FLOOD06258

• Designation Number: 25
• County: Mesa
• Community: Grand Junction
• Basin: Colorado Mainstem
• Title: Floodplain Information Report - Colorado and Gunnison River, Grand Junction, Colorado
• Date: 3/1/1973
• Designation Date: 10/1/1973
• Floodplain - Doc Type: Floodplain Report/Masterplan

GLOSSARY

Backwater Effect. The rise In surface elevation of flowing water
upstream from and as a result of an obstruction to flow.

Cloudburst. See "thunderstorm."

Flood. An overflow of water onto lands used or usable by man and
not normally covered by water. Floods have two essential character-
istics: the Inundation of land Is temporary; and the land Is adjacent
to and inundated by overflow from a river, stream, lake, or ocean.

Normally, a "flood" Is considered as any temporary rise In stream-
flow or stage (but not the ponding of surface water) that results In
significant adverse effects in the vicinity. Adverse effects may in-
clude damages from overflow of land areas, temporary backwater effects
in sewers and local drainage channels, creation of unsanitary conditions
or other unfavorable situations by deposition of materials coincident
with increased streamflow, and other problems.

Flood Peak. The maximum instantaneous discharge of a flood at a
<:Jlven location. It usually occurs at or near the time of the flood
crest, the maximum stage or elevation reached by the floodflow.

Flood Plain. The relatively flat area or lowlands adjoining a
river, stream, watercourse, ocean, or lake, which have been or may be
covered by floodwater.

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Flood Profil e. A graph show I n'1 the re I at i onsh i p of water surface
elevation to location, the latter generally expressed as distance above
mouth for a stream of water flowing in an open channel. It Is generally
. drawn to show surface elevation for the crest of a specific flood, but
may be prepared for conditIons at a given tIme or stage.

Flood Stage. The elevation at which overflow of the natural banks
of a stream or body of water begins In the reach or area In which the
elevation is measured.

Fl oodway. ThE' channel of the stream and that port ion of the flood
plain that would be used to carry floodflows.

Intermediate Regional Flood.
of occurrence in the order of once
occur in any year.

A flood having an average frequency
In 100 years although the flood may

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Standard ProjE!ct Flood. The f I cod that may be expected from the
most severe combination of meteorological and hydrological conditions
that are cons i dered reasonab I y character I st Ic of the '1oo<:Jraph lea I area
in which the dralnac:e basin is located, excludlnc: extremely rare
combinations.

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