08/13/2003 P&Z Packet - Laserfiche WebLink

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Engineering Review Page 5 August 8, 2003 Sportatorium Commercial • Development Site 3. Permanent easements with access availability will be required for all stormwater ponds and conveyance systems not located within the public right -of -ways. 4. A Sedimentation and Erosion Control Plan must be provided. In addition, a Storm Sewer Plan must be provided that shows all storm sewer design, including pipe and structure sizes and standard details. Further stormwater review comments are as follows: 1. The 2- and 100 -year storm computations were submitted. The 10 -year storm computations also need to be submitted. 2. A labeled proposed condition drainage area map and routing diagram must be submitted that coincides with the calculations. 3. The existing condition time of concentration does not appear to be correct. A total flow length of greater than 300 feet is given, while a measurement of closer to 1,000 feet is apparent. 4. Location of Erosion Control devices need to be shown on the site Grading Plan. 5. Flood elevations must be shown on the Grading Plan for all pond and wetlands. M6. The City must determine if required existing condition computations are to be based upon fallow conditions versus row crop conditions. Curve numbers would be closer to pre- disturbance conditions of the site. 7. A detail is required for the proposed outlet structure and emergency overflow. A skimming structure shall be required, preferable a reverse grade outlet per City standard detail. 8. The stormwater calculations and design essentially provide for development of the Sportatorium facility itself, which encompasses a relatively small percentage of the entire 40 -acre site. It is recommended that a Stormwater Management Plan be developed that considers ultimate development of the entire 40 acre site. This may be advantageous from the standpoint of limiting or eliminating the need for constructing additional detention facilities as development occurs piece by piece. A "regional" detention facility for the entire site could potentially be constructed to eliminate or reduce future constructions and costs. 9. A wood stormwater "Weir Detail" is shown on Plan Sheet D1. Wood weirs are not allowed in the City of Lino Lakes. Also, please identify the location of control structures on the construction Plans and Site Grading Plan(s). •