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m9 euua ioi la OUI1CO I l\UU l^woeiui ni1A4C.r%k. A IN M%J4WWWAWAA r • ^ <br />Memo Bomstfoo <br />4 <br />Pn^md Hmmm: Navarre Kingdom Hall <br />To: TomKallogg <br />From: Earth Evana <br />Rm: Stormwater Review <br />CItont: CityofOrono <br />HloNo: 139-0&^}00 <br />Oafe; 5.5.05 <br />Development: <br />Engiiwen <br />Submittal: <br />Date of Plane: <br />Navarre Kingdom Hall <br />Pioneer Development <br />Drainage Calculations, Drainage and Grading Plans, Wetland Delineation Report <br />4.18.05 <br />aiiiwmerv ftf ByBft pimandatione <br />Based on the stonnwater review of Navarre Kingdom Hall, we offer the following comments. Details for each <br />reconunendation follow. <br />1. Ofif-eite drainage should be included in calculations and shown on plans. <br />2. Adequate water quality treatment has been provided. <br />3. Proposed discharge rates are slightly higher then pre-development rates for the 1,10 and 100-year evens. <br />Based on USOS mapping it appears that the entire site eventur lly outlets via the 12 ” culvert under Togo Road to a large <br />^i^rtI^g wetland. All off-site drainage must be included in die calculations and plan set in order to rnsure that the pond <br />and low point south of Togo Road ftmetion as designed for water quality and quantity purposes. Off-site drainage to the <br />low point was included in the developer’s engineers H^droCad modeling, but not for the south pond and adjacent wetland. <br />The low point storage shown on the plan doesn’t coiresponi with the liydrocad modeling. ’> his should be confirmed <br />considering its proximi^ to the entry drive. <br />amt <br />The majority of the impervious on-site is routed south to the proposed pond. Adequate wet volume has been provided in <br />the pond to treat the 2.3-inch event We recommend louting the entirety of the proposed building south to the pond via <br />roof drains since m water quality treatment is provided in the low qiot south of Togo. <br />We recommend peoviding a 10-foot aquatic bench at 10:1 below the NWL of the proposed pond. <br />Su-wO there is mininud proposed inqiervious for the north side of the site, no existing and proposed discharge coiiqiatison <br />was iMde. The primary change fifom pre-development condition discharge rates is due to the additional impervious on the <br />south side of the site. The following tidile lists the existing and proposed discharge rates from the south side of the site. <br />Scenario 2-yeor Oucharge <br />(eft) <br />lO-yesr Discharge <br />(Cf8) <br />lOO-year Diicbarge <br />(Cf8) <br />Existina 0.1 1.7 4.2 <br />Proposed 0.4 2.3 3.3 <br />sasswMiHWNMyss isiswmim^nmmi <br />Bl PUS. MN 8611* <br />PsKesi 1S11 <br />PIniw: asa-341 <br />F«c aea>s4i-4eoi <br />11* 7* SIM NE <br />woch Mf. MN sesoe <br />ManK S07-2S2-2100 <br />F«c sor-ae2-3iao <br />znssisiMsw <br />WHm, MN 66201 <br />Plwiw; 33O4M4-S0J7 <br />F«C 320-214-066S <br />3721 23*SIM8 <br />St Cloud. MN 86301 <br />Pnono; 3*0.*8i.4as3 <br />F«c 320^1-6262 <br />OfliyMako. It 60030 <br />Ptanv 847-846-6774 <br />Fwc 847-846-6878