FLOOD01459

• County: Gunnison
• Community: Uncompahgre Valley
• Title: Upper Gunnison-Uncompahgre Basin Phase 1 Feasibility Study Summary Report
• Date: 5/1/1989
• Prepared For: Colorado Water Resources and Power Development Authority
• Prepared By: HDR Engineering, Inc.
• Floodplain - Doc Type: Project

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4.5 FUTURE WATER AVAILABILITY WITH NO DEVELOPMENT

The hydrologic model discussed previously was operated to evaluate the
abil ity of the Study Area's current water suppl i es to meet forecasted water
demands. The Moderate Demand Scenario was used to investigate this "No-Action
Alternative. .

Municipal and industrial (M&I) demands for very small systems in the
basin were not explicitly modeled. Of the 12 M&I demands explicitly
represented in the basin model, shortages occurred to only one; a mining
demand of 120 af per year located near Crested Butte. Occasional shortages to
this demand occur because of a combination of limited physical supply and the
fact that its water right has a very junior priority.

Agricultural demands in this No-Action Alternative are those associated
with providing a full water supply to currently irrigated lands; no new lands
are assumed to be brought into production. Shortages to these irrigation
demands are summarized in Table 4.2. The shortages shown in the table are
shortages to depletion demands; shortages to headgate diversion demands may be
up to four times the shortages shown in the table and divers i on shortages
would occur more frequently than indicated in the table.

Further evaluation of these agricultural shortages indicated that the
predicted Blue River sub-basin shortage may be overstated. Records of
irrigated acreage in this sub-basin are poor to non-existent and could be the
cause of overstating the demands. Also, the level of detail of the model
makes verification of the adequacy of water supply in this particular
sub-bas i n di ffi cult. It was also determi ned subsequent to model i ng that
recent purchases of large tracts of land in the sub-basin have resulted in
significant amounts of land being taken out of production. In addition,
discussions with the Water Commissioner of that District revealed that
significant shortages have not occurred historically in the Blue River service
area. For the purposes of this study, therefore, the Blue River sub-basin was
not considered to be an area with significant agricultural water shortages.