FLOOD09461

• County: Weld
• Community: Weld-Big Thompson
• Stream Name: Big Thompson River
• Basin: South Platte
• Title: Weld - Big Thompson Community File
• Date: 1/1/2001
• Prepared For: CWCB
• Prepared By: CWCB
• Floodplain - Doc Type: Community File

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Mr. Chuck Guy
May 9, 1975
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colorado communities, to qualify the communities for the regular
flood insurance progrwl. These studies are presently on-going
within our office. The studies include detailed flood plain
delineations and approximate delineations on over 300 miles of
streams l1i thin the State.

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f'hortly, ~'e viII be undertaking fl flood plain delineation project
for the Colorado Water Conservation Board in which nel" State
flood plain delineation guidelines and report formflt will be
utilized. The auidelines developed by the Water Conservation
Board are just recently completed and should be used as the
basis for reporting the results of the flood plain investiga-
tion on the Pi" Thompson.

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In addition to the studies, pla.nninrr anc1 design projects 1,.8 have
completed for the Federal, State and local flood control agencies
named above, we have also worked extensively for local qovern~ent
and private concerns. Our firm ha.s completed a very thorough
flood~lay delineation on Foulder ('reek for the City of Boulder.
Pc have completed a combination structural, non-structural Haster
Plan for Slaughterhouse Gulch in Littleton and have also com-
pleted preliluinar'1 cJrl'J.inageway design on streams ~li thin the
'1'011 Gate Creek Basin in l\urora.

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Decause of the impact of flood plain elelineation on adjoining
properties, it is mandatory that any studies and conclusions
be based on factual information which has been detennined from
up to date technoloay, methods, and procedures. The importa.nce
of such work is evident from the need for passing federal legis-
lation establishing the flood insurance progr=, as l~el1 as
Fouse nill 1041 in the Colorado Legislature. ~o conform with
the detail and accuracy requirer;1ents of such an investigation,
.Ie utilized up to date hydrolo(fic methods accepted by all
Federal agencies I'IS well.as State and local agencies. Nost of
the methoas have been computerized to follow accepted procedures.
~Te have developed computer programs to conforI11 with the Colorado
Urban Hydrograph proceclure of the Urbeln Drainage & Flood Control
District, as well I'IS the Uniform Technique for Detemining Flood
Flow Frequencies, developed by the Federal Water Pesources
Council and also a hydrograph package for unit and storm hydro-
graph determination and hyc1rograph routin<J, developed by the
Corps of Engineers', . Hydrologic T:'ngineerj.na Center in Davis,
California. :rC'r flood hydri'l.ulics, l.;e utilized the Corps of
Engineers BEC-II Water Surface Profiles eompue~r program, also
developed hy the Corps at .the Hydrologic Pngineering Center in
Davis. This program is accepted nationally as an accurate
means of defining flood plain limits.

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