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<br />FROt:1 :MCLARCHITECS-INC <br /> <br />FAX NO. :651-222-5414 <br /> <br />Sep. 06 2005 03:00PM P5 <br />......._....." ......._M M.~_'.~M___._____.. ..... .M.. Nt <br /> <br />JUL.29'2005 15;26 <br />, , <br /> <br />#2022 P.005/006 <br /> <br />. . Permit Atu'~~on ND;~~:ci-012 <br /> <br />St. Genevieve Cat1,oHe Ch~ <br /> <br />usociated parking area QI'.1 14.(;:t: a,cres. In, addi,ti~ two future <br />additions to the church building fmd ad.ditiorW parking areas are <br />proposed. Reconsttuction of Lamotte Drive and, Heritage Street was <br />r.eviewed under RCWO Pennit 04-035. <br /> <br />2. Runoff from the eXisting building Ill'l.d parkinS tot drai.ns north <br />stormsewer on Heritage Street. The proposed stormwater <br />mmagcmem plan includes a NURP pond and a biotiltratioft basin. <br />Since more than. 50% of the site is proposed for redevelopment, <br />stormwata: managem.ent is required fur all f.mpervious areas <br />(existil1g and Dew). <br /> <br />Dfstdct me CODtl'OI. requirements 4TQ satisfied for both current and <br />fUtw:e phases of the project. District water quality treatment <br />requirem.ent, are satisfied for the current and future impervious e.reas <br />tributary to the proposed NURP pond (both tor the interim pond size <br />and the future pond size). However, a revised grading plan is <br />required demonstratin,g conveya.oce of runoff' ftom t.he CUlTen.tIy <br />proposed impervious areas to the NURP pond, clearly idem.tifying <br />both phases of pond construction (initial phue 'IS. future) and <br />including fb.e future intlltration sweles ool'lsistent with the proposed~ <br />conditions hydrologic calculations. <br /> <br />It is unclear whether the proposed ubipfll.trati('o basi,n~' in, the . <br />northern. portion of the site satisfies t.b.e District.s water quali.1:y <br />treatment requirement for both the existing impervious aroas 8l'Jd. the <br />proposed. en,trance dri.ve. As curren.tly designed, this basin. would <br />functi,on as B detention pond, because l'lO und.erdrttin is proposed to <br />faclUWe fl.lb'ation and insu,fficjent deld. storage (2.S-i.neb event) <br />belQw the outlet is provided. <br /> <br />If this basin is to function. as a NURP pond, a. revjsed grading plan <br />and, bydroJosi,c calcuJfl.tion's are required demoDBtra,tin.g sufficient <br />dead, ,storage for the 2.S..i.,~h event i.s provided.. If the basin is to <br />funet~onas a biofiltration feature, a. revised, grading plan. and wa.ter <br />quality treatment calcul.a.tions are reqWred demonstrating equivalent <br />NURP removal effl.ciencies of 90% TSS and 60% TP and .2. cr05S~ <br />section. "detail providing aft und.erdrai,n tOt the feature, llmetl.ded SQil <br />ami appropriate native plant Hst or seed mix. Addit'i.on.8.lly, an.outl.et <br />detail for the proposed basin demODBtratUl.g sldmm,ing capability up <br />to the 1 ~yoar event. required. <br /> <br />The submitted geotoehn.i.cal soil lmrings indicate c],s,ys throughout <br />the site and a low water tabJ e. Therefore, the bio1ntration is an <br />acceptable BMP in. J.ico of infiltration. Tbe biofiltratf.on. basin <br />proposed in the northern. portion. of th.e site is sized to satisfy thl:l <br /> <br />Emmons & Olivier Resources, Jnc. <br /> <br />-4- <br /> <br />7/29/05 <br /> <br />.:57 <br />