The mechanisms that govern the structure and function of benthic macroinvertebrate communities in the Fryingpan River are not entirely understood. For this reason, sampling continued during the Fall 2002 and Spring 2003 as a supplement to the study that occurred during the previous seasons (Ptacek et al. 2003). Releases from the impoundment at Ruedi Reservoir directly influence the benthic macroinvertebrate and fish communities that exist downstream. The influence of regulated discharge on the macroinvertebrate community can result in an increase in thermal stability and extended periods of flow stability. However, it is unknown how the level of discharge during the winter months and the potential formation of anchor ice may influence these communities.

In many ways, the impoundment and physical variables associated with discharge are responsible for the development of an exceptional trout fishery in the Fryingpan River. The purpose of this extended sampling was to evaluate potential impacts associated with low winter flows. This information could be useful when determining management practices that will benefit the trout fishery. The results provided by macroinvertebrate monitoring and accurate identifications can provide a great deal of information pertaining to the flow regime and other aquatic conditions.