FLOOD00374

• Designation Number: 146
• County: Chaffee
• Community: Unincorporated Chaffee County
• Stream Name: Lower South Arkansas River
• Title: Floodplain Information Report - Lower South Arkansas River
• Date: 4/1/1979
• Designation Date: 12/1/1979
• Floodplain - Doc Type: Floodplain Report/Masterplan

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CHAPTER I

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Purpose and Scope

INTRODUCTION

Therefore, upon official approval of this report by the Colorado
Water Conservation Board, the areas described as being within the 1%
*. d
chance flood (lOO-Year Flood) can be des1gnated as flood hazar areas
and their use regulated accordingly by the local agencies.

Authorization

This study was authorized by the Colorado Water Conservation Board

at the request of Chaffee County. Specific tasks were performed according

to the terms of the contract dated August 15, 1978, between the Colorado

Water Conservation Board and Water Resources Consultants, Inc.

The purpose of this study is to develop a planning tool that can be

used by Chaffee County to regulate the land use of areas within the flood-

plain of the South Arkansas River in order to minimize flood damages and

provide protection of both human life and property.

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The Colorado Water Conservation Board has the power and duty:

"...to dev.u.e. and 60ftmu..ia.te. me.thocL6, me.aM and p.f.an.6
6 Oft bftb!gblg about the. gfte.at:eJr. u.U.Uzation 06 the. uttte.M 06
the. M.a.te. and the. plte.ve.ntion 06 6.l00d dama.gu theJr.e.6ftom and
to du-i.gna.te. and appllove. -6toftm Oft 6.l00dWtllJ ftun066 ehanne.t6
Oft bcu>-i.n/.l, and to make. -6ueh du-i.gna.ti.on/.l ava..Uab.le. to .le.g.i.6-
.eative. bod-i.u 06 emu and un.i.neoftpofta.te.d tOWn/.l; to county
p.f.a.nn-i.ng eomm-iM-i.on/.l; and to bOalld-6 06 adjlUltme.nt6 06 emu;
-i.neOftpoftat:e.d town!.>; and eountiu 06 th.i.6 M.a.:te...."
as stated in Section 37-60-106(1)(c) of the Colorado Revised Statutes 1973.

The scope of the study includes:

1. Collecting available basic data related to this study from dif-

ferent sources including local, state, and federal agencies.

2, Conducting field surveys as needed to augment the basic data
already available.

The cities, incorporated towns, and counties within the study area may
provide zoning regulations:

3, Researching and documenting the history of significant flood

events that have occurred in the vicinity of the study area.

"...to uta.b.l.i.6h, fte.gu.t.a.te., ftUtJr.-i.c.t, and .umU -6ueh
u.6U on ~ft a1.ong any -6toftm Oft 6.l00dwa.teJr. ftun066 ehanne..l Oft
bcv...i.n, M .6Ueh -6toftm Oft MooduttteJr. ftun066 ehanne..l oft bMb!
hcu> be.e.n du-i.gnat:e.d and appltove.d by the. Co.lOftado wa-teJr. Con-
-6eJr.va..t.i.on BOalld, -i.n oftdeJr. to .lU-6e.n Oft avo.w the. haZaIlM to
pe.MOn/.l and damage. to pltopeJr.ty ftuu..iting 6ftom the. a.cc.umu..ia-
tion 06 -6toftm Oft 6-f.oodwa.teJr.-6..."

4, Performing hydrologic analysis to determine the peak rate of
runoff for the 10-, 50-, 100-, and 500-year frequency flood
discharges in the study reaches,

5. Performing hydraulic calculations within the study reach to

determine the water surface profiles for the 10-, 50-, 100-,

and 500-year frequency floods and to delineate the 100-year

flood in plan.

as stated in Section 30-28-111 for the county governments and Section 31-

23-201 for municipal governments of the Colorado Revised Statutes 1973.

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*

The terms "1% Chance Flood", "Intermediate Regional Flood", and "100-
Year Frequency Flood" can be used interchangeably as they are defined
by the same type of flood event (see Glossary), However, for consis-
tency, wherever possible the term "1% Chance Flood" will be used in
this report.

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