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<br />for development.
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<br />Therefore, the flood hazard to the co~~unity ~ill continue
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<br />the ",,~tc<~ays for vadous purposes but they <Ire small in ~l1"ntity and often
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<br />to Lncrease unless adequate floodplain regulations are adopted.
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<br />Cllrtail~d during high watH '.'[th th~ res"lt that tl",r~ Is" ~e,)igibie impact
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<br />Ob"t<uctlO1\" lo floodflo~ ~ithirl the study reach include natural "b_
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<br />o~ f loud p,,~ks.
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<br />structio~' ~uch a. <o<ok, brll~h and other ve~etation gro,"ing alan!'; the stream-
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<br />bank a'ld man ,"ade obstructio'ls s'-'ch a. bridges, building. and other features.
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<br />In the two !';ulche. wher~ flow carl occur in the road~ay, curb stops, mailboxes,
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<br />autOll\obile', ",all., f~ncea and other "Im1l&r feat\1reS become unintended flood-
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<br />f I"", ob~truction"_ Thes" obstructions Carl i"'p~d~ floodflo'" cau"ln~ condl-
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<br />t10ns that can rahe flood hcight~ '-'patre"", of the obnruction and i"crea.e
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<br />v~locltle~ do~n~trearn of thn obstruction.
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<br />Brush, barrels, proparl" tank~,
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<br />cribbing plank. and other debriS ean be carried dO"'l'\stream to eollent at
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<br />br1dge~ or other .tructure. cr~ating a da.'!Vtlin~ effecc arid o\'erbank flo",_
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<br />As floodflo~s Increase, mas.'es of d"brh may breH.k lo"~e H.nd C""S" a wall
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<br />of water and debris lo aur!l~ dmffiot<eam until another ob.trcoctiorl Is cn~
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<br />~"untH~d_
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<br />In sem.> in"ta"ee~, debri. 'MY collen to the point wher~ ~truc~
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<br />tural capacity 1" exceedcc and a bridgc i~ deotrcycd nr abutment" and
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<br />approachcs <>r"ded and n,,,db,,d~ d"""l\ed.
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<br />in th"alcoJy <each a particular
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<br />problem exi.t" with plu~gln~, by mobile stream bed ~aterial, wood and
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<br />otherdebri9,,,fthegratea,,,hich9HVe,,"ln\etstoth,,,"bsllrfacecon_
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<br />dulls on C1".s~ .."d Gre~ory r",lchea.
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<br />In ",ldi tion, b<'c.Hlse of ~he 10'"' base
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<br />flo~ in each. ,",ater",ay people have built structll,es. especially bridlles,
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<br />",hlch encroach on the channel ltself thereby runher reatric.!.t,,>\ this
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<br />floo<lflu,"capacilY.
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<br />n,~,'~ ..r~ no ~"ls"I,,~ 0< ."Hhori"~rl flood control structure'S In the
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<br />".,,,in ami n",,,, llnd,,< lnv,."ti~ali"n_
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<br />n",,,, "re some w,ltd dl\'ersions from
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