08/11/2004 P&Z Packet - Laserfiche WebLink

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Engineering Review Page 3 July 30, 2004 Fox Den Acres City of Lino Lakes, Minnesota 3. The Grading Plan indicates that wetlands shall be replaced at a 2:1 ratio per requirements of the Wetland Conservation Act. The Plans also must be approved by the Rice Creek Watershed District (RCWD). A permit application has been submitted to RCWD (Permit No. 04 -039, dated March 12, 2004). RCWD has determined the application to be Incomplete, pending the receipt of several additional items. All requirements of the RCWD must be met. 4. Minimum grades and slopes must be provided and shown on the Plans as follows: 0.5% for streets (including curb and gutter), and 2.0% for turfed/non -paved areas including all swales and slopes. It would appear that in some locations, the street is less than 0.5% grade. 5. Proposed house pad information, including floor elevations are provided on the Plans, including the City's requirements for floor elevations. The minimum lowest floor must be the greater of 2 feet above the HWL, 4 feet above the NWL, 4 feet above the groundwater elevation, and 1-foot above the emergency overflow. Emergency overflows are shown for the majority of site's landlocked low areas. However, the emergency overflow location and elevations must also be clearly shown for all detention areas, including newly constructed infiltration basins and stormwater detention ponds. A table providing minimum basement elevations for all properties has been provided. The grading plan also provides a house pad detail that explains the housing style and proposed finish grade elevations. It should be noted that the detail specifies that for Walkout homes the finished basement floor is to be 0.3 above the elevation provided on the grading plan. The table figures do not reflect this for many of the properties, and should be adjusted accordingly. At least some of the proposed units do not appear to meet the minimum 4 feet separation from the NWL and groundwater elevations, based upon the mottling information provided. These include Lot 3, Block 5; Lot 3, Block 3 and Lots 18 and 19 Block 3. It is strongly recommended that all house pad elevations again be reviewed and adjusted accordingly. The Grading Plans shall also specify that all house pads on filled areas shall be designed by a registered Professional Engineer (per geotechnical recommendations) and approved by the City of Lino Lakes. 6. A Certified As -built Survey shall be provided by the Developer's Engineer upon completion of grading, certifying that all grading complies with the Grading Plan. This Certification shall be required prior to the issuance of any building permits. Final certification that the grading meets City requirements for adequate drainage and minimum slopes will be required prior to the issuing of building permits. Percent grades shall be shown on the Plan. 7. Revised drainage calculations and drainage area maps have been received and reviewed. Comments are as follows: a) As stated in the previous review, the discharge rates from the proposed 2 -,10 -, and 100 - year design rainfall events cannot exceed the existing discharge rates. The two year design as submitted does not meet this requirement. It is recommended that a discharge rate comparison table be prepared and provided, showing the revised discharge rate calculations.