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HomeMy WebLinkAbout2018-09-18 Stantec Plan & Drainage Design Review Stantec Consulting Services Inc. 2335 Highway 36 West Stantec St.Paul MN 55113 September 17,2018 File:193800151 Attention: Mr.Eric Johnson,City Administrator City of Oak Park Heights 14168 Oak Park Blvd.N.,P.O.Box 2007 Oak Park Heights,MN 55082-2007 Reference: Ridgecrest—Plan and Drainage Design Review Dear Eric, We have reviewed the plans and drainage calculations submitted 9-10-2018 regarding the proposed Ridgecrest Development.Following are our comments and recommendations: Proposed Site Plan 1. Provide a commercial driveway apron per City Detail STR-8 at 601h Street North. 2. A permit will be needed from MnDOT for work in 601h Street North. 3. Refer to the Fire Department review of fire lanes and circulation. 4. Planning is in process for a potential backage road that would be located along the south side of the project. There have been preliminary drawings depicting how this site might connect to the backage road through the adjacent property to the west. While this configuration will not be included in the construction plans,please submit the concept of the potential proposed connection. Grading and Erosion Control Plan 1. Clarify the contours and the grading in the southwesterly corner of the site. 2. The directional flow arrow(6.51%)shown just north of the southerly most parking area appears to be in error. 3. Label low point's(LP's),high point's(HP's),and emergency overflow's(EOF's)on the grading plan. 4. Show the storm sewer pipe that is connected to the catch basin adjacent to the west edge of the site. 5. Remove any notes that are not relevant to this project,i.e.,is there a retaining wall on this project? 6. The City reserves the right to require additional erosion control measures as determined/necessary during the construction of the project. Utility Plan 1. Show keynote"C"at utility crossing#7. Design with community in mind September 17,2018 Mr. Eric Johnson, City Administrator City of Oak Park Heights 14168 Oak Park Blvd. N., P.O. Box 2007 Oak Park Heights, MN 55082-2007 Page 2 of 3 Reference: Ridgecrest- Plan and Drainage Design Review 2. Show the storm sewer pipe that is connected to the catch basin on the west edge of the site. 3. Flatten the sewer service line between the existing manhole and San MH#1 to increase the spacing at Utility Crossing 1 and 2. Double check your separation calculations in the Utility Crossings Locations table and include pipe thicknesses in the calculations. 4. 4-inches of insulation (minimum) shall be provided at storm sewer crossings with watermain and/or sanitary sewer when separation is three feet or less. 5. The City or it's designee shall be present for water and sanitary sewer service connections to the City's systems. Stormwater Drainage Review 1. Provide the City with the documentation of the approval and conditions from Brown's Creek Watershed District. 2. Revise the peak discharge rate tables to reflect the most recent values in the HydroCAD reports. 3. Submit storm sewer size calculations that verify the system is being designed to meet the 10-year storm. 4. The proposed MIDs model should be updated to include tree trench/rain garden T3. 5. For drainage area S5, a curb cut into the adjacent tree trenches (T1 and T2)or a catch basin should be installed to collect as much water from the road to prevent it from out falling directly onto 60th Street. Details 1. To prevent potential standing water in the rain gardens and tree trenches media, place the draintile at the bottom of the trench and slope the bottom of the trench to the draintile. General Comments 1. The City reserves the right to inspect the construction of the project. The City or its designee shall be present for water and sanitary sewer service connections to the City's systems. 2. The Owner will need to comply with all requirements of the NPDES Construction Stormwater Permit and the Brown's Creek Watershed District. The City reserves the right to require additional erosion control measures as determined/necessary during the construction of the project. 3. Parking, lighting, landscaping and building to be reviewed by others. 4. The Owner shall be responsible for obtaining all required permits. 5. Utility construction and improvements in the right-of-way need to conform to the City's Standard Detail Plates. If you have any questions or require further information, please do not hesitate to contact me. Design with community in mind September 17, 2018 Mr. Eric Johnson, City Administrator City of Oak Park Heights 14168 Oak Park Blvd. N., P.O. Box 2007 Oak Park Heights, MN 55082-2007 Page 3 of 3 • Reference: Ridgecrest - Plan and Drainage Design Review Regards, Stantec Consulting Services Inc. Lee M. Mann, PE City Engineer Phone: 651-604-4850 Lee.mann @sta ntec.corrin c. Andy Kegley, Public Works Director Julie Hultman, Building Official Scott Richards, City Planner Mark Vierling, City Attorney Lisa Danielson, City Arborist Design with community in mind