WSP04624

• File Number: 8220.145.A
• Description: La Plata Project ‎(New Mexico)‎
• Basin: San Juan/Dolores
• Date: 4/1/1944
• Author: USDOI/BOR
• Title: La Plata Project: Colorado-New Mexico - Project Investigations Report No. 32-A
• Water Supply Pro - Doc Type: Report/Study

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PRClT.ECT WORKS

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Long Hollow Dam and Roservoir

Long Hollow Rosorvoir would bo formed by the construction of an
oarth-fill dam, 142 foot high above tho streambed, across Long Hollow
at a site 3 milos southoast of Fort Lewis, Colorado. (See drawing
56-D-452). An auxiliary dike about 3,000 feot long would be required
in a saddlo to the east of tho dam. Tho drainago area tributary to
Long Hollow Reservoir site is vory small; consequently, a spillway
consisting of an unlinod cut in shale, 100 foot wido with a capacity
of 400 second-foot would bo adequato.

The capacity of the rosorvoir would bo 14,000 acre-feet, with
normal water lovel at elovation 7410. Dead storage of 2,000 acre-feet
would leave 12,000 acre-feet for irrigation purposos. Roservoir rights-
of-way, including miscellanoous improvements to be flooded, and the
rolocation of a short soction of road and a pipoline, are ostimated to
cost about $40,000.

Canals

A feeder canal of 400 socond-foot capacity would divert water
from La Plata River near Fort Lewis and extond 4 miles southeast to
the west branch of Long Hollow. The canal would be in earth section
of moderato cross slopo, and could be constructed without difficulty.

An outlet canal of l20 second-foot capacity, with water surface
at olevation 7350, would extond from the rosorvoir in a westerly
direction for a distance of 9 miles to La Plata River. Beyond La Plata
River the outlot canal, roduced to a capacity of 20 second-feet, would
run in a northwestorly direction for about 4 miles to Rattlesnake Gulch.
The greater part of this canal would bo in earth section and loose rock
having an average cross slope of 20 percent. About 300 feet of con-
crete bench flume would bo required.

Existing lateral systems are adequate for the distribution of
water to the farms in tho Colorado division.

State Line Dam and Reservoir

State Line Reservoir would be formed by a dam across La Plata
River in New Mexico, one mile below the Colorado-New Mexico atate Line.
The reservoir would extend over two miles upstream. While the total
capacity would be 32,000 acre-feet, only l2,OOO acre-feet would be
available for irrigation purposes; 5,000 acre-feet are assigned to
silt control and 15,000 acre-feet to flood control.

The dam would be
above the streambed.
spillway on the right
20,000 second-feet.

an earth fill with a maximum height of 122 feet
(See drawing No. 56-D-l,2il). An uncontrolled
abutment is designed to pass a maximum flow of

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