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. + <br /> pc �h��rt e <br /> B�1._TC?N � M �N K , � N C� <br /> Consulting Engineers 8t Surveyo�a <br /> 2638 Shadow Lahe,Sulte 2�•Cheske,MN 5531&1172 <br /> Phone{952)448-8838•Fax(952)448-8805 <br /> www.boRon-meMc.com <br /> August 13,20I5 <br /> City of Orono <br /> Aun: 11�ke Gaffron <br /> 2750 Kelley Pazkway <br /> Orono,:VirT 55356 <br /> RE: Sabdiv�ision Application 15-3774 <br /> 1�00 ShareJine Drive <br /> Engineering Review#1 <br /> Dear Mike: <br /> As requested, we have completed an engiacering review of thc documents subnrnitted for the above <br /> referenced project. We offer the following comments for your consideration: <br /> General <br /> l.l. A B1uff Analysis should be submitted to confirm bluff areas indicated on plans. <br /> 1.2. A Stormwater Management Analysis must be submzued to verify proposed peak runoff rates are not <br /> greater than existing rates. The new impervious surface aff-site necessary to connect ta Heritage Lane <br /> should be inc�uded in the analysis. If more than 1 acre of new unper►rious surface is pzoposed for <br /> uttimate development,in�iltration must be provided per NPDES requiremen�ts. If greatEr than 20� of <br /> the tatal site area is impervious surface,permitting from Minnehaha Creek Watershed District will be <br /> required frnr their Stormwatez Management Rule. <br /> 1.3. The proposeti storm sewer and pond layout dire�t runoff to Wetland 3 on the north side of the site. <br /> Wetland 3 outlets through a aazrow swale on H�nepin County Regional Railroad Authority{HCRRA) <br /> property to Tanager Lake. Since the outlet for Wedand 3 is fairly narrow,potential fc�r clogging of the <br /> o�tlet awale eaists. Alsa,since the outiet for Wetland 3 is located on HCRRA propercy off the far <br /> northeast corcier of die site,the out�et swale will be inaccessible for nnaintenance if it does become <br /> clogged. Therefore,the proposed pond should oudet through a swale constructed between lots 1 and 2, <br /> throngh Wetland 2. Additional tree removal and grading may be necessary to clefine a swale from the <br /> pond to Tanager i.ake. AddidonaI fflling of Wetland 4 at t1�e street crossing may be necessary to <br /> provide adec�uate slope from sewer to poad to Wetland 2. <br /> 1.4. The proposed stormwater pond should be reconfigured to minimize tree removal. By moving the pond <br /> cIoser to the proposed road,less tree removal should be necessary ta canstract storm sewer,pond,and <br /> outlet swaIe. <br /> 1.5. In order to conscruct tlte street exteasion from Heritage Lane,temporary construction easements may <br /> be necessary from adjacent property owners. A,ny easements necessary should be submitted to City <br /> prior ta Final Plat apgroval. <br /> 1.6. Retaining walIs are proposed in the right-of-way of Heritage Lane at the conneition to the existing <br /> street. The following should be considered regazding these walls: <br /> a. Additional detail should be provided frnr the retaining walls. Spot elevations should be provided at <br /> key lacations (i.e.changes in vertical and horizontat alignment). Walls 4' or greater in height must <br /> be designed by a licensed Professional Engineer,and plans must be snbmitted to the City for <br /> review and approval prior to construction. <br /> b. Adequate clear space should be provided between street and walIs for snow removal and fire <br /> fighting operataons. Wall locations shauld be reviewed by Public Works and the Fire Chief. <br />