A Stream Restoration Case Study in the California Central Coast

摘要

San Antonio Creek is located in the California central coast area within Vandenberg Air Force Base. The creek is actively adjusting its profile and channel geometry and has experienced significant erosion (degradation), deposition (aggradation), channel widening, and bend migration during the recent past. The results of several studies indicate that this trend is expected to continue. The effects of this instability have led to a degraded stream channel environment and hydrologic disconnection of the stream from the surrounding floodplain. In addition to the loss of habitat and wetlands, local infrastructure, such as utilities and highways, and cultural resources are threatened. The purpose of this project was to design scour protection for the infrastructure and to restore form and function to San Antonio Creek within the project area.HDR worked in conjunction with the U.S. Air Force, U.S. Army Corps of Engineers, David Derrick (USACE Waterways Experiment Station), John McCullah (Salix Earthcare), and others to develop a proposed design. The proposed design incorporates seven rock riffle grade control structures that will mitigate the lowering of the channel, provide pool and riffle features, and also provide for fish passage. Additionally, bank toe and slope protection will be provided at key areas. Habitat will be restored with the use of environmentally sensitive streambank stabilization and restoration methods. This is expected to provide enhanced habitat for several endangered species within the creek as well as other species. Additionally, cutting point bars and reshaping the channel will allow for a more natural channel shape with a restored flood terrace.