Assessment of the effects of impingement and entrainment on the fish community of the New River, Virginia

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Virginia Polytechnic Institute and State University

The loss of organisms to cooling water intakes has been identified as having an impact on aquatic biota. Impingement and entrainment of organisms are unavoidable if natural waters are to be used by utilities for cooling water purposes. This study was initiated to determine the effects of operation of the intake of the Glen Lyn Power Station on the fish community of the New River, Glen Lyn, Virginia.

Estimates of the numbers of fishes impinged by the Glen Lyn Power Station were made for the period mid-May 1976 through May 1977. The estimated total impingement was 6219 fish of 22 species. The alewife (Alosa pseudoharengus) accounted for 86.6% of the fish; most of these were impinged during the winter probably as a result of cold induced mortality in an upstream reservoir population. The estimated numbers of other species impinged ranged from 6 to 182. Most of the fish were dead prior to impingement.

An estimated 30,200,000 larval fish of an estimated 172,000,000 that drifted by the Glen Lyn Power Station during June 1976 through May 1977 were entrained by the power station. Larvae of the carp (Cyprinus carpio) accounted for 94.8% of the ichthyoplankton drift. Estimates of 14.5 to 21.7% of the larvae of selected representative species that drifted by the power station were entrained.

The criteria listed by the United States Environmental Protection Agency for assessing the impact of intake operation on aquatic communities were used in conjunction with collected data and information on the fish community of the New River available in the literature. It was concluded that the losses to the intake of the Glen Lyn Power Station were not significant enough to affect the fish community structure of the New River near Glen Lyn, Virginia in its present condition.