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CHAPTF.:R II INTERPRETATIOlI AND USE OF REPORI DAIA These locations are as follows, 1. Table-4,"FloodFrequency,ElevationsandDischargeDats." A. Flood Prequenoy and Dischaqr;e 2. flooded lire a Plates 1 through 4 (flood contoClrs shown as wiggly li nes) This report was prepared to be compatibie with the H.B. 1041 designation, Federal Emergency Management Agency (FEMA) flood insurance rate studies, and oan be adopted by local governments for regulation purposes. The 10-, 25-, 50-, 100-, and 500-year frequency flood events were used in the ana lysis. These flood events have a probability of oocurring once in the number of years indioated. For exa=plc, the lOO-year flood has a one percent chance of being equalled or exceeded in anyone given year. J. Flood Profiles on Plates 5 through 9 (watN sudace profiles were plotted from the data presented in Table-4) 4. Typical Cross Sections on Plates 10 throClgh 11. The moat important use of the 100-year flood data is for the description of the floodplain and its land Use regulation. The COlorado State statutes consider the lOO-year flood as the flood event to be used in designing and , protecting;all buildings and structures to be used for human occupancy. This level of flood protection has reoeived nationwide acceptance. The flood profiles may be used in areaS '~ere ~ontroversy arises over the 100-year flood boundary shown On the flooded area plates. Since the flood profiles give the elevation at a specific point on the reference line, the high water elevations can be conveyed to the ground. A numher of control markers are in place along the study resch which can be used for this purpose. The markers consist of 3-inch diameter brass caps set in concrete or a cap and rebarwhich are stamped with appropriate identification. The pertinent information and location a of the control markers are listed in the following table. Information concerning more frequent flood events is provided to allow assessment of the riaks of flood damages during lesser floodS. Minor roads, recreation facilities, and livestock structures may often be designed based on floods smaller than the 100-year flood. A higher risk of damagc may be acceptable for the desi~ o.f the." types of facilities. TABLE-l CONTROL MIl.RKER DATA Field Identification Elevation Location B. Flood Elevations SCS-BM-l 49510.69 Cap' Rebar, I' south of fence COrner post, 4'N. of Cone. irr. ditch; 9S' S.!. of intersection of Hwy 52 and county line road; 7' S.E. of power pole. CONTINUED Water surface elevations for the 10-, 25-, 50-, 100-, and SOO-year flood for Coal Creek can be found in four locations within this report. -6- - , -