07

• Board Meeting Date: 7/11/2007
• Description: IWMD Section - Water Supply Reserve Account July 2007 Grant Allocations
• Board Meetings - Doc Type: Memo

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Section 3 Attachment

Jackson Gulch Reservoir Expansion project

The Mancos 1Nater Conservancy District is within Montezuma County and the Mancos River Drainage
(Mancos Valley). The District serves about 15,000 acres of the Mancos Valley, including the Town of
Mancos and the surrounding rural community, and operates the Jackson Gulch Dam and Reservoir with
almost 5 miles of inlet/outlet canals. The existing reservoir is an off stream storage facility at 7830' MSL
with a capacilY of 10,000 a-fbehind a rock-faced earthen dam. District water is used for irrigation,
municipal, hydroelectric, recreation, livestock, wildlife, environmental projects, wetlands mitigation and
fire protection. The population of the District is approximately 2,350 and is growing moderately. Land use
is primarily ranching (cattle, sheep, horses) and farming (grass and alfalfa hay). The jobs in the Mancos area
include rancher/farmer, logging, construction, teacher, welder, mechanic, administrator, local, state and
federal government and commercial enterprise. The local area has 3 water treatment facilities, the Town of
Mancos, the Mesa Verde National Park and the Mancos Rural Water Company, which together serve
approximately 1200 domestic and commercial water taps.
Following the general trend ofthe state, the Mancos Valley is experiencing a shift in demographics.
Agricultural lands are being subdivided. Demands for new water are changing from primarily agricultural
to commerci2.1 and household purposes. The Mancos Valley is a potential bedroom community for the
Durango area held back by the lack of water to treat for domestic purposes.
The area to be studied is Jackson Gulch dam, reservoir and the borrow pit that was created with the
building of the original dam. The USBR will conduct the feasibility study as outlined in the attached Project
Management Plan:
1. Jackson Gulch Dam. ($80,000 for B.O R Study)
a) The funds will be used to prepare a feasibility level study for increasing the storage capacity
ofthe reservoir, including raising the dam a total of 5'.
b) The study will define structural needs for the Dam and related features.
c) E:~tablish the additional water that can be stored, construction cost estimates and impacts that
must be mitigated.
2. Construction of Lake Mancos Dam, Reservoir and Canals (Jackson Gulch Borrow pit) ($38,000)
a) Develop information on feasibility of a new Lake Mancos Dam in the borrow pit.
b) Geotechnical investigation of the borrow area.
c) Develop information on the enlargement ofthe Crystal Creek Ditch for delivery of water.
d) Provide infOlmation on needed outlet works and additional storage that could be gained.
e) 47% or $18,000 of cost provided by in-kind services.

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