FLOOD06864 - Laserfiche WebLink

Home Browse Search

During the determination of the study areas for Canon City, it was decided that Northeast Canon Drainage East Branch, Northeast Canon Drainage West Branch, Southeast Canon Drainage, Forked Gulch. West Forked Gulch, and Sand Creek, should be studied in limited dl'tail, Therefore, no fl oodways have been computed for these streams, 5,0 INSURANCE APPLICATION In order to establish actuarial insurance rates, FEMA has developed a pro- cess to transform the data from the engineering study into flood insurance criteria, This process includes the determination of reaches, Flood Hazard Factors (FHF), and flood insurance zone designations for each flooding source studied in detail affecting the City of Canon City. 5,1 Reach Determinations Reaches are defined as lengths of watercourses having relativply the same fl ood ha zard, ba sed on the average wei ghted difference in wa ter- surface elevations between the 10- and IOO-year floods, This differ- ence does not have a variation greater than that indicated in the following table for more than 20 percent of the reach: Average Difference Between 10- and IOO-Year Floods Variation Less than 2 feet 2 to 7 fee t 0.5 foot 1. 0 foot One reach meeting the above criteria was required for the flooding sources of the City of Canon City along the Arkansas River, one along Sand Creek, one along Forked Gulch, one along West Forked Gulch, two along Southeast Canon Drainage, one along Northeast Canon Drainage East Branch and one along Northeast Canon Drainage West Branch, The locations of the reaches are shown on the Flood Profiles, 5,2 Flood Hazard Factors The Flood Hazard Factor is used to correlate flood information with insurance ra te tables. Cor reI a ti ons between property damage from floods and their assigned FHFs are used to set actuarial insurancp premium rate tables based on FHFs from 005 to 200. The FHF for a reach is the average weighted difference between the 10- and IOO-year flood water-surface elevations expressed to the nearest one-half foot, and shown as a three-digit code, For example, if the difference between water-surface elevations of the 10- and IOO-year floods is 0.7 foot, the FHF is n05; if the difference is 1.4 feet, the FHF is 015; if the difference is 5.0 feet, the FHF is 050. When the difference between the 10- and IOO-year water-surface eleva- tions is greater than 10.0 feet, accuracy for the FHF is to the nearest foot. 13