07/11/2007 P&Z Packet - Laserfiche WebLink

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Grandview Page 3 May 23, 2007 Drainage Review City of Lino Lakes, Minnesota 05/23/07 This item has been addressed. 13. Update the high water level labeled on the Utility Plan for the proposed pond. 05/23/07 This item has been addressed. 14. Include a curve number of 100 in the HydroCAD model for areas with open water. 15. All City maintained storm sewers, including pond outlet structure pipes, are required to be a minimum of 15 inches in diameter. 05/23/07 The pond outlet pipes are required to be a minimum of 15 inches in diameter. All city maintained storm sewer is required to be RCP. 16. Include notes on the Plan incorporating the following: 1) the infiltration area should not be excavated to final grade until the contributing drainage areas have been constructed and fully stabilized, and 2) final excavation of the infiltration areas should be completed using light tracked equipment to avoid compacting the basin floor. 17. To provide a well aerated, highly porous surface, it is recommended that the soils of the Infiltration Basin floor be loosened to a depth of at least 12 inches prior to planting. 18. It is hi • hly recommended that plants be used over seed in the Infiltration Basin. Fluctuating water levels following seeding can cause seed to float and be transported downstream of the Infiltration Basin. In addition, it may take up to two growing seasons to establish the function and aesthetic value of mature vegetation using seeds. 05/23 /07 This item has been addressed. 19. Submit a copy of the NPDES permit for the City's records when available. 20. Approval from Rice Creek Watershed District (RCWD) is required. Submit a copy of the RCWD approved permit when available. Additional Comments 05/23/07 21. Provide a 6 inch minimum clearance between the top of orifice and top of weir wall in the pond outlet structure. 22. A skimmer structure is required at the outlet of the biofiltration basin. 23. Label the storm sewer sizes, inverts, and slopes on the Plan. 24. Capture and route runoff from the south end of Stagecoach Trail to the proposed biofiltration basin. 25. It appears from the Grading Plan that runoff from the proposed Stagecoach Trail may flow off -site to the north; however, the proposed drainage area map (subcatchment 4) shows the northern area flowing south and ultimately to the pre - treatment basin. Please clarify.