8251

• UCREFRP Catalog Number: 8251
• Author: Rakowski, C. L. and J. C. Schmidt.
• Title: The Geomorphic Basis of Colorado Squawfish Nursery Habitat in the Green River Near Ouray, Utah.
• USFW Year: 1996.
• USFW - Doc Type: #93-1070,
• Copyright Material: NO

Draft Fmal Completion Report to UDWR for Contract #93-1070. Amendment 3

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The utilized complexity index was calculated as:

c- Perimeter
2x(nxArea)1/2

This index is the ratio of the perimeter of the water to the circumference of a circle of the same area. The ARC/INFO

software was used to calculate the shoreline length of water and the area of water and submerged sand. The shoreline

development index was then calculated and compared to the area of available habitat for each sampling date.

We used these da ta to discern if:

1) a significant correlation between the calculated complexity indices and the area of available habitat existed, and

2) given a correlation, the relationship varied from year to year with changing channel morphology.

The 1963 data for the 1 O-km _reach within the Ouray NWR were extracted from the larger data set of Schmidt

(1996, unpublished manuscript), aDd the same analysis as described above was performed. The scale of the maps

developed from the 1963 aerial photos was proportionally adjusted. The magnitude of the adjustment was determined

by comparing centerline lengths for the 10-km reach from the USGS quads and the Reclamation basemap Uunbert

Conformal Conic projection to the digitized 1963 maps. The USGS quad and Reclamation basemaps yielded similar

lengths, but it was necessary to multiply the length statistics from the 1963 maps by a factor of 1.27, and the area

statistics by 1.62, to maintain proper proportionality.

UDWR Nursery Habitat Surveys

UDWR conducted nursery habitat sampling three times each year. In the spring, prior to flooding, the

sampling assessed the location. condition and populations of fish after winter low flows. Typically, discharge at that

time was somewhat higher than during summer base flows. Sampling in late July and early August occurred after larval

fish had been transported into the study reach. The discharge during sampling was near base flow (50 m3fs). The fall

sampling assessed growth of the juvenile fish during the summer.

UDWR field crews seined fish and measured physical parameters at each sampled habitat. Physical

measurements included temperature, length. and width at the mouth, middle, and upper part of each backwater, The

depth of the water and depth to firm substrate was measured at three evenly spaced points on each width transect AU