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<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />The flow velocities in the channels of the studied streams generally <br />range between 5 and 8 feet per second (fps) with maximum channel <br />velocities exceeding 12 to 14 fps along some reaches of Todd Creek and <br />its tributaries. High velocity flows are also characteristic of <br />reservoi r embankment overtoppi ngs in all of the studi ed streams. <br />Velocities in the overbank typically range between 0 and 6 fps. <br /> <br />Velocities in excess of 8 fps can cause severe erosion of stream <br />banks, and are capable of transporting large rocks and debris. <br />Velocities in this range can also erode roadway embankments or fill <br />around bridge abutments, causing possible bridge failure. Lower <br />velocities of approximately two fps or less will deposit debris and <br />silt. <br /> <br />- SlMfARY - <br /> <br />This report has identified the probable flooding limits resulting from <br />a 100-year runoff event in the Todd Creek drainage basin. <br /> <br />The floodplain limits are based on hydrologic information developed <br />for future basin conditions and existing floodplain and channel <br />conditions as shown on the maps. Floods of greater magnitude can and <br />will occur in which the limits of flooding will exceed those shown in <br />thi s report. <br /> <br />Presently there are few areas where flooding may result in extensive <br />flood damages. Regulation of future floodplain construction <br />activities will serve to minimize increases in the flood damage <br />potential. Improvements to the channel or crossing structures will <br />serve to reduce the potential for flood damage. <br /> <br />19 <br /> <br />