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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terrain. Small errors were associated with relatively flat terrain and large errors were

• observed on very steep, rocky slopes (Bowen and Waltermire 2002 in press).
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Bathymetry

Bathymetric data were collected concurrently with the transect data using the
boat-mounted GPS and echo sounder method described previously. Whereas the transect

data were collected by traversing the stream at a right angle to the stream flow,
bathymetry data were logged longitudinally and along diagonals between transects,

• moving from upstream to downstream for each course. Additional point data were
collected with GPS and conventional surveying instruments to define topography of bars,

islands, secondary channels, and shorelines, and to provide for interpretation of LIDAR
data.

Composite habitat mapping
As a general procedure, a two-dimensional hydrodynamic simulation model
•
(Ghanem et al; 1994, 1996) and a GIS were used to generate habitat classification maps
for a range of discharges at each site. Output from the two-dimensional hydraulic model

was exported to the GIS, where it was converted into a raster (grid) format and re-
classified. The result of rasterization was a mosaic of aquatic habitat patches having

specific characteristics defined by depth and velocity. The GIS was used to quantify the
area of different habitat class types at each of the simulated discharges. These results

were used to generate a graph of habitat class area versus discharge for both study sites.