FLOOD08504

• County: El Paso
• Community: Calhan
• Stream Name: Calhan area rivers and streams
• Basin: Arkansas
• Title: Floodplain Management Study
• Date: 8/1/1995
• Prepared For: Calhan
• Prepared By: USDA
• Floodplain - Doc Type: Floodplain Report/Masterplan

GtOSSARY OF TERMS
CHANNEL - A nacural or artificial water course of perceptible
extent with definite banks to CQnfine and conduct continuously
or periodically flowing water. Channel flow is that water
which is flowing within the limits of the'defined channel.
FLOOD - Water from river. stream, water course, lake or other
body of standing water, that temporarily overflows the
boundaries within which it is ordinarily confined.
FLOOO CREST - The maximum stage or elevation reached by the
waters of a flood at a given location.
FLOOD FREQUENCY - A means of expressing' the probability of flood
occurrences as determined from statistical analysis of
representative stream flow or rainfall and runoff records.
The frequency of a particular stage or discharge is usually
expressed as occurring once in a specified number of years.
The 10-, SO-, 100-, and SOO-year frequencYd flOO,ds hav~ anh
average frequency of occurrence in the or er 0 once 1n t e
number of years indicated.
FLOOD HAZARD AREAS _ Areas susceptible to flood damage.
FLOOD PEAK - ~he highest stage or discharge attained during a
flood event; also referred to as peak stage or peak discharge.
FLOOD PLAIN - ~he relatively flat or lowland area adjoining a
river, stream, watercourse, lake, or other body of water which
has been or may be covered temporarily by flood water. For
a~~inistrative purposes the flood plain may be defined as the
area that would be inundated by the 100-year flood.
LEFT or RIGHT STREAM SANK - The left or right bank of the stream
looking downstream.
PERCHED CHANNEL FLOW - A condition where the flow elevation in
the outer portions of the flood plain is higher than the flow
elevation in the main channel. This condition occurs when a
secondary channel receives inflow from aome location upstream
and maintains a flatter slope then the main channel.
REACH - A hydraulic engineering term used to describe
longitudinal segments of a stream or river.
RUNOFF - That part of precipitation, as well as any oth7r flow
contributions, which appears in surface streams of elther
perennial or intermittent form.
S~~ - Any natural channel or depression through which water
flows whether continuously. or intermittently, including

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modification of the natural channel or depression.
STRUCTURE - Anything constructed or erected, the use of which
requires a more or less permanent location on or in the
ground. Includes but is not limited to bridges, buildings,
canals, dams, ditches, diversions, irrigaeion systems, pumps,
pipelines, railroads, roads, sewage disposal systems,
underground conduits, water supply syseems and wells.
VALLEY CROSS SECTION - A plotting of the topography of a seream
channel and adjoining landscape as viewed perpendicular to the
flow in a downstream direction. The ploceing represents a
specified location within a designated stream reach.

WATER SURFACE PROFILE (or FLOOD PROFILE) _ A graph showing ehe
longitudinal relationship of the water surface elevation of a
flood event to location along a stream or river.

WATERSHED - A drainage basin or area which contributes to runoff
and transmits ies usually by means of streams tributaries to
the outlet of the basin.