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,~ which displayed water-surface profiles and designated areas flooded by the intermediate-regional and standard-project floods. An intermediate- regional flood has a frequency of occurrence of once in lOa years. The standard-project flood, (the flood that may be expected from the most severe combination or meteorological and hydrological conditions con- sidered reasonably characteristic of the geographical area in which the drainage basin is located, excluding extremely rare combinations,) used in the Flood Plain Informatio:~ report was of less magnitude than the 500- year flood and was, therefore, not directly comparable. One hundred-year floodflows in both reports were found to be identical, but areas and flood profiles on the Colorado River in the present Flood Insurance Study varied from those in the Flood Plain Information report due to construc- tion on Interstate Highway 70 in the Colorado River flood plain since the Flood Plain Information report was prepared. Hubbard Gulch was studied by approximate methods for the present Flood Insurance Study and the stre~n reach studied differed from that in the Flood Plain Information repor1: (Reference 8) except for a short se~ent just upstream from the corporate limits of Rifle. Both reports show the lOa-year flood areas that are compatible for this se~ent. Other data on Hubbard Gulch are not comparable. A Flood Insurance Study of Rifle (Reference 9) was prepared by the u.s. Army Corps of Engineers, Sacramento District, in 1972. The study included the Colorado River and Hubbard Gulch. Both studies covered 10-, 100-, auu SOO-year floods. Basic data for the ,Rifle Flood Insurance Study were found to be compatible with the present Flood Insurance Study; but, for the Colorado River, areas designated as being flooded by the lOO- and 500-year floods and Flood Profiles differed. The differences were due to construction of Interstate Highway 70 in the flood plain since the earlier Flood Insurance Study was prepared. The present Flood Insurance St:udy for Garfield County is authoritative for purposes of the Flood Insurance Program, and data presented herein supersede or are compatible with all previous determinations. 7.0 LOCATION OF DATA Survey, hydrologic, hydraulic, and oOther pertinent data used in this study are available at the Federal Insurance Administration, 45l 7th Street SW, Washington, D.C. 204l0. .~ 8.0 BIBLIOGRAPHY AND REFERENCES 1. Pacific Southwest Inter-A.gency Group, et. a1., Appendix IX, Flood Control, Upper Colorado I<.egion Comprehensive Framework Study, 1971 22