Laserfiche WebLink
1 <br /> ' Detention Design <br /> Stormwater detention for the site will be provided in the Associated Boulevard Detention Pond. <br /> Runoff from Lot `L,' assuming developed conditions,was included in the original calculations <br /> for the design of the existing detention pond. See the hydraulics report titled Stormwater Site <br /> IPlan, Associated Boulevard, June 2001, for more information. <br /> Water Quality Design <br /> A StormfilterTM cartridge filter vault will provide water quality treatment for the paved areas <br /> around the Valley Electric building. Stormwater will pass through a pretreatment vault to settle <br /> out larger sediments and trash before entering the StormfilterTM. The filters use a CSF Leaf <br /> media for sediment, oil, soluble metals, and total nutrient removal. The filter is sized to treat the <br /> six-month storm using the StormfilterTM Design Manual and City of Everett requirements. See <br /> Appendix B for StormfilterTM sizing calculations. A 16 x 8 foot vault with 16 filter cartridges is <br /> required. The six-month storm flow rate was calculated using the Santa Barbara Urban <br /> Hydrograph method and the StormshedTM computer program. Runoff greater than the six-month <br /> storm will bypass the StormfilterTM and discharge directly to the detention pond. Runoff from <br /> the building roof bypasses the filter vault. <br /> ' The StormfilterTM should be maintained according to City of Everett requirements and the <br /> manufacturer's maintenance manual. The maintenance manual is included as Appendix C. <br /> Off-site Runoff Design <br /> Runoff from the adjacent property to the south currently ponds on Lot 'L.' A sedimentation pond <br /> will be constructed south of the site, and diversion swales will direct off-site water from <br /> undeveloped property to the south to the pond and prevent this off-site water from entering the <br /> I site. The sedimentation pond was sized for the 10-year storm per City of Everett Stormwater <br /> Management Manual Section 2-5.7. The outfall from the sedimentation pond will run along the <br /> east property line and combine with flows from the Valley Electric site downstream of the <br /> ' proposed StormfilterTM. The combined outfall will discharge to the Associated Boulevard <br /> Detention Pond. See Appendix B for sediment pond calculations. <br /> sjs\27p1\03\003_valley electric\hydraulics\hydrpt.doc\jj <br /> Valley Electric Building August 4,2003 <br /> ' Hydraulics Report -3- Revised August 20,2003 <br /> Reid iddleton <br />