9593

• UCREFRP Catalog Number: 9593
• Author: Tetra Tech Inc.
• Title: Concept Development Report Hartland Diversion Dam Fish Passage Structure Delta, Colorado.
• USFW Year: 2000.
• USFW - Doc Type: Grand Junction, CO.
• Copyright Material: NO

TABLE 5.1 SUMMARY OF MANNING'S N VALUES USED IN THE GUNNISON RIVER HYDRAULIC
MODEL

Location Manning's n Manning's n Delta County FIS
Channel 0.039 0.032-0.05
River banks 0.045 0.040-0.10
Overbanks 0.070 0.040-0.10
Dam and diversion structure 0.055 na

5.2 Model Results
Calculations indicate that when flows in the Gunnison River are 350 cfs, the head on
the diversions dam is approximately 5 to 6 inches deep at the dam crest and drops a total of
3.1 feet to the toe. At 3000 cfs the head increases to 2 feet and drops a total of 2.4 feet.
When flows in the Gunnison River reach 11,600 cfs (the 5-year event) the head on the dam is
4.8 feet and drops a total of 0.9 feet, essentially submerging the drop. Flows in excess of
11,600 cfs results in submerged conditions as well as overbank flooding in many of the river
sections within the study reach including, the sections upstream of the diversion structure.
Table 5.2 summarizes these water surface elevations at cross sections just upstream and
downstream of the Hartland diversion for the modeled flows. Appendix 0 has a listing of water
surface elevations at all cross sections.

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