12-08-1997 Council Packet - Laserfiche WebLink

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i I I 1 BONESTROO AND ASSOCIATES Bonestroo Rosene Anderlik & Associates Engineers & Architects November 13, 1997 Ms. Eli7.abeih Van Zomcioii Cily Planner/Zoning A»iniini.sirator City of Orono P«)5I Office Bon 66 Crystal Bay. Minnesota 5332.3 Re. Lake Minnelonk.i Woi>d.s File No. I39-2.10H ^612 6361311 11/1A/97 10:33 l3 :02/02 N0:162 »«a .»•»./ 9.i »f»*» »»»* •%.«#» r f » • I </• •• • i> * | I It Is* ^ ’ H« u If* •. •' . 1*1 • ti • ' <A M« Jr • «.a 1*^ • V *i » •*’ < • * »i « ’• ► • 1^1 • •',fr*i.ir f si,'!* fl a bi.ftr.'l IS T'iifSit n» I I • A Hntii'Jk fi ♦ ► • M Wr*.c*'r »'l <||||1 M ►rn»lifi i mA. *rrn,n l .^n-.iiif tf i(« i*.i A .1 l*L • Rc'lh A m »'► t .P*M f| I. 'U i*» • \Af Fii'.U-i. Hb • O.iv 111 «) • |A • M.i»* A M.tmoii |'f • Ml» Mflifl T iJ.UltiM.efSM I’l a Iril Kf*r<>l • ► • amr>* jn h AiVJi i wil N PllUS Kb # P Vi'ilN Hiijufs Kb I \ • W'»0r'l ► *t .||in |r rf'br,,*., Cf A‘i.»r*i»tr» v4/*'i**i*«' .'I'*} S’ ( M.% • A!..vs •««ai . \l> i Dear Liz. We have reviewed the rcsiacd preliminary construction plans for the proposed Lake Minnetonka Wood.s planned residential devciopmeni consisting of 30 townhomes. The site is located on Lob 2 and 3 and the west 6.29 feet of Lot 4, Block 9. Townsiic of Langtion, along the north side of CSAH 15 We have the following comments in regards to engineering nuaicr.s. 1 UtUitiaa: The sanitary sewer and water main designs appear acceptable from an engineering standpoint. Details should be provided with ilic final plan set Our expectation is that Livingston Avenue will be extended westcily sometime in the future We would recommend extending the sanitary and water main stubs to the west property line as port of this project. .Service loeHiions should be shown on the final plans with sanitary serv ices located 3 feel downstream from watci services 2, Drainage: The drauunjc area map should include the boundary for flows to the nonherly wetland and CB 33 to verify that the proposed 12-inch RCP under Livingston Avenue is adequate. The 20 minute time of concentration used for some of the CHlculaiu»ns scorns high for this site. We would recommend revising the storm sewer and ponding calculations lor tlcvcloped conditions using a maximum lime of concentration of IS minutes. Pipe grades and / or pipe siecn |>ctwcvn CB32 and STMH 31 may need to be rcvisetl. A paved swale or some type of erosion control measure should he provided at the downstream end of the ft-inch HDPH pipe. Details of the pond outlet control structure and bullied wcir should be provided for review. The limber weir may be a future maintenance problem. The City muy wani to consider nn uliernaiivo outlet structure design without the weir where skimming is provided by a .submerged mlci pipe to the structure. 3. Streets: 'ITic 19 units being served by the temporary cuLde-sac on Livingston Avenue exceeds the maximum of 10 units allowed by City si.indards. The horizontal alignment proposed for Livingston Avenue does not meet the City standard for 30 mpli design. The radii should be increased to 275 feet or reduced speed warning Signs installed. All propo.scd vertical cuiuis do meet the 30 mph design standard. We would recommend that Livingston Avenue be consuucicd 10 ihe wesicily lui line as part of this project. The proposed driveway to serve the 11 units on Blocks ^ and 4 docs not meet any of the City design .standards for private streets relative to right-of-way width, minimum paved width or muxinuim nmnlK'r of units on a cul-de-sac. Emergency vehicle access to those units un Blocks 3 and 4 will be a problem omi tin City should review the plan.s with the appropriate emergency officials. Typical street sections should he provided lor Livingston Avenue and the private drive. A gcotechnicol analysis and R value recommendaiinn should he suhmilted to verify the proposed pavement design. Please contact me at 604 4h(>3 i I you have any questions regarding this matter. Yours very truly. DONF..STROO. ROSENl .. ANDERLIK. & ASSOCIATES. INC. /Oryyl Tom Kellogg 2335 West Highwity 36 • St. Paul. MN 55113 • 612-636*4600 • Faw