Colorado River Fish Inlet/Outlet Design
Mesa County, Colorado
Western Water & Land was responsible for the hydrologic elements in the design a fish inlet and outlet for a sand and gravel mine pit lake on the floodplain of the Colorado River. The goal of the project was to provide habitat to endangered fish on the river, reduce the possibility of permanent capture of the pit as a river channel, and allow the pit to reclaim itself over time through the sedimentation process. The project involved the following regulatory agencies: Division of Reclamation, Mining, and Safety (DRMS), Colorado Department of Public Health and Environment (CDPHE), Colorado Water Quality Control Division, U.S. Army Corps of Engineers (USACE), and U.S. Fish and Wildlife (USFW). Because the project area involved a reach of the Colorado River undergoing USFW management of endangered fish, frequent communications were conducted with USFW personnel to understand their primary concerns including a preferred design of the inlet and outlet structures and geometry of the pit lake. Hydrologic modeling of the river required two separate surveying phases and was complicated by split flow conditions caused by a large island within the study area reach. The final modeled domain included approximately 2.5 miles of river channel and a total of 27 survey transects. A rating curve (discharge vs. stage) was established that greatly aided model calibration. The model results were used to support the inlet and outlet design spill elevations, as well as understand potential river velocities and turbulence associated with the inlet and outlet structures.
Mesa County, Colorado
Western Water & Land was responsible for the hydrologic elements in the design a fish inlet and outlet for a sand and gravel mine pit lake on the floodplain of the Colorado River. The goal of the project was to provide habitat to endangered fish on the river, reduce the possibility of permanent capture of the pit as a river channel, and allow the pit to reclaim itself over time through the sedimentation process. The project involved the following regulatory agencies: Division of Reclamation, Mining, and Safety (DRMS), Colorado Department of Public Health and Environment (CDPHE), Colorado Water Quality Control Division, U.S. Army Corps of Engineers (USACE), and U.S. Fish and Wildlife (USFW). Because the project area involved a reach of the Colorado River undergoing USFW management of endangered fish, frequent communications were conducted with USFW personnel to understand their primary concerns including a preferred design of the inlet and outlet structures and geometry of the pit lake. Hydrologic modeling of the river required two separate surveying phases and was complicated by split flow conditions caused by a large island within the study area reach. The final modeled domain included approximately 2.5 miles of river channel and a total of 27 survey transects. A rating curve (discharge vs. stage) was established that greatly aided model calibration. The model results were used to support the inlet and outlet design spill elevations, as well as understand potential river velocities and turbulence associated with the inlet and outlet structures.