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The Trinity River Restoration Project Office (TRRP) proposes to modify the existing floodplain and bar deposits at two sites along the Trinity River within Trinity County between Junction City and Douglas City, California. The two sites are Evans Bar located between River Mile 84.25 and 85.1 and Dutch Creek Bar located between River Miles 85.5 and 86.1 (shown on Figures 2 and 3). The proposed modification at each site includes lowering portions of the existing floodplain and excavating side channels into the remaining floodplain. Spawning gravel processed from these sites or other nearby sites would then be introduced into the proposed side channels and into the adjacent Trinity River channel for in-stream replenishment or augmentation of Salmon and Steel-Head spawning gravel.

 

At the request of Reclamation’s Trinity River Restoration Office, Matthew Merson and Steven Sherer, geologists with the Mid-Pacific Region Geology Branch, conducted a field exploration program to eologically characterize available stream-side deposits at the two sites along the Trinity River (Figures 1 through 3). The exploration program was conducted to 1) determine the feasibility of processing gravel at each of the sites for possible in-stream spawning gravel replenishment, 2) determine the quantity of undesirable (waste) materials at each site if processing occurs, 3) determine the best location to dispose of waste materials at each site, 4) determine if bedrock would be encountered in the excavation of side channels at each location, and 5) to determine the elevation of groundwater at each test pit location.