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<br />of$I,OOO per year for material cosls should be budgeted formaterialcosts,~'ssumingthat
<br />periodk replacement of short sections of fences, riprap, and other emsion control
<br />measures will be required,
<br />
<br />condition, Flood damage to property is a function of the type ofpropcrty, property value ,
<br />replacement C(1st, vclocily of flood flow, amI the depth of fl()(xlwatcr, Depth of
<br />/loodwatcr m each building. or groups ofhuildinf,\s was calculated forvanous frequl;mCY
<br />events, Calculated flood depths wcre increased by velocity hcad to accoum for the flood
<br />/low velocity etfect. No records of the vaJuc of building eontcnts are available, and the
<br />contents of buildings are therefore estimated to be either 30 pereent Oflh evalueofthe
<br />structure (residential) or 50 pefeent (commereial). Damages to bridges, culverts, and
<br />tlumes were not assumed unless the flood water levels exceed the lOp of tbe waterway
<br />opening. Structureswcre assumed 10 be lost at a damage valuccqual to their present
<br />estimated replacement cost. Direct flood damage to ,vater, sewer, gas, electrical and
<br />telephonc lines was estimated from City maps. Erosion damage along the waterways and
<br />dean-"p ~0:;tS f"lIowing a flood were estimated to be a function of waterway reach
<br />length. Erosion damag~ ~'ld clean-up costs were assigned only to improved channels, not
<br />to unimproved channel rca,,::~~. Crop damage was assumed to be the value of onc
<br />~eason's production. Based on di,'('llssi"n< with the Department of Agriculture. it was
<br />as~umed that the average production value per acre 101 :,-;,--;:-:!:...-:;; ;;-; t:,~ ?"W(lee Creek
<br />drainage basin i,; S500/acre. Direct damage for the City of Sterling wa~ taken from the
<br />Flood Plain Information and Drainage Plan prepared in May 1983 by Leafand Resource
<br />COllSultallts. This report was the busi, for the current FIR.\1 mapping for the City.
<br />O,unage ttgUl"C. -.;c~~ updated using inflation figures from the Colorado Department of
<br />Revenue.
<br />
<br />Frcqu<,>nC}' andSeverit}'ofFlood Ev<,>nls
<br />
<br />As discussed in Section Ill, this area of Lngan County and the City of Sterling has been
<br />subjocted to severe Hooding from Pawnee Creek and the Pa'Wflee Creek o"<:rl1ow on at
<br />lcastthreeoceasionsineludingI935,1965andJulyofI997,andmorefrequent but less
<br />damaging lower flows. The 1997 storm is estimated to have eaus.:d between $10 to $12
<br />million in damage along the lowcr Pa'Wflee Creek, To'Wfl of Atwood, and Pawnee Creek
<br />overflow area. Damage CellOty wide from this event was even greater. Based on a
<br />gtaphiealplottingofpeaklloodllowsfrompteviousflDodplainstudiesalld an estimated
<br />flow of 3800 efs at the Cemetery (provided by CWeB based upon high water marks), it
<br />isapparenllbatthe ]997 [lood was approximatcly thc 7S-)'ear,tonn at this location.
<br />
<br />Estimated D,)lIar Amuunt of Damages Prevented
<br />
<br />!'Jood damages include direct damage to buildings m>d e,llllents, damages to road,; and
<br />bridges, and several torms of indirect damages, In the case of tbe Pawnee Creek
<br />overflow, buildings subject to dnmage include both residential and eommcrdaJ.
<br />Significant damage to crop lands can also result Ii-DOl flooding. Examples of indir\:Ct
<br />damages include: Loss of salcs; removal of dehris; damage to public I:tilitie~; and loss of
<br />renti,]s.
<br />
<br />l. L"S'ofUfe
<br />
<br />Indirect Damages: Indirect damaf!es include thc ~~i"c ur iv,,; ::;..:~i)1ess and services; and
<br />tbe c~;t~{at;,'vi:\ling hardsbips, safeguarding health. rerouling traffic, delay. ;;,~~ ;~lMed
<br />phenomena. and the loss of sale, taxe~. The monetary value uf indirect damages (.Oannol
<br />beestimatedas....'ClIasthoseofdirectdamagcsbceauS<)ofthelackofsuflicientdamage
<br />data, 'These damages, e:.d'.:d~ng lbe IUSS v; <qks mxes, were estimated as a fraction of
<br />direct damages following estimates used by the US Corps 01 r.ngineers. Local <<l::! Sml~
<br />sales taxes are lost in commercial areas u' a result ofbll,ine$'; disruption caused hy
<br />/loods, Tax losses wcte taken to be 5 percent Dftbe eommcreial dircet lost.
<br />
<br />Five ca!cgories offlo()d damages were estimated, as follows:
<br />
<br />2, DircetDamages
<br />
<br />3. Inditect Damages, Including LossofSalcsTax
<br />
<br />Secondury Oam,!&~: Secondary damages arc those damages, which occur outside of the
<br />immediate flood ".OneS due to reliance nn some output produccd by the damaged property
<br />or supplied by some hindered services. No monetary values were as,igned to lhe
<br />secondary damage in tbis study sincc normall)' thc secondary damages tend 10 he offset
<br />by secondary benefits.
<br />
<br />4. SeconduryDamages
<br />
<br />5.lntanglbleD"mages
<br />
<br />I.ossofl.ite: 1,0ssoflileiseonsideredunlikelvundertheIOO-veartloodeondition,
<br />. .
<br />hccause the dcpth of inundation isscldom more than 5 feet and the rise of water level
<br />would be gradual enough tor almosl anyone tll reach safety during a flood. Drainage
<br />wavsare always pOlent;al hil;,lrds. and possihle Ins< orlif,'may in t;1et OCellr, hm for
<br />purposes of this analysis, no loss of life was considered.
<br />
<br />Intangible Dumi!~: lnt;mgiblc damages includc such categories as cnvimnmcnlal
<br />quality, social well heing, and aesthctic values. Asthcirnamcimplies.itiscurrentlynot
<br />russiblc to Itc'curately estimate monetary values of int;mgible damages. I!owever, the
<br />impact of these damages, as social pmbkms in a community face.! with a major fl,x)d,
<br />a.c ;~;ll. For p<i'lJOSC.> 0(":'[;;.> rqxxi,.hi oidd;ti""", l;'.~ l-'C,wllL 0[,,11 OUj~1 Ja.Jj1dgc~ v,c,c
<br />added to cover intangible damages. The tollowing tahle pr~sent,; a summa!) of other
<br />Jmnagcs <IS a Ilcrccntagc ofJirect Jalllagcs, Forpurpo,;e;ofthi~allalysis.otherJltmagcs
<br />'l'crecol1sidercdtoa\'erage20%ofdireetdamages,
<br />
<br />Oircet Oam;l~: Din.'Ct damages comprise the largest damage category and Ihey call be
<br />cXl're~scd in llIonetary value, with" r"ir u~gret' l'f al.cumcy, In ur",," af>.'i~'. dlrl."c-(
<br />damages occur primarily to buildings and to public facilities such as bridges, mad.s,
<br />utilities. and rclatcd facililics, Ruml areas direct damage relates primarily 10 loss of
<br />crops, loss (lfuut.buildings. cleanup. and work required to retum fields to usable
<br />
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