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I I I I I I I I I I I I I I I I I I I The locations of the reaches that were determined as the flooding sources for the Town of Silverthorne are shown in the Flood Profiles (Exhibit 1) and summarized in Table 3. 5.2 Flood Hazard Factors The Flood Hazard Factor (FHF) is the Federal Insurance Administration device used to correlate flood infOlmation with insurance rate tables. Correlation between property damage from floods and their FHF are used to set actuarial insurance premium rate tables based on FHFs from 005 to 200. The FHF for a reaeh is the average-weighted difference between the 10- and 100-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 100-year floods is 0.7 foot, the FHF is 005; if the difference is 1.4 feet, the FHF is 015; if the differenc1e is 5.0 feet, the FHF is 050. When the difference between the w- and 100-year water-surface elevations is greater than 10.0 feet, accuracy for the FHF is to the nearest foot. 5.3 Flood Insurance Zones After the determination of reaches and their respective Flood Hazard Factors, the entire incorporated are:a of the Town of Silverthorne, Summit County, Colorado was divided into zones, ea<;h having a specific flood potential or hazard. Each zone was assigned one of the following flood-insurance designations: Zone AE: This is the flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the FrS by detailed methods. In most instances, BFEs derived from the detailed hydraulic analyses are shown at selected intervals within the zone. Zone AH: This is the flood insurance rate zone that corresponds to the areas of 100- year shallow flooding with a constant water-surface elevation (usually areas of pond in g) where average depths are between 1 and 3 feet. The BFEs derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Zone X: This is the flood insurance rate zone that corresponds to areas outside the 100-year floodplain. This zone delineates areas of 100-year sheet flow flooding where average depths are less than 1 foot, areas of 100-year stream flooding where the contributing drainage area is less than 1 square mile, or areas protected from the 100-year flood by levees. No BFEs are shown within this zone. 5.4 Flood Insurance Rate Map Description The Flood Insurance Rate Map for the Town of Silverthorne is, for insurance purposes, the principal result of the Flood Insurance Study. This map (published separately) contains the official delineation of flood insurance zones and base flood elevation lines. Base tlood elevation lines show the locations of the expected whole-foot water-surface elevations of the base (100-year) flood. This map is developed in accordance with the latest guidelines published by the Federal Emergency Management Agency.