_GENERAL DOCUMENTS - C1981017 ‎(284)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎
• Media Type: D
• Archive: No

The macro invertebrate biomass was higher at each of the stations in
June; however, this was mainly because of the abundance of tolerant taxa
in the community. All of the DAT Diversity Index values indicated stress
conditions. Most of the taxa having less than resident population numbers
indicated there was instability at each of the stations in this ecosystem.
Impacts were limiting to not only cleanwater and moderately tolerant taxa,
but also to some tolerant taxa.
The potential for fisheries in this stream appeared to be poor ,
particulary at the lower three stations, where the macro invertebrate
biomass was lower than one would expect in a stream with 128 to 185 mg/l
alkalinity. Such a stream should have about 4.0 g/m2 macro invertebrate
biomass. The 65 mg/1 sulfate found at Station 2 would be limiting to
sensitive macro invertebrate species, and the sulfate of 52 at Station 3
was also within the threshold range of some of the most sensitive
mayflies. The number of cleanwater species found at each of the stations
indicated there may be little, if any, suitable spawning substrate
available.
In April , the BCI value of 96 at the upper station indicated that
ecosystem was close to its potential, and of 74, 72, and 77 at Stations 2,
3 , and 4, respectively, indicated just fair conditions there. Most species
were not present in resident population numbers, which indicated even more
stress in this ecosystem than was indicated by the BCI values.
When sampled in June, the BCI values of 78 and 79 at Stations 1 and
2, respectively, indicated just fair conditions in those stream reaches. A
BCI of 85 at Station 3 indicated conditions were fairly good there;
however, many of the taxa still had less than resident population numbers.
The BCI of 69 at Station 4 indicated severe stress conditions in that
stream reach. It appeared there would be opportunities for management to
improve instream habitat conditions, water quality, and possibly riparian
habitat quality in this aquatic ecosystem. It appeared there may be some
toxic effluents from the mine operation in this aquatic ecosystem.
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