Document Actions
Lower Walnut Creek Restoration
| Contact Person | |
|---|---|
| Web | link |
| Lead Organizations | |
| Investigators | |
| Participating Organizations | |
| Start Date | 2003/02/01 |
| End Date | 2010/01/01 |
| Progress | in-progress |
| Currentness | |
| Location Description | Contra Costa County |
The Lower Walnut Creek Project incorporates a new way of approaching the traditional methods of operating and maintaining a flood control facility. The existing channel is a classic Army Corps of Engineers trapezoidal earth channel that requires ongoing de-silting maintenance. The alternative approach will be to move the channel levees back in the lower reaches to provide additional capacity for floodwaters and to create floodplains. This approach will provide the necessary capacity to handle floodwaters while reducing de-silting costs and creating additional wetlands, riparian habitat and revegetation potential. Other project components include improving fish passage and habitat and increasing recreational opportunities.
The Corps of Engineers' channelization of lower Walnut Creek in the 1960s provided needed flood protection for the lower watershed. But this resulted in a stark, engineered channel devoid of habitat and with Corps' required maintenance that is extremely difficult to accomplish in today's regulatory climate. The channel's flood conveyance capacity has been compromised because of accumuled sediment that the District has been unable to remove. Even without any riparian canopy or quality bed gravels, the channel supports a small fall salmon run, though no data exists to show successful fry emergence. The salmon's upstream progress is blocked by a large concrete drop structure and poaching of spawning salmonids have been an issue.
The project proposes to increase natural sustainability by investigating alternative methods to the traditional configuration and maintenance practices. These methods could include the setback of levees in the lower reach to create a larger floodplain, reconfiguring the channel cross section to provide better sediment transport, while providing additional conveyance capacity, wetlands, riparian habitat and the potential for revegetaion throughout the floodplain.
Recreation,
Flood Protection,
Watershed Management,
Fish passage,
Flood Plains,
Stormwater Management,
Water Quality,
Habitat Protection
Ecosystem Restoration,
Environmental and habitat protection and improvement,
Flood management,
Recreation and public access,
Storm water capture and management,
Water quality protection and improvement,
Wetlands enhancement and creation
Flood Protection & Stormwater Management
