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

PASTFLOOOS

of intense precipit~tion and projectIon of Sj~rm movement gives
some le~d tIme for flash flood warnIngs; this inform~tlon is
promptly dlsserniMted to ~II news """dla and local offlcl~ls by
the best cornmunlc~tions ~v~ll~ble.

SUl+lARY OF HISTORICAL FLOODS
Large flood discharges have occurred In the studY reaCh
of the 81g Thompson River and the Little Thompson River. Tables
3,4,and 5 showdah collected "t thegllglng shtlonsoperlltedby
the U. S. GeologlclIl Survey IOCllted lit the mouth of the canyon east
of Orllke and 4 miles west of La SlIlle on the Big Thompson River
and at the stlltlon locllted 7.5 miles southwest of Berthoud on the
Little Thompson River.

Flood flqhtinq and emerqency evacuation plans - The
Larimer County and Boulder County Civil Defense Offices coordinate
disaster activities with the State Civil Defense Office. They feel
that they have adequate organization to meet any emergency.

Material storaoe on the flood plein - Floatable manmade
materiel stored on the flood plain Is often waShed away during
floods with the potential of collecting at points downstream. The
floodplain In the study reach is relatively clear of suchmateri<'l!s .
When floatable objects are stored on the flood plain, they should
be secured in some faShion. Other floatable material, Such as
trees, branChes, brUSh, and logs, Is In evidence along the rivers.
This material could form obstructions to floodflows, especially at
bridges, In the event of a flood.

TlIble 3
Annual Peak olsChargesll for t)e Big Thompson River
flearOrak4

DlIte
.
, J., 1906
.
So, ''''
22 Joe 19.41
, Jun 1942
" J., 1945
" J.. 1947
, J.. 1949
.
3 ,., 1951
"'" 1957
" J.. 1965
" J., 1976

Olschllr!'le
(c.f.s,l

6,000

5,600
4,690
3,730
7,600
2,320
3,BO

3,530
2,040
2,220
31,200 (estlmetedl

1!

2/

Only those yellrs hllvlng e peak dlsCh<'lrge of 2,000 c.f.s. or
grellter lira lndlclIted.
From U.S.G.S. GlIg1ng Station lit mouth of clInyon, ~OO feet up-
str..arn frcw.HlIndv01tchdl"ersiondlltl\and6mllesellstol Drllke.
Not a continuous record.

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