The geomorphic assessment included assembly and analysis of several datasets pertaining to site hydrology, soils, geology and historical conditions. An analysis of the geomorphic landforms of the entire Ukiah Valley has provided a “big-picture” perspective of the channel conditions surrounding the project site. These analyses have revealed past and current processes of erosion and sediment transport which were extrapolated to estimate future meander activity and potential erosion rates. This information was then used to develop recommended mining setback limits and shoreline restoration treatments.
Our staff worked closely with the Client and NOAA Fisheries to develop a design that minimized impacts to the river environment and wildlife resources. The project design incorporates an overflow weir and “fuse plug” that will function to equilibrate the river and pit water levels while reducing the potential for fish entrapment during lower frequency flood events. Channel restoration designs included the excavation of geomorphically appropriate terraces along Ackerman Creek and the Russian River to provide an improved riparian corridor, enhanced bank stability, and high-flow refuge for salmonids.