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Mr. Ron Bottoms, City Manager <br />October 1, 2008 <br />Page 14 of 31 <br />k I o t z associates <br />reports on severe flooding damage than to incidents of repetitive structure which <br />are, in turn, given more weight than flooding reports (whether for residences or <br />streets) arising from tropical storms, a modification of the flooding intensity map <br />can be created by giving different levels of importance to different types of <br />flooding reports, as given in the following table: <br />Policy Weight Factors for Flood Problem Intensity <br />Type of Flooding Report Policy -based <br />Weighting Factor <br />Report ,Tye _l -, Reports on severely damage residences 5 <br />Report Type 2: Repetitive loss reports on structural 4 <br />(residential) flooding <br />Report Type 3: Tropical Storm Allison flooding in 1 <br />2001 <br />Report T.Y.De 4: Tropical Storm Erin flooding jn_2006 I <br />'_Report Type 5: Miscellaneous but reliable data 1 <br />The choice of different weights is a policy -based decision. Our primary concern <br />is structural flooding, but street flooding may also be indicative of potential <br />structural flooding. Thus for evaluation of long term flooding problems, the <br />weightings listed in the table above are considered reasonable <br />When the above weightings (for the first 4 types only; no data are available for <br />Type 5) are applied to each flooding incident report and the flood intensity map is <br />rescaled to have the same average intensity as the un-scaled map (in order to <br />provide comparison between policy -scaled and un-scaled intensities), the intensity <br />maps of Exhibits 7, 8 and 9 results. Table 1 shows problem intensity assuming <br />that each type of flooding occurrence has the same importance and assuming that <br />the policy -weightings given in above table are applied. <br />The floodinR problem intensity maps of Exhibits 4, 5 and 6 or 7, 8 and 9 can be <br />used to identify and rank areas for which remedy of problems should be <br />developed as part of the long terms solution to flood problems in the City. Ihe <br />areas with hip -hest flooding problem intensitv are in most urRent need of remedy, <br />Comparison of the Exhibits 4 and 7, 5 and 8, and 6 and 9 shows considerable <br />similarity between the two intensity results, though the use of the policy <br />This comparison between the hot spot identification of Exhibits 4 and 7, 5 and 8, <br />