Dames & Moore, 1999 - USDA Forest Service

Macroinvertebrate sampling included the collection of eight replicates per site which were applied to seven
indices to measure the community health or impairment, including species richness, ratio of scrapers and
filtering collectors (types of aquatic insects), ratio of specific benthic insects species (EPT, or
Ephemeroptera, Plecoptera, and Trichoptera) to the abundance of certain specific species (Chirononmidae),
percent contribution of dominant taxa, an EPT index, a community loss index, and ratio of shredder
functional feeding group to the total number of individuals collected. The total number of organisms was
also used as an indication of community health or impairment.
The fish surveys were conducted in the Railroad Creek and the reference reaches by utilizing snorkel and
electrofishing methods in all but two of the stations. Increasing water levels resulting from a storm event
precluded sampling by electrofishing methods at the South Fork of Agnes Creek site. The presence of
spawning Kokanee salmon precluded the use of electrofishing methods at the Company Creek sampling
location.
The results of the two fish sampling methods were found to be relatively consistent. However,
electrofishing methods resulted in higher fish counts at sites where debris andlor bank overhangs were
present which reduced visibility for the snorkeling method. The number of fish presented herein is
calculated based on the actual number of fish for the sampling station area multiplied to correspond to fish
per hectare, or approximately 2-112 acres per hectare, an intern at ion;^ standard area for fish surveys.
No indications of gross abnormalities or disease were noted in the surveys completed by others (PNL, 1992)
and Dames & Moore.
The control areas or reference reach segments of Railroad Creek were selected based on the results of a
literature review, interviews with knowledgeable parties, development of key habitat variables, analysis of
candidate reaches, and a limited field reconnaissance. Observations made during the aquatic survey allowed
for a more thorough assessment of the comparability of the references with the appropriate Railroad Creek
stations adjacent to and downstream of the Site to be conducted.
The following presents the results of the RI aquatic biota survey from upstream to downstream in Railroad
Creek.
Railroad Creek Reaches
Upstream Stations RC-6 and RC- 1
RC-6 was located at the Glacier Peak Wilderness boundary, whereas RC-I was located approximately 120
meters downstream of RC-6. The sites were selected as references or controls for the segment of Railroad
Creek between RC-9 and RC-7, described below. The references for the remainder of the downstream
Railroad Creek segments are discussed later in the Stehekin River Watershed Reference Reaches subsection.
The average total number of benthic macroinvertebrates collected in the eight replicate samples at RC-6 and
RC-1 were 1006 and 1065 per square meter, respectively. The actual values in the replicate samples ranged
from 330 to 1560 per square meter at RC-6, and 650 to 1700 per square meter at RC- 1.
1769~-005-019~uly 28. 1999;10:24 AMDRAFT FINAL R1 REPORT
P