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100 years on i'he average. A Stand"rd ProJeci' Flood would occur much less frequently than an Intermedl"te Reglon"l Flood. Although a Si'andard Projeci'Floodlsarareeveni', It can be expected to occur in the future. Floods I"rger than a Standard Project Flood "re possible; however, tho combination of eveni's necessary to produce such I"rge flows would be ext.-emelyunllkely. and Standard Projeci' FloodS (Plates 5-151. These plates show that most flooding from i'hese streams would be confined by high ground to relatively narrow strips along the streamways. However, the meadow area extending from the upper limit of the study are" downsi'ream to Hem"nn Road along i'MRoarlng Fork River would beco"'Plei'ely Tnund"ted. Flooding "long the remainder of thesi'udy reach of the Roaring ForkRTver is relative Iywell ccnflned to the channel by high banks except for the are" just below He- mann Road and the area near Hall"m Lake. FloodlngfromCastleCreek closely parallels the stream course throughout the study reach. Flood- ingfromHunterCreekgeneraIIYPi!lrallels1"hestreamas"wldebMd except in areas constricted by canyons or obstruci'lve bridges. The area thllt would be tlooded by an Intermediate Regional Flood comprises about 300 acres as summarized below: HAZARDS OF lARGE FLOODS The amount and extent of d"mage caused by "ny tlood depends on the topography ot the "rea flOOded, depth and duration of floodIng, velocity of flow, rate of rise, lInd developments In the flood plein. An occurrence of all Intermediate Regional or St"ndard Project Flood on streams in the study area at the present time would result In Inundation of rural meadowereas; demagetoresldences, roads,stree1"s, bridges, i!lndpubll c utilities; and Interrupi'lon of traffic. Floodwater flowing at high velocity and carrying tleetlng debris would create ccnditlons hezardous to persons and vehicles attempting to cross flooded erees. In generel, floodwater 3 Or mone feet deep and tlowing at a velocity of 3 or more feet per second could easily sweep a person otf his feei', thus creating a definite danger of Injury or drowning. High velocity flows through Aspen could erode streambank~ thereby threatening the foundations of buildings and bridge abutments and creating hazards i'o curious spectators. Cold nights during the early part ot the runotf season cause streets, subject to shallow tloodlng1"o beoome glazed wIth Ice. Sewage, garbage, and other organic materials ca~~led or deposited by tloodwate~ create ha.ards to health. Serious prOblems could develop In providing omergoncy medic~l, fire, and I~w enforcement services to areas Isolated by floods, Areas In 100 year tlood plain Stream Total Undeveloped Built-up RoarIng Fo~k River 282 '" 28 Castle C~eek " 11 2 HUnTer Creek 9 8 , Total 30. m " Flood losses in the Aspen area would Include damage to grazing lands through erosion and deposli'lon of debris; damage to farm and ranch Improvemeni's, such as Irrigation systems and fences; damage to multl- family residential developments; damage to corM\erclal bulldings;darnage to pa~ks and other recreational facl If ties; and sovere dpm(lge to roads, brIdges, and public utilities. Strellmch""'nelswouldbesubjectto severe erosIon. FLOODED AREAS AND FLOOD DAMAGES Due to the wider tlood plain, greater depth ot flooding, and highe~ velocity of flow during a Standard Project Flood, damage would be more extensive than during an Intermediate RegTonal Flood. Plates 16-17showwatersurfaceprofllesofthelntennedfateReglonal and Standard Project Floods. Depth of flow In the ChMnels can be astimated The approximate limIts ot Inundation along the RoarIng Fo~k River and Castle and Hunter C~eeks that could result from a Standard Project Flood are shown On Plate 4, whiCh Is also an Index to more detailed maps showIng the aroas that could be Inundated by the Intermediate Roglonal " 20