North Fork Battle Creek, Eagle Canyon Fish Passage Assessment
Eagle Canyon is located on the border of Tehama and Shasta counties in Northeastern California and is on the North Fork Battle Creek; a tributary to the Sacramento River. North Fork Battle Creek is as an important watershed for anadromous salmonids and Eagle Canyon has been identified as a barrier to migrating fish. Battle Creek has historically been critically significant habitat for Central Valley spring-run Chinook salmon (state- and federally listed as threatened), the Sacramento River winter-run Chinook salmon (state- and federally listed as endangered), and the Central Valley steelhead (federally listed as threatened). In 1999 multiple government agencies, Pacific Gas and Electric (PG&E) and non-government organizations created a partnership establishing the Battle Creek Salmon and Steelhead Restoration Project to restore approximately 42 miles of habitat.
Eagle Canyon is a narrow gorge that is over 200 feet deep with walls that are nearly vertical. Several large rocks in the channel are fish barriers that jeopardize the success of the Restoration Project. Two very large rock barriers are the focus of this project. One barrier is located approximately 600 feet downstream from the PG&E’s Eagle Canyon Diversion Dam, and the second barrier is approximately 1,000 feet upstream of the dam. The downstream barrier occurs within a debris field created by blasting associated with the construction of a tunnel and elevated flume. The upstream barrier is a 250-foot reach of rock-fall debris that has locally buried the channel with car-and bus-sized blocks of rock. Both sites occur in remote and very rugged locations that are not accessible by terrestrial vehicles.
GMA was tasked with documenting existing topographic conditions at the two separate sites in Eagle Canyon. Due to the complex nature of the boulders and terrain, data acquisition was achieved using multiple sources. The bulk of the data was acquired using a terrestrial laser scanner (TLS), producing a high resolution point cloud capturing all exposed surfaces of rocks and voids between boulders. Total station surveys were used to fill in areas not captured by the laser scanner, such as bathymetric and highly vegetated areas. Single beam sonar was deployed using a 3-foot mini-cataraft to acquire data in areas of deep or high velocity water. Aerial photos and additional point cloud data were acquired using a small unmannd aerial vehicle.
The TLS, LiDAR, sUAS, single beam sonar, and conventional survey data were integrated to produce various products including point cloud data sets, a mesh surface, and a Triangulated Irregular Network (TIN) surface that were used for hydraulic analysis and engineering design.