USE OF WATERSHED CHARACTERISTICS TO SELECT CONTROL STREAMS FOR ESTIMATING EFFECTS OF METAL MINING WASTES ON EXTENSIVELY DISTURBED STREAMS

Impacts of sediments and heavy metals on the biota of streams in the copper-mining district of southwestern Montana were examined by comparing aquatic communities of impacted streams with those of control streams. These results revealed that: chemical and physical habitats at the impacted sites were disrupted, the presence of trout was an inadequate measure of ecological integrity for these sites, and watershed classification based on a combination of mapped terrestrial characteristics provided a reasonable method to select control sites where potential control sites upstream and downstream were unsuitable. Refs.