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<br />I <br /> <br />March 2:3, 1990 Dn,ft Heport .- FOR REVIEW ONLY <br /> <br />:llr:pCtS~E.'d rt?bni Iding mor'2tDria aftf::f' lendsJ.idt? and mudflt;~v d:H.;aEters (t<ockt:~lman~l <br />1986) . <br /> <br />.g,:~D_Jlfli:.~.fL.r:p,!;!n:tY..'!. CA 1 imi 1.:5 developrnl?IJt 011 unstable slopes to onE' LOTi ~ per 4.0 <br />BCrt:'t~l and n0quires a site investigatj,on to E\nSUre safe devf210pmemt at thf~ lDW <br />density (Kockelman, 1986)6 <br /> <br />~H:~t1j~P.b!ILtY"._.JJT is cOllsidering adop,t.iori of an o~-dinance which w'':lJJld require a <br />detailed Natl.tJ-al Hflzards Assessment by a registerE\d prof'p.sEjOl1a} !~c:'cdogjst; foy' <br />!!E'IE:'f"'y' applicatiDn to use land~ grade, construct, Dr other~~,lise devl:"'?lop 'in the <br />NHO 2:r.>nE-:: (Natural HaZanJ!:!f R2\det'J Ovel~ Ja.y Zernf:.']" u nil &):cept for E.truc't.ures nc~t <br />occl!pi~d by' humans. Critical facilities, water tanks, reservoirs:. and c:::;nals <br />mll~::t have an assessment: Nhich includes engineered plans for c:cnE.tructiCl\ln <br />Btruc:~ur.es slIbjp-ct to debris flcq~~ hazards must be!l pro't,S'c:i;ed by a <br />dcfh~c:tjon berm or' debris ci::,t.chment b~:!5in ~ a" which is eng:ineETed to pn?vr:nt <br />the entry of a flow haviI1q a Dne percent chance elf DCClrrren~::E.\ in any calendar <br />YC:'iU' as determined by thEl 1\Ia.hrraJ Hazi.-'trd!:', Assessment'; (lr' the Etructun? is. <br />eng 1. flc(yred to resi st entry at any pDi nt in the path of the fl(t~',l up to an <br />E'qu1.vaJent fluid prel:.;5Ure lClad of lCl,6L:O N/m:9H. The NHO iil>::ludes debr'is flcll..\l <br />J~rr:ra!::'1 al]l1vjal fans susceptible to debris flDl-'J d(2pt)sition and ffioHntainnllS <br />an:-3S ~>J i t:h '2-1opes greater than 3CW (Utah Count.y ~ 1989). The scope c)f the study <br />ffii3Y include Uk/bison, J98('1): <br /> <br />Debris flow potential of the drainage basin; <br />DE.1bris flc!\>\l potential c.~f the stn?e'7lm I:harmel; <br />Analysi~,* elf man-"m~1de structures in t.he dl-ainage basin; and <br />Recommendations for mitiqa'tion of the dt~bri5 flm"J hazardn <br /> <br />In t.tr!t,,,.Gtt:L:.-.~:,f._Y?n!.H1:,a'L-b:B., soil=:. and geology reports are requi.red if: ::1 ell"!; Of <br />fi 11 great~r th~n th,f2e feet deep i. s rElqui reti; the fi.1] ) s t.o slIppor 1; <br />structural footings; (H' an eng.1nee-red cut tt)- fill i:-, )~equired" If'! addition, an <br />engineel-jng geolngy j-epc)rt is required if: fi.:nish cut or- "f:i.J J fclc(?s arG\ <br />proposed wit.h vertical heii]hts greater than 10 feet; (If where (~)dst:,ing SlOpE?'::' <br />me gr.ater than 10 hDrizontal to 1 vertical IFEMA, 1987). <br /> <br />In tb,~:!."J~1i.x:.,.-.f;~,L"lib.tt:.t~~L_..~~e., de",/elopment: plans in area!-) design~ted 3:, Z{)nE~ t'1 0/1 <br />t;he Flood Insurance Rate Map (FIRM) ml\5t inclu<..ie~ a E:,t.dJs E'ngjnf,~c';\rjn9 and <br />getllD'.~Y repcq..t; siting, orierlt:atir.1)l and design tel minimize mudflcH'1 dBmage; <br />accommodation of debris ane! prnviE-ions for clean up and remova];; i::'tnd <br />ac:cD/1HrtodE\t ionS'! fr.:q- the conv'cY2:rilce of thp 1(h)-'year mudflctl.-'J Cq- a debr i 5;, ba!::.i n <br />deEi<]D!0d to contain the lOO-'year mur;lfloVJ IFE!1A, .1.987).. <br /> <br />Recommendations for ManaQement Credit: <br /> <br />(NOTE, THE CREDIT <br />ACCOROING TO THE <br />O\lEF<AI.. L SCClR J MG.. ] <br /> <br />POINTS RECOM~;FNDfD BELm,) WILL BE i'\DJLlSTFD AT ~l I ATER DATE <br />RELATIVE I NPORTANCE OF SPECI,;L HAZARDS ~1<')r,'~GEt'lENT IN THE <br /> <br />2~ 1 ~ <br /> <br />The fn"esC'l"vatiell) of open <br />designat.:t?d muclfloltJ hazard <br />He t:i \Ii t:.y' 420 - Open SpaCE? <br /> <br />spacr.;;l and <br />c"t)"t::a~:. kJould <br />PresE!Tv8.tion~ <br /> <br />enforced <br />f'ecf;~i VI? <br /> <br />lm.J dens:i t:y 2D{il'(JQ in <br />SHOS e.nd SHi.L t:rr::,dit in <br /> <br />NF-'7 <br />