Laserfiche WebLink
<br />Mr. Gene Jencsok <br />September 25, 1979 <br />Page Two <br /> <br />Since the water surface profiles of the two studies are different throughout <br />most of the study reach, a comparison of these profiles does not seem warranted. <br />The effort involved in putting together this profile comparison is considerable, <br />and its value seems limited. If, in fact, the comparison is necessary, please <br />contact me and it will be provided. <br /> <br />In regard to your letter of September 5, 1979, your first question of cornrnun~ty <br />base maps is one of FEMA policy. For these communities, no reproducibles of <br />topographic mapping used as work maps were obtained or required as part of <br />our contract. These ori':jinal work maps were submitted to FEMA, and only a <br />pencil copy was retained in our files. If you require these work maps, please <br />contact our office and Lois single copy will be loaned for a period of time. <br /> <br />Finally, the "I-foot ris,"" floodway criterion used in our study was employed <br />with caution bedUitse of ':he high velocity flow in these mountain streams. Our <br />floodplain analyses show<ld that, in general, these streams have a deep, well <br />d<lfined channel section 1:hat carries a high percentage of the lOO-year flows <br />at high velocities and g<lntly sloping overbank areas which convey shallow channel <br />overflows at low velocities. Our floodways encroached only into these overflow <br />areas. As a result, most of the surcharges in water surface elev.a.tions are well <br />below 1 foot. This method of computing a "I-foot rise" floodway identifies an <br />appropriate high hazard channel in these mountain streams. <br /> <br />If you have further questions regarding these <br />contact me, and "e can discuss them further. <br />is appropriate, we will be happy to attend. <br /> <br />Flood Insurance Studies, please <br />If a meeting together with FEMA <br /> <br />Sincerely, <br /> <br />GINGERY ASSOCIATES, INC. <br /> <br />1rm <br /> <br />e C.' ~t'-.. i.. C'VI) <br />PFM: ss <br /> <br />Patrick F. Mulhern, P.E. <br />