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<br /> <br /> <br />Single LoVStructure Protection <br /> <br />Elevation on properly designed foundations (piles, col- <br />umns or armored fill) <br /> <br />Floodwalls and berms <br /> <br />Reinforcement of uphill walls, windows and doors against <br />debris impact <br /> <br />Design Consid6rations: These measures are most cost. <br />effectively implemented at low development densities, but <br />should be considered for all structures on fans. Owners of <br />existing structures should consider retrofitting their homes to <br />protect against future flood hazards; new lots should be <br />planned with adequate open space to accommodate flow <br />paths. Velocity/scour, sedimentation and debris impact must <br />be addressed in the design of elevated foundations and of <br />floodwalls. Floodwalls should not be solely relied upon for <br />protection, but as a suppiement to elevated foundations. <br />These measures are usually financed by the homeowner. <br /> <br /> <br />Figu,. 16. <br />This hom9 In Palm Dault, California has bHn ahlVatlKl on fill. Utilltl.. <br />(shown agalns' th. left sid. of ,,.. houu) IYv. .'so biNn raistHJ to <br />minimas potsntial flood damags. <br /> <br />The choice of the appropriate measure(s) will uttimately de- <br />pend upon the community's development plan and the level <br />and extent of protection desired. <br /> <br />10 <br /> <br />What Factors Shoutd Bo Consldored Whon Building On A <br />Single Lot? <br /> <br />tt is recommended that single lot deveiopment only proceed <br />w~hin the framework of a comprehensive plan for the alluvial <br />fan, which has Identtlied the fan's flood hazards, design <br />requirements for the safe construction of individual s~es, and <br />how each site would m into a coordinated approach. If such a <br />comprehensive plan has not been developed, then the follow- <br />ing general steps should be undertaken to minimize the <br />potential flood risk for any proposed structure: <br /> <br />1. AVOID THE MOST HAZARDOUS AREAS OF THE <br />FAN. <br /> <br />2. Consult with local planning, building, and engineering <br />officials to discuss the potential hazards specific to the <br />site, regulations in effect which would specify methods <br />of construction, and any perm~s required for building in <br />a flood hazard area. <br /> <br />3. Using the expertise of local engineers, determine the <br />depth and veloc~y of the 100-year fiood flow which <br />would affect the site, including the possible effects of any <br />debris hazards. <br /> <br />4. ELEVATETHE <br />STRUCTURE <br />sO that the low- <br />estfloor(includ- <br />ing basement) <br />is at (orprefera- <br />bly above) the <br />determined <br />flood depth. <br />The most effec- <br />tive methods of <br />elevating struc- <br />tures on fans are <br />to use piles or <br />columns, or to <br />elevate on ar. <br />mored fill. <br /> <br /> <br />5. Flood walls can <br />also be used to <br />divert flow <br />around elevated <br />structures <br />where expected flood flows are of minimal depth and <br />veloc~y, where there is no potential for debris hazards or <br />increased damage to adjacent structures. <br /> <br />Figu,. J 7. <br />Th/. ham. Is undHconstlUt:tlon on IIn .er/v. <br />alluvial 'an billow the IIcDoliW1J Mount.ln.ln <br />Scottsdale, Arlzofllt. <br /> <br />6. Avoid the placement of windows and doors on the uphill <br />side of the structure to keep debris and flood water from <br />entering the buildi,'g. If such openings must be used, <br />they shouid be reinforced to strengthen resistance against <br />debris and hydrodynamic forces. <br /> <br />- <br />