Sand Hill River Rock Riffles and Fish Passage
In the 1950s, the US Army Corps of Engineers (USACE) completed a flood control project which involved the construction of the Sand Hill Ditch. Due to significant slope found in portions of the USACE project area, four large concrete drop structures were installed on the Sand Hill River as part of the flood control project. During normal flows, each of these concrete drop structures create a vertical drop of approximately five feet. Since the original construction of the Sand Hill Ditch by the USACE, the channel has downcut significantly, causing bank stability issues and subsequent slope failures as the slopes became steeper and the channel bottom became lower.