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<br /> <br /> <br /> <br />arc <br /> <br /> <br />Table 3. Existin and Pro osed Peak Runoff Rates <br />Storm Event Existing Conditions Proposed Conditions <br />s cfu cfu <br />2 1.57 1.74 <br />5 3.09 1.79 <br />10 4.37 1.83 <br />lOO 8.44 1.98 <br /> <br />As illustrated in Table 3, it appears that the proposed peak discharge rates for all storm events <br />except the 2-yr will be less than existing rates. It should be noted that the high water level <br />obtained from the storage volume modeled was approximately 892 feet. The newly configured <br />pond can be expected to have a high water level somewhere between 892 feet and the existing <br />high water level of 894 feet. Nevertheless, the exact size and configuration of the pond outlet <br />will need to be field verified to better determine proposed discharge rates. The outlet may have <br />to be modified due to the changes in the storage volume. It is possible that the new pond can <br />meet the CRWD's requirement that the existing peak discharge rates for the 2-,5-,10-, and 100- <br />yr storm events. <br /> <br />WATER QUALITY <br /> <br />Water quality for the site was evaluated using P8, a water quality modeling tool model for <br />predicting the generation and transport of stormwater runoff pollutants. The portion of the pond <br />indicated as Dead Storage in Table 2 was incorporated into the model to predict the annual total <br />phosphorus reduction from the site. <br /> <br />The results of the P8 model indicate that approximately 63.5% in annual total phosphorus <br />reduction will be achieved through a pond configured as shown in Table 2. Therefore, this pond <br />is sized appropriately in order to meet the CRWD's requirements for phosphorus reduction for <br />the proposed development <br /> <br />SANITARY AND WATER <br /> <br />The GIS information provided by the City ofRoseville indicates that water main is located along <br />both Elmer Street and McCarrons Boulevard for use for the development. Additionally, sanitary <br />manholes are located within Elmer Street and within McCarrons Boulevard in front of the <br />parcels that are being considered for redevelopment. Therefore, sanitary and water main will be <br />readily available for the development. Both these utilities will need to be avoided when <br />installing a storm sewer across Elmer Street. <br /> <br />CONCLUSION <br /> <br />From our analysis, based on the developable area, drainage, and available utilities, a 40-unit <br />multi-family development would be well suited for the Guptil and Elmer Street parcels. Based <br />on actual wetland and waterbody boundaries and buffers, as well as actual building and parking <br />