo Creek about a mile south of Franklin Canyon Golf Course and just upstream of Fernandez Ranch, near Rodeo, CA
The entire Rodeo Creek watershed is negatively impacted by the large sediment load caused by channel instability. For many decades, a large headcut has been moving upstream dramatically changing the elevation of the channel thalweg. Sheet piles are one way to create a stabilized drop at Christie Road and stop the further unravelling of the creek.
This project will install a grade control structure at the Christy Road crossing of Rodeo Creek to stop upward movement of large head cut that is destabilizing the creek and introducing large amounts of sediment into the watershed. This will help stabilize the quickly unraveling creek and also eventually lessen the volume of sediment needing to be removed in the lower reaches of Rodeo Creek.
Drinking Water Supply
Water Quality Improvement
Habitat Protection and Restoration
The project stabilizes the creek, preserving habitat in the adjacent area. Without the project, the creek will continue to severely deepen and widen, consuming the creek bed and banks and washing the lot downstream. This project will reduce the large sediment loading, leading to water quality improvements. A stable creek is also better able to provide flood protection.
Seeking partnership with stakeholders, such as utility owners (Railroad is adjacent, and gas pipelines cross nearby), and adjacent landowners such as Muir Heritage Land Trust. Friends of Rodeo Creek and local RCD would be good partners as well.
Possibly. The project will likely be funded by a combination of sources, including local road maintenance funds.
One could argue that the drop structure leads to channel stability and a better functioning creek.
Part 2 - Detail
Construct a row of sheet piles and associated bank stabilization and revegetation in Rodeo Creek to stop the upward migration of a large, destabilizing head cut in the creek. The sheet piles can be located downstream closer to current location of the head cut, but the more logical location for construction and maintenance is at the Christy Road crossing of the creek, located about 500 feet upstream of the head cut. Here, the sheet piles can be installed below the existing grade and would then be available to counteract the upward migration of the head cut.
Full stabilization of Rodeo Creek is unlikely and impractical. But some tree planting efforts would be included to partially counteract the mature trees that have already been undermined and collapsed into the quickly deepening creek.
Rodeo Creek Stabilization Study, prepared for Kinder Morgan by URS Corporation. May 2004
Rodeo Creek Restoration Plan, prepared for Muir Heritage Land Trust by Restroation Design Group, 2009
San Pablo Bay
Rodeo Creek has long exhibited signs of severe erosion and channel degradation in the upper portion of the watershed. This has forced relocation of underground utilities crossing the creek and a large retaining wall to hold up the adjacent roadway and railroad. Survey monitoring of the the channel indicate that the channel invert has dropped over 9 feet in 14 years. This is not normal erosion.
Portions of the creek below the headcut are over 40 feet deep. At the Christy Road crossing, with roughly the same tributary area in the creek, Rodeo Creek is approximately 15 feet deep. The headcut is moving upstream and true creek stability is elusive.
If no grade control is introduced, eventually Christy Road (a County-maintained roadway) will be washed out and a much large bridge would be needed to span the expanded, unstable creek. Creek bed and banks (and mature riparian vegetation) will continue to be lost.
To head off this possibility, burried driven sheet piles should be installed just downstream of the existing road crossing.
i. Water Supply (conservation, recycled water, groundwater recharge, surface storage, etc.)
ii. Water Quality
...Stabilizing the creek will greatly reduce the sediment load that is being dumped into the creek.
iii. Flood and Stormwater Management
...Stabilizing the creek upstream means less sediment accumulating in populated areas downstream. This leaves more capacity in the creek for flood flows.
iv. Resource Stewardship (watershed management, habitat protection and restoration, recreation, open space, etc.)
...The stabilization of Rodeo Creek prevents the destruction of riparian vegetation and habitat.
Increases Water Supply Reliability
Advances/ Expands Conjunctive Management of Multiple Water Supply Sources
Increases Water Use and/or Reuse Efficiency
Provides Additional Water Supply
Promotes Water Quality Protection
Reduces Water Demand
Advances/Expands Water Recycling
Promotes Urban Runoff Reuse
Addresses Sea Level Rise
Addresses other Anticipated Climate Change Impact (e.g. through water management system modifications)
Improves Flood Control (e.g. through wetlands restoration, management, protection)