Map 1. Existing 100-year Floodplain and Most Flood-Prone Areas in the FWOP from Prior Analyses.
Source: URS Corp.
As part of the analysis for the new dams, URS engineers modeled future flooding conditions in the FWOP for 1, 2, 5, 10, 25, 50, 100, and 500-year events with the dams constructed. For this study, we’re most interested in the post-dam construction flood levels, assuming the dams will get built. This new analysis modifies the 100-year floodplain shown in Map 1, and identifies all properties that will still flood during each of the storm events (1 through 500 years). The greatest concern is for the storms that occur fairly quickly and often, and cause recurring flooding and damage to many properties in the FWOP. These storms tend to be the 10- to 50-year events. For the purpose of this study, we have chosen the 25-year flood level as
Technical Memorandum #1UDT: Characteristics of Flood-Prone Parcels