WSP07697

• File Number: 8240.200.10.B
• Description: UCRBRIP - Riverine Fish Flow Investigations
• Basin: Colorado Mainstem
• Date: 7/1/2001
• Author: CDOW
• Title: Riverine Fish Flow Investigations 2001
• Water Supply Pro - Doc Type: Publication

One of the greatest hindrances to using sonar to map the channel bottom is that there is

a mini mum depth requirement. In order for the sonar to get a reading off the bottom of the

channel, the transducer must have at least half a meter of water underneath it. The transducer

was located approximately IScm underwater as to give room to roll and minimize air

entrainment under the transducer head making it difficult to gather bathymetric data in areas

shallower than 7Scm.

2000 Yampa River, Sevens

On July 121999, bathymetric data was collected along a l.3km section of the Yampa

River at the Sevens study section using the GPS/sonar technique. The length ofthis site was

felt to be fairly short given the nature of the associated fish data and the habitats represented

in this reach. The Sevens site was enlarged on June 23, 2000 by surveying another 1.3km

immediately upstream and overlapping the site mapped the previous year. The survey in 2000

used the sample boat and GPS/sonar equipment in both years. In order to compare bed and

water surface elevations between years, three longitudinal profiles were made in the 1999 site

and water lines were recorded for the entire 2.6 km station. Collection of bathymetric data

was hampered in 2000 by the low and unusually short runoff period.

The base pin established in 1998 was used as the reference position for both the 1999

and 2000 surveys. Bathymetric data was collected using the same boat, GPS and sonar

equipment in both years. Shoreline and water surface shots were made using the Psion data

collector running Field Face software. The waterline was surveyed on October 30 and 31,
2000

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