9614

• UCREFRP Catalog Number: 9614
• Author: Bowen, Z. H. and e. al.
• Title: Habitat Measurement and Modeling in the Green and Yampa Rivers.
• USFW Year: 2001.
• USFW - Doc Type: \
• Copyright Material: NO

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Control survey
All of the survey techniques used in this study were dependent upon a reliable
network of survey control points. During September 1999 three permanent benchmarks
were established using survey-grade global positioning system (GPS) equipment. These
benchmarks were surveyed from a National Geodetic Survey (NGS) Federal base
network control station in Moffat County, Colorado (designation Y 419, PID LN0394)
and were used as survey control at the study areas. The primary control point, designated
as NRPP1 was established near the headquarters for Dinosaur National Monument. The
other benchmarks were established at strategic locations (e.g., where good GPS reception
was most likely) near the midpoints of both study sites. A repeat survey from the NGS
control point to the primary control benchmark was conducted by a contractor as a check
prior to starting airborne laser mapping work. The independent surveys were in relatively
close agreement; deviations between the USGS and contractor survey for NRPP1 were
0.036 m (x, y) and 0.012 m (z).
Transect surveys
Initial tansect surveys were performed at the Green River site during November
1999 and at the Yampa River site in April 2000. The discharge in the Green River during
the November survey was 73 m3/sec and the discharge during the Yampa survey ranged
from 137 to 142 m%. GPS, wading, and boat-mounted sounding systems were used to
measure cross sections. A high-tension cable was stretched between anchorages
established at the ends of each cross section, and depth measurements were made at