FLOOD08336

• County: Chaffee
• Community: Poncha Springs, Salida
• Stream Name: South Arkansas River
• Basin: Arkansas
• Title: Floodplain Information Report - Lower South Arkansas River
• Date: 4/1/1979
• Prepared For: Chaffee County
• Prepared By: WRC Engineering, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Aspect

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Backwater Effect

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Channe 1

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Cloudburst

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Correlation

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Confluence

Conveyance Capacity

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Designated Floodplain

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Detention

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Drainage Basin

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GLOSSARY

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Flood

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

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The rise
upstream
of flow.

in surface elevation
from and as a result

of flowing water
of an obstruction

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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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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.

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

that
and
strong

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Flood, 1% Chance

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A point where two or more streams meet.

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. Floodway conveyance capacity is the rate of di~-
charge in the overflow portion of the floodway wh~ch
can pass through a specified area ~t d:pths.and
velocities governed by the hydraul~c d~mens~ons of
the floodway.

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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Flood Frequency

Flood Peak

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Floodplain

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Flood Profile

The slowing, dampening, or attenuating of flows b~
temporarily holding the water on a surface a:ea, ~n
a storage basin, or within the storm or comb~ned sewer
itself.

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A part of the surface of the earth that is occupied by
a drainage system, which consists of a surface ~tream
or a body of impounded surface water together w~th all
tributary surface streams and bodies of impounded sur-
face water.

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An overflow on lands not normally covered by water
which are used or usable by man. Floods have two
essential characteristics: (1) The inundation of
land is temporary. (2) the land is adjacent to
and inundated by overflow from a river or stream
or an ocean, lake or other body of standing water.

Normally, a flood is considered as any temporary
rise in streamflow or stage, but not the ponding of
surface water which results in significant adverse
effects in the vicinity. Adverse effects may include
damages from overflow of land areas, temporary back-
water effects in sewers and local drainage channels,
creation of unsanitary conditions or other unfavor-
able situations by deposition of materials in stream
channels during flood recessions, use of ground
water coincident with increased streamflow and other
problems.

A type of flood, including the water surface elevation
and territorial occupation thereof, which can be
expected to occur at any time in a given area based
upon recorded historical precipitation and other valid
data, but with an average statistical one percent
chance of being equalled or exceeded during anyone
year. The term is used interchangeably with lOO-year
flood or Intermediate Regional Flood.

(See Probability) The average recurrence interval of
specific discharges or water stages which cause flooding.

The maximum instantaneous discharge of a flood at a
given location. It usually occurs at or near the time
of the flood crest.

An area in and adjacent to a stream which is subject
to flooding as a result of the occurrence of a 1% Chance
Flood. Thus it is so adverse to past, current, or fore-
seeable construction or land use as to constitute a
significant hazard to public health and safety or to
property.

A graph showing the relationship of water surface
elevation to location, the latter generally expressed
as a distance above the mouth for a stream of water
flowing in an open channel. It is generally drawn to
show the surface elevation for the crest of a specific
flood, but may be prepared for the conditions at a
given time or stage.

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