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The difference between the contour maps and the LSWMP is that the LSWMP assumes <br /> ultimate conditions and infrastructure to accommodate stormwater flows associated <br /> with ultimate conditions. In this case,the existing �12" CMP culvert under Old <br /> Chrystal Bay Road is proposed to be increase to a 24" RCP. Increased flow from <br /> upstream is then proposed to be attenuated using the proposed 18" pipe at the <br /> Moore property and corresponding upstream storage. Therefore, it is recommended <br /> that the 18" pipe shown in the SWMP be installed at the Moore property at this time, <br /> as shown in the City's LSWMP. <br /> 3. The observations from October reflect the current watershed's response to multiple <br /> small storm events. The largest daily rainfall amount in the area in October was <br /> approximately 2.5". This storm depth is approximately equivalent to a 1-yr storm <br /> event. The LSWMP storm drainage system is designed to convey flows generated <br /> during a 100-yr storm and ultimate conditions. For these reasons, and the reasons <br /> stated in#2 above, we recommend installation of the 18" pipe shown in the City's <br /> LSWMP. <br /> 4. It is accurate that flow from the existing 24" culvert crossing does not contribute flow <br /> to the Moore property. This was correctly reflected in the stormwater model and the <br /> proposed design for the 18" pipe and berm. <br /> 5. As discussed with Steve Moore, we recommend that the existing 5" clay tile line be <br /> discharged to a structure that drains to the proposed 18" pipe as a precautionary <br /> measure. <br /> Please don't hesitate to call me directly at(651)604-4755 if you have any questions! <br /> Page1 of1 <br />