WSP05425

• File Number: 8101
• Description: Arkansas River Basin Description
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 9/1/1962
• Author: High Plains SCD
• Title: Watershed Work Plan - Limon Watershed Protection Project - Elbert and Lincoln Counties - Colorado
• Water Supply Pro - Doc Type: Report/Study

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Future rates of sedimentation at the proposed reservoir sites
with the project installed were determined as being 0,23 acre-foot
annually per square mile of drainage area at site 1-1, 0,22 acre-
foot at site 1-2, and 0.21 acre-foot at site 1-3, Capacity
equivalents for sediment storage in the reservoirs are 0,22, 0.21,
and 0.20-inch respectively,

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Since most of the sediment carried to the reservoirs will
consist of fine-grained materials (clay, silt, and fine sand), it
is believed that almost all of the sediment will be deposited
within the reservoirs below the emergency spillway crest elevation.

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In order to obtain an indication of the stability of the
stream channels below the proposed structure sites, mechanical
analyses were made on several representative samples of materials
underlying these channels. All of the sa~mples were found to
contain a fairly high percentage of clay. It was concluded that
the channels would be relatively resistant to down-cutting from
the flows expected to occur with the project installed.

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Economic Investiqations

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The evaluation of flood damages and benefits associated with
worts of improvement proposed in this plan were based on historical
records, Damage investigations and evaluation methods used in this
plan follow procedures described in the Economics Guide for
Watershed Protection and Flocd Prevention,

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Long-term projected prices (Agricultural Price and Cost
Projections, 1957, by the Agricultural Research Service and the
Agricultural Marketing Service) were used in coroputing monetary
damages, benefits, and operation and maintenance costs, Current
(1962) prices were used to estimate structural installation costs,
Federal and other costs were ~nortized at 2 5/8 percent interest
for 50 years.

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Agricultural damages occur in the floodplain areas above and
below the Town of Limon and consist primarily of crop and pasture,
fences, and debris. These damages were evaluated by projecting
historical data,

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The principal damages occur along the West, Middle, and
East channels through the Town of Limon, Damages were grouped
into three categories: (1) residential, (2) corrmercial, and
(3) municipal which includes public schools and churches.

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