FLOOD10136

• Designation Number: 114
• County: Chaffee
• Community: Poncha Springs
• Stream Name: South Arkansas River/Poncha Creek
• Basin: Arkansas
• Title: FIR - South Arkansas River/Poncha Creek, Poncha Springs, CO
• Date: 3/1/1978
• Designation Date: 11/1/1978
• Prepared By: WRC, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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A wavy line across the floodplain is shown in plan on Plates 3 through

6. This line represents the approximate location where the water surface

elevation for th~ 1% chance flood crosses the 10 foot contour interval.

The legend for each of the four plates shows a numerical number printed

next to this line. However, for clarity and space availability, the print-

ing of the numerical elevation for the individual lines was deleted.

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GLOSSARY

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Aspect

The general basin orientation from a higher to a
lower point in relation to east, west, north, and
south directions.

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Backwater Effect

The rise in surface elevation of flowing water
upstream from and as a result of an obstruction
of flow.

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Channel

A natural or artificial water course of perceptible
extent with definite bed and banks to confine and
conduct continuously or periodically flowing water.

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Cloudburst

A sudden and extremely heavy downpour of rain
is small in areal extent; of short duration;
may be accompanied by lightning, thunder, and
gusts of wind.

that
and
strong

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Correlation

The process of establishing a relation between a
variable and one or more related variables.

Confluence

A point where two or more streams meet.

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Conveyance Capacity a. Channel conveyance capacity is the rate of dis-
charge, in cubic feet per second, which can flow
in a water course with the water surface not greater
than the height of the channel banks.

b. F100dway conveyance capacity is the rate of dis-
charge in the overflow portion of the f100dway which
can pass through a specified area at depths and
velocities governed by the hydraulic dimensions of
the floodway.

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Designated Floodplain The area designated as a floodplain by official action
of the board of county commissioners or the city
council with the prior concurrence of the Colorado
Water Conservation Board.

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Detention The slowing, dampening, or attenuating of flows by
temporarily holding the water on a surface area, in
a storage basin, or within the storm or combined sewer
itself.

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Drainage Basin A part of the surface of the earth that is occupied by
a drainage system, which consists of a surface stream
or a body of impounded surface water together with all
tributary surface streams and bodies of impounded sur-
face wa ter.

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