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HomeMy WebLinkAboutRe: grading (2) Bonestroo,Rosene,Anderlik and Associates,Inc.is an Affirmative Action/Equal Opportunity Employer Bonestroo Principals:Otto G.Bonestroo,P.E.•Joseph C.Anderlik,P.E.•Marvin L.Sorvala,P.E. Richard E.Turner,P.E.• Glenn R.Cook,P.E.• Robert G.Schunicht,P.E.• Jerry A.Bourdon,RE. RoseneRobert W Rosene,PE.and Susan M.Eberlin,C.P.A.,Senior Consultants Associate Principals:Howard A.Sanford,P.E.• Keith A.Gordon,P.E.•Robert R.Pfefferle,P.E. Anderlik & Richard W.Foster,P.E.•David O.Loskota,P.E.• Robert C.Russek,A.I.A.•Mark A.Hanson,P.E. Michael T Rautmann,P.E.•Ted K.Field,PE.• Kenneth P.Anderson,P.E.•Mark R.Rolfs,P.E. Associates Sidney P.Williamson,P.E.,L.S.• Robert F Kotsmith Offices:St.Paul,Rochester,Willmar and St.Cloud,MN• Milwaukee,WI Engineers &Architects August 15, 1997 Mr. Michael P. Gaffron Asst. Planning and Zoning Administrator RECEIVED City of Orono Post Office Box 66 AUG 8 1997 Crystal Bay, Minnesota 55323 Re: Dennis Meyer File No. 139-2257 Dear Mike, We have reviewed the grading plan for the proposed residential home construction for Dennis Meyer on Tract F at Tonkaview Lane. The grading plan is acceptable from an engineering standpoint. Due to the increase in hardcover and the existing severely steep slopes immediately south of the proposed residence, we would recommend that the applicant construct a storm water quantity pond. The pond would function as a dry pond, used only to reduce post-developed peak flows to existing conditions. We have estimated the drainage area to the pond at 0.7 acres. We recommend that the pond be graded approximately 25 feet in diameter, with a two foot depth, 3 to 1 slopes (max.), and a 6-inch outlet culvert. These specifications would reduce the developed peak flows to existing conditions. The approximate elevations of the pond would be 1022 at the bottom and 1024 at the top of the berm. The culvert would extend from the bottom to daylight below the berm. The runoff would reach a depth of 1.5 feet in the pond during a 100- year storm event, assuming that the outlet is not plugged or frozen. We have attached a rough sketch of the recommended pond. Please contact me at this office if you have any questions regarding this matter. Yours very truly, BONESTROO, ROSENE, ANDERLIK, & ASSOCIATES, INC. Shawn D. Gustafson, P.E. Cc: Mr. Greg Gappa, City of Orono 2335 West Highway 36 ■ St. Paul, MN 55113 ■ 612-636-4600 ■ Fax: 612-636-1311