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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O~1740

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These damages are caused by floods originating primarily from
high intensity thunderstorms over the rangelands northwest of Limon.
Storms of this type cause damaging floods on the average of once
every six years, The proposed project will reduce the estimated
damage from the one percent chance floods about ninety-nine percent,

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This work plan outlines a three-year project for installation
of land treatment and structural measures for the protection of the
watershed at a total estimated project cost of $222,044, The Public
Law 566 share of this cost will be ~202,134. Funds from other
sources total $19,910 and include local funds as well as funds
available under other Federal authorities. In addition, the above
organizations will bear the entire cost of operation and maintenance
of the structural measures. This is estimated to be ~1,077 annually.

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Land Treatment Measures

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The watershed area above the proposed floodwater-retarding
structures totals 8,531 acres, It consists entirely of agricultural
rangeland in eight private ownerships and State lands leased to
these owner-operators.

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The cost of proposed land treatment measures to be applied by
the landowners in this area over a three-year period is estimated to
be $12,500. Public Law 566 will not share in these costs.

Structural Measures

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Three floodwater-retarding structures having a total storage
capacity of 1,929 acre-feet are proposed for the three tributary
drainages above the area subject to damage. Of the total, 1,778
acre-feet is allocated to floodwater and 151 acre-feet to sediment
storage. The floodwater detention capacity is equivalent to 2.5
inches of runoff from 13.33 square miles or about 86 percent of the
total watershed area. They will provide flood protection from
storms occurring less frequently than once in a hundred years.

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This plan provides for no storage of water for any purpose and
the sponsors do not propose any in the future.

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The principal spillway flows are through ungated concrete
conduits and these flows will be carried through the project area
in the existing channels. The total cost of the floodwater-retarding
structures, not including operation and maintenance, is estimated
to be $209,544. The average annual cost including operation and
maintenance is $8,649.

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