6300 MERRILL CREEK PKY BASE FILE 2018-01-01 MF Import

r i� r � Section One nc,�ed to be detained, but it does need to be trcated for water quality. Stormwater water quality treatrnent will be accomplishcd using a wetpond «7th an open water cell and a wetland treatrnent cell. The I wetpond was sized for the volume of the 6-month stortn. 7'}re higher storm flows will pass tivough the wetpond and will be discharged directly into the mgional detention pond. Sce Appendix C for the I Watenvorks calculations for sizing the wetpond volume. Also included in Appendix C are the calculations for sizing the open water cell and the wetland trcatment cell. IStortmvater flow from the building rooftops dces not need to be detained or treated for water quality. This stormwater will be I conveyed in a separate stormwater system from the parking and landscape conveyance system. The conveyance system for the rooftop drainage from the future building will also discharge 1 directly into the regional detention pond. During the first phase of development, the fiiture building pad area will be covered by asphalt treated 63se. Parking will not be allowed on �he iuture ' building pad area and it will have curbing or 3:1 slopes surrounding the area to prohibit vehicle access. When the £uture building is constructed, the temporaary drainage system will be removed and the downspouts will be comected to the conveyance system that t discharges dircctly to the regional detention pond. The stortnwater runoff that «ill be dischargcd into the native , growth protection area will be detained and treatcd for water quality. This will be accomplishe�: by the use of a combination wetpond and detention pond. The �vetpond was sized to treat the � volume of the 6-month storm and includes the use of an open water cell and a wetland treatrnent ccll. The 100-year scortnwater runoff was designed to detain and release at I/2 the pre-developed 2-year Ipeak flow rate. Sce Appendis D for the Watenvorks calculations � for sizing the wetpond volumc. Also included in Apprndix D are the calculations for sizing the open water cell and the wetland � treatrnent cell and the orifice calculations and level pool routing. All of the stortmvater conveyancc systems have been sized by the � use of the rational method for the 25-year, 24 hour stortn. See Appendix E for the basin maps for the three conveyance systems and their respective rational analysis. I I O!her Permlts A National Pollutant Discharge Elimination System(NPDES) Permit is required for this site development. i SofectmnCorporotionLotlFo/'SeawavCenter i•IPrqectll93401011wordlSLR1FDRNdoc � It&NPncfc Novrmbcr7, 1997/poge9 �