Document Type


Publication Date

January 1983


Executive Summary: A reconnaissance-level study was conducted in Flaming Gorge Reservoir, Wyoming, during the late summer of 1982 in order to determine the possible importance of the sediment sin exacerbating the blue-green algal blooms that occur in summer in the upper reservoir. Sediments can affect phytoplankton dynamics in reservoirs on an annual basis by delyaing the availability of particulate P associated with spring runoff until late summery, when the warm water temperatures and the light climate favor the growth of blue-green algae. Over the longer term, however, sediments that historically have served as a trap for part of the annual phosphous load entering the system may release some of this stored P in response to decreased P concentrations in the overlying water. The decreased concentrations may result from unusally wet water years or, more importantly from a management standpoint, from restoration strategies aimed at reducing inputs of P from the watershed. The resulting internal P loading can delay the anticipated recovery of a reservoir for may years, relative to the recovery rate that owuld be predicted in its absence. The study of lacustrine sediments is helpful in predicting the potential for internal P loading from a particular sediment, as well as the factors more important in controlling P release