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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C:.1756

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The maximum rainfall for a daily period recorded during 52
years of record at the weather station at Limon occurred April
25, 1935 when 3.87 inches were measured.

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The selected flood detention storage of the reservoirs is
1,778 acre-feet. It is equivalent to 2.5 inches of runoff from
a total storm precipitation of 4.9 inches occurring in a six-hour
period.

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This precipitation amount is in excess of that shown for the
lOO-year, six-hour amounts in Weather Bureau Technical Paper No. 40
and the Colorado Engineering Handbook for Work Unit Staffs, The
2.5-inch depth was used to develop the floodwater storage based on
a combination of (1) storm depth, (2) hydrologic condition of
watershed, (3) storm duration, and (4) rate of principal spillway
release,

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The storage will therefore regulate the 100-year frequency
storm event through the principal spillway without appreciable
emergency spill;/ay discharge. The channels will have capacity
for the one-hundred year combined routed flow from the unreservoired
area and flows fram the principal spillways of the three
floodwater-retarding structures.

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These structures provide the most economical storage and a
high degree of protection consistent with design, hydrologic, and
other factors involved.

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WORKS OF IMPROVEMENT TO BE INSTALLED

Land Treatment Measures

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Emphasis will be placed on the establishment of land treatment
measures that will aid in the reduction of floodwater and sediment
damages, The quantities and the estimated costs of land treatment
measures to be installed by the owners and operators are shown in
Table 1.

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Measures to be applied on the rangeland will include proper
range use, contour furrowing, and wells. Proper use will assure
improvement, protection and maintenance of vegetative cover. This
will have a definite effect in reducing rates of runoff and sediment
production. The construction of wells will assure more uniform
grazing by reducing livestock concentrations in srr,all areas, Such
concentrations of livestock tend to destroy plant cover over these
areas. Strip cropping and stubble mulching will reduce runoff and
soil erosion on the dry cropland.

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