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<br />. <br /> <br />., <br /> <br />Page 2 <br /> <br />2. Discussed the unreasonably high flood discharges in some <br />small drainage basins--according to FIA Flood Insurance Study <br />policy, if the study area is less than one square mile, the <br />flood elevations are not necessarily to be mapped in that area. <br />However, the detail hydrology still is needed, if the flood <br />discharges from upstream subbasin, which is less than one square <br />mile, will affect the discharge values determined for downstream <br />areas. There were unreasonably high discharges in several small <br />drainage basins presented in "Report on Hydrologic Investigations, <br />Flood Insurance Study, Colorado Springs and E1 Paso County, <br />Colorado," by U,S. Army Corps of Engineers, Albuquerque, New Mexico <br />in December, 1976. The flood discharges from those small sub- <br />basins do affect the flood discharge values determined for down- <br />stream areas, Mr. Frank Jaramillo, Chief Hydrologist from USACE, <br />Albuquerque Office, has agreed to reduce those unreasonable dis- <br />charges. Mr. Jarami110said that he is going to use the 100-year <br />peak discharge--2,600 cfs per square mile as a upper limit for <br />those small drainage areas. <br /> <br />3. Discussed the hydrology in Sand Creek--Sand Creek in E1 Paso <br />County, Colorado, Soil Conservation Service, (SCS) in 1973 did the <br />flood hazard analysis and Colorado Water Conservation Board had <br />designated in 1974, based on SCS Flood Hazard Analysis Report. <br />USACE, Albuquerque Office presently is doing flood insurance study <br />for FlA. The 100-year peak discharges determined by USACE are <br />50-100% higher than SCS 100-year peak discharges and the 500-year <br />peak discharges determined by USACE are 100-170% higher than SCS <br />500-year peak flows, The major reason for the discrepancies in <br />peak discharges is because the methodology used by both agencies is <br />different, USACE will meet with SCS to solve the hydrology problems. <br />FIA and CWCB would like to sit in on that meeting. USACE will hold <br />the hydraulics runs until the hydrology problems are solved. <br /> <br />4. Discussed the hydrology in Jimmy Camp Creek--Jimmy Camp Creek <br />in E1 Paso County, Colorado, USACE, Albuquerque Office did flood <br />plain information study in 1973 from river mouth at Fountain Creek <br />to River Mile (RM) 4.33 above Fountain Creek, SCS Denver Office <br />did flood hazard analysis in 1975 from RM 4.33 above Fountain Creek <br />to the basin headwaters, CWCB had designated in 1976, based on SCS <br />study. One hundred-year flood peaks are consistent from both agencies, <br />However, the SOD-year flood peaks are different, USACE's value is <br />approximately 60% higher than SCS' value. USACE will contact SCS and <br />solve this problem. <br /> <br />5. Discussed the hydrology in Cottonwood Creek-Cottonwood Creek <br />in E1 Paso County, Co10rado--USACE, Albuquerque Office did flood <br />plain information study in 1976, and CWeB ha~ designated the ~tudy <br />