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Potential Floods The I ntermed iata Regional Flood has a probability of occurrence ofonce!n 100 years. Such a potential flood Is Increasingly being accepted by the public as a minimum limit for application of local regulations for flood plain use. Any large flood !n tho Cherry Creek study reach would result only from runOff downstream from the Cherry Creek Dam. The Standard Project Flood Is defined as the largest flood that can be expected from the most severe combination of meteorological and hydrological conditions that are considered reasonably Charact?r- Istlc of the. geographical region Involved. Stili larger floods are possible but the combination of factors necessary to produce such floods bocome even more improbable as their magnitude Increases, Discharge probability relationshipS were developed for the streams studied In this report and are reproduced on plates 2 through 7. DISCharges for potential large floods on lower Cherry Creek, S<lndCreek, and Toll Gate Creek are shown In table I. KazardsofLargeFloods The areas flooded by the Intermediate Regional and Standard Project Floods are shown In plates 2 through 7, Also shown on these plates are profiles that Illustrate the depth of f!oodlng by these potential tloods through the various study reached. IndIcations of adequate channel capacity at certain locations does not mean that adjacent flood plains will not be flooded. Itisposslblethat overland flows may originate from some upstream location where chan- nel capacity Is exceeded. Also, obstructions at bridges may cause pondlng and higher flood stages. The flooded area maps reflect these considerations. Table I POTENTIAL FLOOD DISCHARGES (inc.f.s,l ExIsting and PotentIal Development The downstream portion of the Cherry Creek basin Is character- Izedbytheconcentr<ltedurbandevelopmentofDenver-lndtJstrial, commercial, and middle-to-high-priced residential. The downstream portion of the Sand Creek basin is experiencing rapid commerc!al and industrial development. ReSidential development IS located in the mldd Ie portion of th\> b<lsi n at the S~nd-Toll Gat(' Creek conf luence. Projoctions of population, employment, and Income data for the study areas indicatc3nced for additional dwelling units, c,""",cr cial establishments, and manufacturing olants, ThIs need creates pres- s"restocro..J ;r;onr:OO::p:aln Idnds. a"tfhisshQ\>ldooilVold..J. I nt<lrmodiato St<ln~ard RegIonal Project Location floOO Flood Cherry Creek: at Goldsmith Gulch 9,100 20,200 atrnouth 10,900 21,200 Sand Creek: at Buckley FIeld 33,000 60,500 at Toll Gate Creek 38,500 81,700 at mouth 49,500 91,200 Toll Gate Creek: at Buckley Field 20,000 32,700 at mouth 21,900 31.100 Witness the destruction by prior floods. FrO'1l Cherry Creek 0"", to the Denver County line-MissIssippI Avenue - about 250 acres is subject to Inundation by large floods. About 40 percent of this area is developed - about oQually betw~on resldontlalandcClMlOrcllll.ltlsantlcipatedthatthefloodplafn will t>e fully developed by 1990. From the county line to the Platte River there are about 500 acres in the Cherry CrOOk flood plain, It Isalmostfullydovelopedwlthresldentlallmprovomentsatthe upstream end and commercial and Industrial toward the downstream end. " "