1200 INDUSTRY ST 2018-01-01 MF Import

LO PROJECT OVERVIE�V I This project is a po�lion of the Seaway Busi�icss Centcr situatcd on the southcast corner o��1en'ill Creek Parkway and liardeson Road within ihc City of I:vcrctl, Washington. As such this project wil) cotnply widithe ovcrall Maste: Drainage Plan, the Pinal Stonn Drainage Rcport for the Proposed Senway Center dated October 10, 20U2, and ihe revised stonn driinage calculations dalcd OctoUer 21, 2002, all previously submilted and approved by lhe City of Gverctt. "Ihis portion of the entire Seawuy Business Park will include construction of Building� and I3uilding ['. Thc sitc work for Buildin�E will consist of an approximately 99,150 syuarc foot warchouse Uuilding and Building F will consist of an approximatcly 47,U50 squarc foot warchousc building. Site work for cach bailding will also cunsist of on gradc luading docks, drivc aislcs, parking, storni drainagc colleclion systcm and utilitics. As stated in thc Pinal llrainagc Rcport, thc roof runoff Gan 13uilding B and I3uilding � will bc divcrtcd to lhe existing, combincd infiltratiai/detention pond to thc north of Building 1�. Thc combincd infiltratio«/detcntion pond was constructcd undcr thc [3uilding G pcnnit, and was sizcd to accommoJatc thc roofrunoff from Building E and I3uilding F. Thc combined intiltratio��/detc��tion fticility was sized in proportion to thc roof area to be servcd. In accordancc with thc Ovcrall Mastcr Drainagc Plan for thc cntirc Sca��ay I3usiness Park, approximately I 1.43 a�res will be divertcd to an intiltrationidelention � system to be dischargcd to the Glemvood Creck Lrainage 13asin. Pcr the Pinal Drainage Reporl and thc revised drainage c�lculntions, the required detention storage volume for tLe 1 L43 acres is approximatcly G9,900 cubic fecL The siring calculatiuns for the intillration/dctcntion ft�cility assumcd roof areas of 94,=�00 squarc fcct and 42,650 squarc fect 1or Building C and 13uilding I' respcctivcly, which i� Icss than thc aclual ara�s, but also applied a safety factor of 1.41. When taking into account the actual roof arcas of Building G and [3uilding �, thc safcty factor Uccomcs L35 (scc attached siring calculations.) ln addition, thc roof runoff Irom existing Building G will bc divcrtcd around Quilding r and into thc infiltration/dctention pond. Thc runoff gcnerated ��rom the remaindcr of th�site (i.e., parking, landscaping) will Uc collected and conveycd to the existing stonn drainage com�cyanec system which dischargcs to thc cxisting combincd dctcntion and watcr quality pond localcd at dic northwest comer of Seaway F3usiness Centec A poriion of the site drain�gc from cxisting Building G will bc divertcd around Building P inro dic cxisting stonn drainagc cum�cyancc systcm. Plcasc scc thc attached convcyancc calculations for thc sitc cum�cvnncc as wcll as thc roof com-cyancc. �I