10825 Water Supply Alternative Summary Phase 2 Assessment January 2008 Draft

• Description: A report from the Grand River Consulting Corporation on alternatives for delivering 10,825 AF of water to the 15-mile reach of the Colorado River.
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/2008
• Author: Grand River Consulting Corporation
• Title: 10825 Water Supply Alternative Summary Phase 2 Assessment January 2008 Draft
• Water Supply Pro - Doc Type: Report/Study

development of additional forecasting procedures, it may be possible to release Green
Mountain Reservoir HUP surplus water earlier in the summer. This would allow releases from
Ruedi Reservoir to be spread -out over a longer period of time, which would decrease any
negative impacts associated with this alternative.
8.2 SULPHUR GULCH RESERVOIR (Alternative B)
This alternative provides releases of 10,825 acre -feet from a 16,000 acre -foot Sulphur Gulch
Reservoir in all years. This structural option is the closest to the 15 Mile Reach, is simple to
manage, and will most efficiently provide water to the 15 Mile Reach. Potential negative
impacts to the endangered fish can be minimized or eliminated with proper design and
operational considerations. Sulphur Gulch Reservoir would likely be the Least Environmentally
Damaging Practicable Alternative (LEDPA) of all of the new reservoirs considered in this study.
Secondary objectives of the study are partially met with this alternative. While releases from
Sulphur Gulch do not provide any new benefits to the Colorado River below Lake Granby,
releases from Sulphur Gulch Reservoir do not create any new negative impacts in the Fryingpan
River, the Roaring Fork River, or the upper Colorado River.
Several West Slope stakeholders have been concerned with potential water quality impacts that
may be associated with the operation of Sulphur Gulch Reservoir. In a recent Water Court
settlement, the water right applicants for the reservoir agreed to implement certain operational
criteria to minimize any potential for water quality degradation. In return, the concerned West
Slope stakeholders agreed "not to raise and to not encourage others to raise, any issues related
to the salinity of and total dissolved solids in water to be diverted and stored in and released
from the Sulphur Gulch Reservoir in any applicable permitting processes for the Sulphur Gulch
Reservoir... and pumping plant and pipeline." No substantial water quality impacts are
associated with the proposed Sulphur Gulch Reservoir assuming the project is operated in
accordance with the terms of the settlement.
Water from Sulphur Gulch Reservoir can be effectively integrated into the overall Recovery
Program. This alternative can release water at anytime during the summer and fall months, and
will complement late summer (typically September and October) releases from the Green
Mountain Reservoir HUP and from the Wolford Mountain Reservoir fish pool.
8.3 SULPHUR GULCH RESERVOIR PAIRED WITH RUEDI RESERVOIR (Alternative C1)
This alternative pairs new reservoir construction at Sulphur Gulch with the existing Ruedi
Reservoir. A total of 5,412 acre feet would be delivered from each reservoir to meet the
primary objectives of the 10825 Water Supply Study. Water released from Ruedi Reservoir
would be "base loaded ", or released at a relatively constant rate to reduce potential impacts to
t
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