Laserfiche WebLink
<br />VERSION 1.0 1/12/95 <br /> <br />B-C PROGRAM: Flood Hazard Risk <br /> <br />User-Entered <br />Flood Estimates <br /> <br />LEVEL TWO <br />Flood Analysis <br /> <br />If desired, user-entered estimates of the annual probabilities of floods of <br />each flood depth can be entered in the BLUE (Override Default) <br />column of the Flood Hazard Table. Making such estimates and other <br />possible modifications of the default flood estimates are discussed <br />below in the LEVEL TWO Flood Analysis section. <br /> <br />There are two ways to conduct a LEVEL TWO Flood Hazard Risk <br />Analysis: <br /> <br />1. The flood data entry table (above) can be filled in with <br />estimates based on limited data or informed judgement. <br />Such an analysis will be less accurate than analyses <br />using full FIS/FIRM (or equivalent) data, but flood <br />estimates will be approximately correct as long as the <br />input estimates are reasonable for the area under <br />evaluation. Such an analysis is a LEVEL TWO analysis <br />because it requires interpolation or extrapolation of <br />limited data andlor other professional judgement about <br />flood risks. <br /> <br />2. The default values of the Expected Annual Number of <br />Floods for each flood depth can be overridden with user- <br />entered estimates. This option requires an independent <br />source of flood data, such as a U.S. Army Corps of <br />Engineers study or other data from a professional <br />hydraulics engineer experienced in flood modeling. Such <br />flood data MUST be expressed as Expected Annual <br />Number of Fioods at the appropriate location and <br />elevation under evaluation. To override the default <br />estimates in the ORANGE column, user-entered values <br />are entered in the BLUE column. Whenever user <br />estimates of the expected annual number of floods are <br />entered, the program uses these values rather than the <br />default values, although the default values are displayed <br />for comparison to the user-entered values. <br /> <br /> <br />7.6 <br />