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HomeMy WebLinkAbout1979-04-19 BRAA Ltr to OPH e0 1 ._, Rte, 4Kda* 444C&td, 9.w. e� 'em 2335 W. 14iw4 #iyluualj 36 Otto G. Bonestroo, P.E. Lawrence F. Feldsien, P.E Robert R'. Rosene, P.E. Glenn R. Cook, P.E. /� � 4 /haul, Af4use 4 55113 Joseph C. Anderlik, P.F. Keith A. Gordon, P.E. /�df0/i6: 636 —�60� Bradlord A. Lemberg, P.E. Thomas E. Noyes, P.E. Robert D. Frigaard, P.E. Richard W. Fnster, P.E. Richard E. Turner, P.£ Robert G. Schunicht, P.E. James C. Olson, P.E. Marvin L. Sorvala, P.E. Donald C. Burgardt, P.E. Kenneth R. Meister, P.E. April 19, 1979 Charles A. Erickson Leo M. Puwelsky Harlan M. Olson City Council City of Oak Park Heights 14168 - 57th Street No. Stillwater, Mn. 55082 he: St. Croix Mall Surface Drainage Study City of Oak Park Heights File No. 55 Gentlemen: We have studied the surface drainage runoff and collection facilities for the St. Croix Mali property owned by Swager 3 as requested and submit the following infrormation and recommendations: 1. South Side The existing storm sewer was found to be of adequate size to handle the surface drainage generated by a 2" per hour rainfall. The existing line should be extended, however, as indicated on the K -Mart Plan to complete the south area system. 2. Northwest Area The northwest area includes part of the K -Mart area, part of the Bowling Alley area, the VFW Club, Kentucky Fried Chicken and the adjacent parking lot areas. This area is approximately 5.8 acres and the runoff caused by a 2" per hour rainfall will be approximately 11.03 cubic feet per second (11.03 c.f.s.). The surface drainage from this area flows toward T.H. 212 down the IJ.W. entrance drive. This plan will produce a depth of flowing water of approximately lZ ". While this runoff can be adequately handled in this manner, good design procedures would install an 18" R.C.P. pipe at 1% grade running from the storm sewer on the service road to the point where the entrance drive meets the parking lot and there placing two catch basins, one on each side of the entrance road, to intercept the surface water runoff. 3. Northeast Area The northwest area includes a part of the main building, the greater part of the north parking lot and one -half of the bank. The area includes approximately 4.6 acres. Here, as in the northwest area, the runoff is strictly surface drainage until it reaches the service road on T.H. 212. A 2 per hour rainfall in this area will generate a flow of approximately 8.7 cfs. Page 1. Y ` V • City of Oak Park Heights April 19, 1979 Stillwater, Mn. 55082 Re: File No. 55 Again while this water can flow down the northeast entrance road good design practice would require the installation of a 15" RCP pipe at 1.5% grade. Two catch basins should be installed at the junction of the entrance road and the parking lot to intercept the runoff before it enters the entrance road. The preceding information covers the surface water runoff for the St. Croix Mall area. It is recommended that the storm sewer lines and catch basins discussed previously be installed to handle the north side of the area for the benefit of the Mall customers, the owners and the City, and to prevent possible erosion problems. If there are any questions on this matter, please feel free to contact our office. Yours very truly, BON, STROO, ROSENE, ANDERLIK & ASSOCIATES, INC. �"` ( eim Bradf rd Aberg, P.E. BAL:li j cc: Swager Bros. Page 2.