ISFAPPC04246

• Case Number: 00CW0101
• Stream Name: Fourmile Creek
• Watershed: Fourmile Creek
• Water Division: 2
• Water District: 12
• County: Fremont
• Instream Flow App - Doc Type: Supplemental Data

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4.0 RESULTS

4.1 PHYSICAL HABITAT

Little information regarding the physical habitat of the creek was collected. The stream substrate
consisted of cobbles and sediment while the pool-riffle ratio was good.

4.2 MACROINVERTEBRATES

Twenty taxa of macroinvertebrates were collected at Station One, see Table 3. True flies,
caddisflies, and stoneflies were the most abundant groups in the macroinvertebrate sample
collected at this location. The most abundant species were the true fly Hexatoma Slh and the
caddisfly Hydropsyche occidentalis.

At Station Two, 17 taxa were collected. True flies and caddisflies once again dominated. Of
the true flies, the most abundant species was Hexatoma m.. Hydroosyche occidentalis and
Brachycentrus occidentalis were the most abundant species of the caddisflies.

Twelve taxa were collected at Station Three. The caddisfly family continued to dominate the
aquatic community at Station Three. The most abundant groups were the caddisflies
Hydropsyche occidentalis and Brachycentrus occidentalis, as was the case at Station Two.

At Station Four, 13 taxa were collected. The true flies and mayflies were the dominate families.
The true flies had five different taxa represented with only Atherix pachypus being present in
larger numbers. The mayflies Tricorythodes, Baetis insilmificans and Baetis sp. c were the most .
abundant while the caddisfly Hydrojlsyche occidentalis was also dominate.

The total number of macroinvertebrates and the total number of taxa present decreased in a
downstream direction. Dragonflies (Odonata) were common at most of the stations sampled.
__. The presence of dragonflies is not typical of most Colorado brown trout streams..

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4.3 E1SH POPULATIONS

White suckers dominated at Station One and Station 4 while brown trout dominated at Stations
Two and Three (Table 4). The largest number of fish collected was at the uppermost station.
Brook, brown and rainbow trout along with the white sucker, longnose dace, and longnose
sucker were collected at Station One. Brook and brown trout as well as the white sucker and
longnose dace were found at Station Two. Only the brown trout, white sucker, and longnose
dace were found at Station Three. The brown trout, white sucker, lon,gnose dace, creek chub,
longnose sucker, and fathead minnow were collected at Station Four. The brown trout was the
only trout species found at each station.

At Station One, 179 brook trout per acre with an average length of 11.8 centimeters and an
average weight of 22.2 grams were collected (Table 4). Six hundred and forty-three (643)
brown trout per acre with an average length 15 centimeters and an average weigltt of 52.7 grams