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� J ] <br /> PC Exhibit E <br /> BO�TC'�N $�. I\/I �N K , I NG. <br /> Consulting En�ineera 8� Surveyors <br /> 2638 Shadow Lane,Sulte 200•Cheske,MN 5531&1172 <br /> Phone{952)448-8838�Fax(952)44g�.ggp5 <br /> www.bofton-menk.00m <br /> August 13, 2015 <br /> City of Orono <br /> Attn: Mike Gaffron <br /> 275Q KelIey Pazkway <br /> Orono,MN 55356 <br /> RE: Subdivision Application 15-3774 <br /> 1700 Shareline Drive <br /> Engineering Review#1 <br /> Dear Mike: <br /> As requeated, we have completed an engineering review of the documents submitted for tfie above <br /> referenced project. We offer the following comments far your consideration: <br /> eneral <br /> 1.1. A Blu,ff Analysis should be submitted to confirm bluff areas indica[ed on plans. <br /> 1.2. A Stormwater Management Analysis must be submitted to verify proposed peak runoff rates are nat <br /> greater than existing retes. The new impervious surface off-site necessary to connect to Heritage Lane <br /> shouId be included in the analysis. If more than 1 acre of new impervious surface is propose�for <br /> ultimate development,infiltration must be provided per NPDES requirements. If greater than 2Q96 of <br /> the total site area is iu�perviaus surfac:e,permitting from Minnehaha Creek Watershed District will be <br /> required for their Stormwater Managennent Rule. <br /> 1.3. The proposed storm sewer and pond layout direct runoff to Wedand 3 on the north side of the site. <br /> Wetland 3 oatlets through a narnow swale on Hennepin County Regional Railroad Authority{HCRRA) <br /> property to Tanager Lake. Since the oudet fot Wetland 3 is fairly nazrow,potential for clogging of the <br /> outlet swale exists. Also,since the oudet foz Wetland 3 is located on HCRRA propezty off the far <br /> northeast comer of the s�te,che outlet swale will be inaccessible for maintenance if it does become <br /> clogged. Therefore,the proposed pond should outlet through a swale constructed between lots 1 and 2, <br /> through We#land 2. Additional tree removal and grading may be necessary to define a swale from the <br /> pond to Tanagez Lake, Additional filling of Wetland 4 ai the street crossing znay be neoessary to <br /> pro�ide adequate slope from sewer to pond to Wetland 2. <br /> 1.4. The proposed stormwater pond shouId be reconfigured ta minimize tree removal. By moving the pond <br /> closer to the propose�road,less tree removal should be necessary to construct storm sewer,pond, and <br /> outIet swale. <br /> 1.5. In order to construct the st�eet extension frnm Heritage Lane,temporary construction easements may <br /> be necessazy from adjacent property owners. Any easements necessary should be submitted to City <br /> prior to Final Plat approval. <br /> 1.6. Retaitning walls are proposed in the right-of-way of Heritage Lane at the connection to the existing <br /> street. Tt�e following should be considered regard,ing these wal�s, <br /> a Additional detail should be provided for the retaining wal�s. Spot elevations shonld be provided at <br /> key locations (i.e.changes in vertical and horizontal alignment}. Walls 4' or greater in height must <br /> be designed by a licensed ProfessiQaal Engineer,and plaaas must be submitted to the City for <br /> review and approval prior to construction. <br /> b. Adequate clear space should be provided between street and walls for snow removal and fire <br /> figb.ting operations. Wall locations should be reviewed by Public Works and the Fire Chief. <br />