FLOOD10335

• County: Mesa
• Stream Name: Indian Wash
• Basin: Colorado Mainstem
• Title: Watershed Work Plan - Indian Wash Watershed, Mesa County, CO
• Date: 9/1/1961
• Prepared By: Upper Grand Valley Soil Conservation District
• Floodplain - Doc Type: Flood Mitigation/Flood Warning/Watershed Restoration

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Several disturbed samples. of possible borrow materials were
obtained for laboratory analysis. Some of these samples tested high
in soluble salts, and a number of additional samples were collected
to.be tested for the presence of soluble salts. Results of these
tests. indicated. that ~dequate amo~nts of. borrow materials with
relatively low percentages of soluble salt could be obtained within
a reasonable distance from the dam site. The upper few feet of
material in the borrow areas generally appeared to be lower in soluble
salt content.

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Economic Investigations

The evaluation of flood damages and benefits associated with
works of improvement proposed in this plan were based on items of
~~rrent and historical record to the greatest possible extent. Damage
investigations and evaluation methods used in this plan comply with
procedures described in the Economics Guide for Watershed Protection
and Flood Prevention.

Long-ter.m projected prices (Agricultural Price and Cost
Projections, 1959, by the Agricultural Research Service and the
Agricultural Marketing Service). were used in c~puting monetary
damages, benefits, and operation and maintenance costs. Current
(1961) prices were used to estimate structural installation costs.
Federal and other costs were amortized at 2 5/8 percent interest
for SO years.

All damage calculations were correlated with those developed
_ by the U. S. Corps of Anny Engineers during the preliminary investi-
gation. Damages were also correlated with the damage and extent of
flooding caused by the stonn of June 6, 1958;-

The damage and benefit evaluation of Indian Wash Watershed is
divided into three main reaches. The first, and relatively the most
important, is the damage area of Indian Wash proper which includes all
of the area subject to overflow by Indian Wash fram above F-Road down
to Grand Avenue. The second, includes all of the area to the east
of Indian Wash betwen 29 and 30 Roads fran the High Line Canal down
to the business route of U. S. Highway 6-24. The third, includes the
area of flooding along the north side of the Denver and Rio Grande
Western Railroad mainline track fram 29~Road west to 12th Street
(see Damage Location, Map, Figure 1).