PROJ00072

• Contract/PO #: C153592
• Contractor Name: West Divide Water Conservancy District
• Contract Type: Loan
• Water District: 0
• County: Garfield
• Bill Number: SB 89-85
• Loan Projects - Doc Type: Feasibility Study

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CHAPTER 5
PLAN OF DEVELOPMENT

5.1 Physical Plan:

The Alsbury Reservoir Project consists of the reconstruction and

enlargement of an existing dam on the headwaters of East Divide Creek. Maximum

height of the dam will be 25 feet, which will provide for storage of 255

acre-feet of water. Plan and sections of the dam are shown on Figure 5.1. The

water will be released to the stream at the request of contractors for the

water. The water will be used primarily for irrigation of hay fields in the

vicinity of the confluence of East and West Divide Creeks. It will be diverted

from the creek through existing irrigation ditches. A small amount of storage

space (probably not more than 10 acre-feet) will be held in reserve as a source

of augmentation water for wells supplying individual residences. Water released

for this purpose will remain in the stream to counterbalance the effect which

pumping from the wells might have on the surface water supply.

5.2 Regional Geology:

The Alsbury Dam site is located near the eastern margin of the Colorado

Plateau physiographic province. The Grand Hogback, a steeply dipping monocline

immediately north and east of the area, forms the boundary between the Colorado

Plateau and the Southern Rocky Mountain Physiographic provinces.

The site is situated on the east flank of a major geologic fold, the Divide

Creek Anticline. Some faults are present near the crest of the fold. Bedrock

in the area is mostly the Wasatch Formation of Tertiary age, but the Mesaverde

Formation has been exposed by erosion on the crest of the anticline. Figure 5.2

shows the generalized regional geology.

Bedrock at the Alsbury Dam site is the Wasatch Formation which is up to

5,000 feet thick and consists of claystone, siltstone, and lenticular sandstone.

The formation is of fluvial origin (stream-deposited sediments) and was formed

in the Paleocene-Eocene epochs of the Tertiary period. The claystone and

siltstone layers are commonly poorly cemented and compacted and often form

landslides or mudflows on steep slopes, especially when wet.

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