Laserfiche WebLink
<br />. <br /> <br />the feasibility of increasing the size of the Upper Lowry outlet <br /> <br /> <br />works to reduce embankment and land costs. The increased costs <br /> <br /> <br />for the outlet works would, in both cases, exceed the potential <br /> <br /> <br />savings in embankment and land costs. <br /> <br />The above plan for lOO-year storage at Upper Lowry Dam pro- <br /> <br /> <br />vides enough supplemental storage to make it possible for Kelly <br /> <br />Road Dam to store a flood slightly greater than the lOO-year <br /> <br /> <br />event but considerably less than the standard project flood. <br /> <br /> <br />Protection from the standard project flood is considered to be an <br /> <br /> <br />appropriate level of protection in an urban area. With the plan <br /> <br /> <br />for lOO-year storage, the standard project flood peak discharge <br /> <br /> <br />downstream from Kelly Road Dam would be reduced from lO,380 to <br /> <br /> <br />5,340 cubic feet per second. Although this provides for a sub- <br /> <br /> <br />stantial reduction in downstream flood damages, there would still <br /> <br /> <br />be a considerable hazard associated with floods that exceed the <br /> <br /> <br />laO-year event. A plan which would fully utilize the feasible <br /> <br /> <br />site capacity and provide standard project flood storage at the <br /> <br /> <br />Upper Lowry Dam was, therefore, evaluated. <br /> <br />Storage for the standard project flood at the Upper Lowry Dam <br /> <br /> <br />would also make it possible to store the standard project flood <br /> <br /> <br />at Kelly Road Dam without overtopping the l20-foot-wide spillway. <br /> <br /> <br />The peak discharge for the standard project flood would be reduced <br /> <br /> <br />from lO,380 cubic feet per second to 570 cubic feet per second <br /> <br /> <br />through the outlet works. It should be recognized, however, that <br /> <br /> <br />this would not completely eliminate the possibility of downstream <br /> <br /> <br />damages; flooding would still occur due to the accumulation of <br /> <br /> <br />runoff from the uncontrolled area downstream from Kelly Road Dam <br /> <br /> <br />and from upstream floods of greater magnitude than the standard <br /> <br /> <br />project flood. An emergency flood warning and evacuation plan <br /> <br /> <br />would still be required. <br /> <br />. <br /> <br />l-5 <br />