The biological and physical processes that govern the structure and function of benthic macroinvertebrate communities in the Fryingpan River are not entirely understood. However, there is evidence to suggest that the flow regime may be an important physical influence on benthic communities (Rees et al. 2003). For this reason, macroinvertebrate sampling and thermal modeling continued during the fall 2003 and spring 2004 in the Fryingpan River as part of a study to assess the influence of releases from Ruedi Reservoir. Water releases from the impounded reservoir can influence benthic macroinvertebrates and fish communities through regulation of flow and alteration of the thermal regime. It has been hypothesized that erratic changes in discharge have a negative impact on benthic macroinvertebrates (Ptacek et al. 2003); however, it is not clear 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. Macroinvertebrate monitoring coupled with robust laboratory analysis can provide a great deal of information pertaining to the influence of the flow regime on aquatic conditions.