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P,\ST FLOO:JS l I , periods of late sprioq and ear1y faU when polar air intru~ior.s are !nOst intenaive. ~vailable records irAicate that Qno~.el~ has seldom con- ~ributed to flood occurrcnces except whcn augmente~ with neavy rainfall. The physical features of the ...at.ershed ar" all cor.<lucive to a rilpid concentration of runMoff resulting i~ flash floods Charact"rized by high peak flows, moderate volumes and short durations. Sources of Data and Records Significant atream stag~ and di~charge recor~s indicating floed pOtential are not available for Fountain Creek. A stream I I gaging station estilblished in April 1958 now operiltes 0.5 ~iles east of a bridge on u.s. Highway 24 near the west city limits of Colorado Springs. Flow records from thb station are ir.ad"quate tOd"fine hydrOlogic conditions for the study reaches considered in this report. Historical documents, newspaper files, publications of the u.s. Geological Survey and the Colorado Water Reoords were sources of information regarding past floods. The flood profiles and flooded area maps were developed from this material, along with the results of studies, field investigations and office computations. The majority of the flood producing storms over the Fountain creek watershed occur from May through August. It is dur- ing this season that the temperature contrast between surface air and the upper air is the greatest. This ~axinun contrast in temper_ aturecausestheheaviestprecipitatior.. Duringthispcriod,masses of warm, moist air, generally from the Gulf of Me~ico, and oold \ I I , I I Summary of Historical Floods Historical sources disclose that several flccds, of various ~gnitudes, have inundated and inflicted da~ge in so~e portion of tr.e study area since l664. Historical records of floods arcpri,.,arily informative on flooding effects arA specific information on the intensity, duration, and magnitude Of the storms and flooes is generally lacking. Direct flood losses in the Manitou Springs and west Colorado Springs area have consisted principally Ofdarnage to cellars, lawns , grounds of urban, pUblic, and resieential properties, and to munici. ~lly owned property such as ~treets, storm 5ewers, wat~r snd gas lines. Indirect losses incluc'e such ite"'~ as ~.u"",n suffering b~c"use Ofinjelrya"de"?,,sur,,; int"-rr,,ptionsoftraffix;:aCldbusincss;and the effect of adverse puhl icit'j on t~.e tourist trade. Flood Season and Characteristics co~paratively dry ~ir from the pol~r regions combi~e over rr~untuin ~lood Descriptions Followi.ng are de~criptions of known laroe flood" that have occurred iT' ~anit.ou Springs and """,,t color"do Sprinq$. inclllding excerpt~ from locally p~blished news acco~nt~. -regions causing incr(!a~,"d frontal storms ;\nd s1.Umlcr thu"derstorm activity. The latter, most active during July ~nd August, is often ~istinguished by more intense rainfall at random locations. This intens~ rainfall, known as "cloudbursts" occurs only wh~re thN'C is a marked rang~ in temperatur" within a relativ~ly ~mall 3rea ~nd usuaUy lasting a v"ry short time. 1'hiscondLtionexistsnearclln- yon heads where warm, moisture-laden air drifts upward through the canyons to higher altitudes where the reduction in te"'p~ratur~ caus"s rapid condensation resulting in torrential rainfall ~nd damaging floods. The severest storms otten occur in the transitional July 8, 1882 1'he fOllowing"roexce,.pts from the Colorado Sprinqg 'I,'~ckl:! G"~et~e: . . . en" of the mo~t destructiv~ cloudbursts or w"ter~ spOuts th3t has ever taken place in this locality, if not in the ~ute, occurred at ~'''nitou y"s~"rd"y after"o(ln at>ou~ , ,