02/14/2007 P&Z Packet - Laserfiche WebLink

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Comforts of Home Development Page 3 January 8, 2007 Drainage Review City of Lino Lakes, Minnesota 8. 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 24 inches, and the upper 10 inches of soil be tilled prior to planting. 9. As of HydroCAD 7.0, the peak elevation must not exceed the defined storage of the pond. Update Pond INF -1 to ensure that the peak elevation is below the defined storage. 10. The Grading Plan indicates that the water elevation of the existing wetland was at an elevation of 899.1 on May 3, 2006; however, the normal water level of the wetland was modeled at an elevation of 898 under existing conditions. Please clarify why the normal water level elevation in the model was not set at the observed water elevation. 11. The curve number for the off -site area to the north is inconsistent between the existing and proposed conditions model. Update the model for consistency. 12. The existing curve number for subcatchment EX -B is 67, brush in poor condition. Aerial photographs suggest that the site is a combination of woodland and open pasture area. Please clarify the curve number used in the model for existing subcatchment EX -B. 13. The curve number and total area for subcatchment PR -4 and the off -site area in subcatchment EX -A is inconsistent. Update the model for consistency. 14. Provide calculations demonstrating that PR -1 and PR -2 is only 65% and 75% impervious, respectively. • 15. A curve number of 100 should be used in the existing and proposed models to represent open water conditions. 16. Ensure that all pond outlet structure inverts as modeled are consistent with the pond outlet structure inverts labeled on the Utility Plan. 17. Submit storm sewer design calculations for review when completed. All storm sewers, including pond outlets, are required to be a minimum of 15" diameter pipes.