FLOOD09323

• County: Arapahoe
• Community: Arapahoe County
• Stream Name: Sand Creek, Cherry Creek
• Basin: South Platte
• Title: Floodplain Information Report
• Date: 4/1/1964
• Prepared For: Denver Regional Council of Governments
• Prepared By: US Army Corps of Engineers
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

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PLANNING FLOOD DAMAGE PREVENTION

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Where eonvereioo to open 6pBce use is fiot within the cepeeity of

GuiQelines for Use of Flood Plain Areae
F1QQd bistories Qelllonatrate that nature inai6ts 00 i t6 rights to the
flood pla111 and that the inQiv1Qual and the cOllllllunity cannot 19nore these
r1ghts w1thout peril. In its entirety, the flood plain haa varying degreee
of flood rillk. In the intere6'tofoptimUlllWle, itooybe impraeticalto
forego U8e of 811 parte of the flood p181n. However, it ie evident that
flood plain encroachmeot whieh red"e..s the hydr8ulic ef!'1e1ency of the
channel or the primary floodwllY 110 es to increlUe the flood h""'l'lrd to

the COllllllUDity to llchieve, flood-proofing of structllres 18 wsrrllnted to

minimize flood loeeee. These rnee6ures may 111clude "dequa~e structllrlll

etabllity to withstand floods, ~n18nent closure of low- level o~ntngs

with ~"OllrY, relocetion or flood-proofing o~ machinery, electriesl

e<l.'.>.1P'llentand11lventoryebovetheprobablefloodelevatioll,8ndpro-
vieions for "atertight closures of doorwaye by bulkhesds, "ewer8 by
vslves, etc.

CONCLUSIONS

other property is likely to be egl'linst the cODlllon gQQd, alld thUll eubject
to public regu18tion.

It i6 evident that encroechlllent into flQQd hazard areae occurs

'IhI! public intereet requires pr1m8rlly th8t encroschlllent of the
ch8nllelit8elf should be prohibited. The degree to "hich encroachment
of the flood plain ahould be prohibited in the public intere6t dependB
On the ~hsrscterieti~e o~ the flood plain IInd. the n8ture of" potentiel

partially through laek Of knOW"ledge of flooding potentials alld partially
through a belief that the risk of flooding is " threat of no l.mmO!d18te

1IIlportance. Increllsing urban flood damages demonstrate th8t both lack

of information 8nd lack of concern CSlI inflict IleriOU8 eoonomic p"n81ties.
From an economic standpoint, three choices sre available to the

Thc risk 0::: da:::3gellin t~o flood. .,lll~ rll::J.ge 1':::00; the reI>Cated deo:agca

cOIlllllWlity: (1) Endure flood 10S8e6 58 the pr1ee for use of the flood
pl81n; (2) COlletruct flood control 1rnprovement8 to eliminete the flQod
threell; or (3) Uee the flood plain only as WlIrrented by a prudent regarQ
for flooding potentials.

encroachments.

or frequent floods to the remote but potentislly catestrophic delll8ges of
th8 greater prOb8ble flood. flow-ever, in weighing the prudenee of 1100d
plain occupanee, it must be borne in mind that the relative infrequency
o~ the lsrger floode eonveys no eesurallce eg8illst their occurrence in the

r.e..rt."t.u-... FortLliIre<lIiu.<:l, .loo:J.loatlo11oi 1I1111lu.l" ",,1>j..d tuflooJ.

The public'e choice s~ theae alternat1ves ie not sl"aya limple,
eioce: (1) Use 01 portione of the flood plain can 8ggravate the flood
problems of other portiOllS aod. thus vio18te the cOllIIIIon good; (2) The

h8zard to open spsce cOIlIIllunity use vith smaller damage potentials, 6uch
Be parks end pllrking lots, hlllI tho advantage o~ COllllIHmity u.ae of flood
p18ill land~ v1thout the risk of c8tsetrophic economic damages.

COlt 01 the u,provelll/!llh requlredtoechiev/!8dequate control of flooda

llIay exceed the amount o~ preventable damagea. Moreover, the public lllSy
be UIlWilling to beer the coet of iIlproveOleote unleu the cooznongood iB
eurf1cient to jUltify cor.ection of the problem at public expenee; end

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