DOE protects suitable fish habitat along the banks of the Colorado River near the Moab site by augmenting the natural flow with additional river water. This activity, called surface water diversion, is performed when a suitable habitat area is present or imminent.
During spring runoff, the river level rises, inundating most riverside channels, which are not part of the main flow. As spring runoff ends and the river level falls, some of these channels close at the upstream end, creating backwater pools. These backwater pools serve as suitable habitat for endangered fish species.
Ammonia dissolved in ground water discharges to the river at a very low rate. The ammonia concentration discharging to backwater pools where the flow is almost stagnant can be sufficient to be harmful to fish species. Each year, DOE observes the channels near the Moab site for the development of backwater pools. The ammonia concentration in pools is measured, and additional river water is diverted to the areas as necessary to maintain levels of ammonia below harmful concentrations. The river flow and areas where backwater pools are likely to form are monitored through the end of September, when young-of-year fish are no longer present.
See Current Status - Ground Water Interim Action for the latest information on surface water diversion. The results of surface water diversion are discussed in monitoring reports.