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

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Holiday Stationstore Page 2 January 31, 2007 Drainage Calculation Review City of Lino Lakes, Minnesota 4. Indicate the pipe size, slope and invert elevation of the existing pipe the discharges to the 35W right - of -way on the Plans. 5. Label the inverts of all flared end sections on the Plans. 6. All City- maintained storm sewer, including pond outlet structure pipes, are required to be a minimum of 15 inches in diameter. 7. The storm sewer design may change due to modifications of proposed curve numbers based on comment 3 (significant issues) above. The storm sewer design will be reviewed when the updated calculations are re- submitted. 8. Indicate the overland emergency overflow location and elevation of all ponds and parking lot /road low points on the Grading Plan. Low openings are required to be a minimum of 1 foot above the emergency overflow elevation. 9. Provide a cross - section detail of the infiltration basin on the Plans that includes information such as the depth and type of soil mixture. 10. Label the high water level of the infiltration basin on the Plans. 11. Include notes on the grading plan incorporating the following: 1) the proposed infiltration area should be staked off and marked during construction to prevent heavy equipment from compacting the soil, 2) the infiltration area should not be excavated to final grade until the contributing drainage areas have been constructed and fully stabilized, and 3) final excavation of the infiltration areas should be • completed using light tracked equipment to avoid compacting the basin floor. 12. To provide a well aerated, highly porous surface, the soils of the infiltration basin floor should be loosened to a depth of at least 12 inches prior to planting. 13. Indicate the type and location of vegetation used in the ponding areas. It is highly recommended that mature 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. 14. The MPCA NPDES Permit requires that the design storm runoff volume in the proposed infiltration basin infiltrate within 48 hours. 15. Submit a geotechnical report for review. The lowest floor elevation is required to be 4 feet above the seasonal high ground water elevation. 16. Runoff from the site discharges to the Interstate Highway 35W right -of -way; therefore, permit approval from Mn/DOT may be required. 17. Submit a copy of the NPDES permit for the City's records when available. 18. Approval from Rice Creek Watershed District (RCWD) is required. Submit a copy of the RCWD Permit when available.