FLOOD01761

• Designation Number: 83
• County: Larimer
• Community: Unincorporated Larimer County
• Stream Name: Big Thompson River
• Title: Floodplain Information Report - Big Thompson River, Loveland to the Larimer-Weld County Line, CO, and the Little Thompson River, Boulder and Larimer Counties, CO
• Date: 6/1/1977
• Designation Date: 11/1/1977
• Floodplain - Doc Type: Floodplain Report/Masterplan

GLOSSARY OF TERMS

it Is generally dra~n to show surfa~e elevetlon for the crest of
a speclflc flood, but may be prepared for condlttons at a given
time or stage.

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An oVerflo~ on lands not normally covered by water end
that are used or uSable by men. Floods have two essentIal char-
acteristics: {I)thelnundlltionof lend Is temporary; and (21
the land Is adjacent to and Inundated by overflow from II river,
stream, an oceen, a Illke, or other body of standIng water.

Flood Stage
The stage or elevation at Which overflow of the natural
banks of a sfream or body of water begins In the rea~h or area
In which the elevation Is measured.

Normally a flood Is considered as eny temporary rise In
streamflow or stage, but not the pondlng of surface water, that
results In sIgnifIcant adverse effects In the vIcinity. Adverse
effects ~y include demeges from overflow of land areas, tempor-
ary backwater effects In sewers and local draInage channels,
creetlon of unsanitary conditions or other unfavorable situations
by deposition of materIals In stream Channels during flood reces-
sions, rise of ground water Coincident with Increased streamflow,
and other problems.

HiladLoss

The effact of obstructIons, such as narrow brIdge open-
Ings or buIldIngs, thet limIt the area through which water must
Ilow, raising the surface of the water upstream from the obstruc-
tion.

Left Bank

The bank On the left side of a rIver, stream, or water
courselooklngoownstream.

Flood Crest
The maximum stage or elevation reached by the weters of
a flood at a given locatIon.

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Reference Point
A numbered point Identifying e specific location used
for correlating the data shown In various forms throughout the
report.

FloodPlain
The relatively flat area or low fands adjoining the
chenneIOlerlver,stream,wetercourse.ocean,leke.orother
body of standing water which haS been or may be covered by flood-
water.

RI!lhtBank

The b~nk on the right sIde of a river, stream, or water
course looking downstream.

FI<>ooPr"fll..
A graph showing the relationship of water surface ele-
vation to location, the latter generally expressed as distance
above mouth for a stream of weter flowing in an open channel.

10-,50-, 10Q-, and 500-VearFlood
A flood havinQ a 10. 2. I. or .2 percent probabIlity,
respectively, of occurrence In any year or an everage frequency
of occurrence In the order of once In 10,50. 100, or 500 years,
respectIvely. The f loed may occur In any ye~r. I t Is based on

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