FLOOD09306

• Designation Number: 204
• County: Larimer
• Community: Fort Collins
• Stream Name: Spring Creek
• Basin: South Platte
• Title: Major Drainageway Planning - Spring Creek, Fort Collins, Larimer County, Colorado
• Date: 8/1/1980
• Designation Date: 1/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

Addi tional information on the flood Insurance Program is a~ai l<1ble from 10c<l1 insur-

Federal Insurance Administration
Building 710
OenverFederal Center
Lakewood, CO 80225
[phone]

Once property damages were evaluated, the different alternatives were tailored to
alleviate areas experiencing the greatest flood damage. The design altenlatives
studied for the most part were the least expensive in terms of cOllstrudion itnd

ance agents or brokers and the:

implerr~ntdtion costs ,Ihile meeting the objectives of tM project. The five al-
ternative improvement designs considered are described below.

IMPROVEMENT AlTERNATIVES

Initially, feasiblealternativedesignswereidentifiedtoalleviatefloodingin
each of the 9 reaches. Using potential ddlMge information and a cursory review of
the practicality and cost of improvements, many of the alternatives were eliminated.

For this study, fi ve basin al ternati~e impro~ement designs were evaluated. For
simplicity in discussion, the Iline previous reaches were grouped into three larger

reaches:

GroupA-Confluencewith theCacheLaPoudre River upstream to Stove rStreet
(Reathes1,2&3)

GroupS

Stover Street upstream to Shields Street (Reaches 4,5&6)

The remaining alternatives for each reach were then combined into 5 alternative
plans for detailed benefit-cost analyses. These alternatives are as follows.

Groupe Shields Street to the upstream limit of Stuc!y (Reacl1es 7,8&9)

1l1lprovelllentaltefflatives were developed for each of the nine rea chesscparatelYJnd

Altemative ~l

1"p"",v'''"",,,t ~lt""n~tiv"~ wpr" ..Y~mi","<1 for "M'll gr'Hlp (Hll.\" ;n <1f'vf'lnped areas where

Alternative #1 is the adoption ofa floodplain management progrdmfor the Spring
CreekdrdinagewdY. Tile intent of the program would be to guide and regulate future
f1oodplaindevelopc;lentalongSpringCreek,dndtQevefltual1yprovideatloodway
channel,free from obstruction, to convey the l00-yeareventthro ughtl1eco!Tlllunity
\/ithminir.>aldamage.

are referred to in the Technical Addendulfl.

drlmac;esaccur. In undeveloped areas, a floodpldinmanagementprogralllwouldgover n

fllturc developrn€nt and would limit damages due to flooding.

In our an~lysi,;, danlagl'S cduwd by flooding associated with a fully developed basin,

This floodplain managec.l!'nt program is thcnonstructural awrcdLh to floodplain im-

strea~ detention and canal i~'Partati(ln (i.p. rl(>Ildi~'} hphj~rl T~ft l1il1 II'Md, at thp

provenJel1t, and damage mitigation.

Colorado ~ Southern R~i1ro~d, etc.) were used for developing the da~~ge curv~s in

this study. However, i mp.ro~ement a Hernati ~es were somet imes des i gned for two fl ow

The floodpld in man.l~e'Tlent ~lternati 1'1' \tould incl ude the tol1owing:

cQnd it i on~ (with deten t i on ,1I1d withQut detent i 01'\). For e~ch oj: He rnat i VI', the benefit:

1.

Adoptiolluf lh"IOO-year flood event for fu11y developedbasill c on:litions

cost ratio is foot~oted to int,iLdte whether impro,c~~nt5 correspond to the detained

dnd c~n~l importation JS the regulalory flood event.

or lhe ur)det~ ined flow.

>
.'

Restrict ;011 or a 11 de,('lop"",nt ill the floo~'lay Jreas as ident itiec in lhis

report aM as modi fied in Tdlll~ 14. Th is floodway is based upon the cr'i-
trrion nf ('lU:r(l~cr.mel1t upon the floodplain untl1 a O.S foot dse in the

~ 4? -

'8-