04/19/2014 P&Z Packet - Laserfiche WebLink

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Ms. Katie Larsen April 2, 2014 Page 2 Sanitary Sewer and Watermain Comments: 1. The location of the proposed garages needs to be added to the plans so that we can confirm that the house services will not be located in the driveways. It currently appears that Lot 10 Block 3 would have the utilities located within the driveway. 2. The proposed 8-inch watermain loop along Sunset Road needs to be extended further south and connect into the existing watermain located at the intersection of Century Trail rather than constructing it east across Outlot C as currently shown. 3. The existing private well shown on Lot 7, Block 4 needs to include a note that it needs to be properly abandoned. 4. It appears that the house pad on Lot 10, Block 3 is not within 250 feet of a proposed hydrant. Revise the hydrant spacing so that all of the house pads will be entirely within 250 of a proposed hydrant. Storm Sewer and Drainage Comments: 1. The alignment of the storm water pipe outlet for the pond located in Outlot B needs to be revised so that it is not discharging into the existing ditch at a 90 degree angle. The discharge pipe should be angled so that the flow is more in line with the ditch flow. 2. All of the proposed storm sewer that is shown between lots will require a minimum of 10- feet of drainage and utility easement on either side of the pipe. Currently, the drainage and utility easements shown vary in size from 5-feet to 7.5 feet on either side of the pipe. 3. Storm sewer design calculations must be provided for review and approval prior to final plat approval. Profile drawings of public utilities will also be needed with this submittal. 4. Design must be revised so that proposed peak discharge rates do not exceed existing peak rate for the 100-year, 24-hour event. 5. Verify proposed outlet design provides a water quality release rate of less than or equal to 5.66 cfs/acre of pond surface area, per MPCA Construction General Permit requirements. 6. Curve Numbers used in the HydroCAD model should match standards outlined in RCWD Rules. 7. Site area in the Drainage Report does not match the areas given on the Stormwater Pollution Prevention Plan Sheet (10.8 acres versus 16.98 acres). 8. Verify the total runoff area as the HydroCAD output shows an increase from existing to proposed conditions, while the watersheds shown on plans did not change. 9. The total new impervious/disturbed impervious area contributing to Pond G (288,401 square feet) is more than the project total new/disturbed impervious area (220,600 square feet). 10. Proposed culvert not shown in HydroCAD model, please provide culvert design calculations. Grading Comments: 1. The grading plans identify locations in a number of the back yards as Emergency Over Flows (EOF), but they are actually high points. For example there are EOF's identified between Lots 6 & 7, Block 3, behind Lot 10, Block 3, behind Lot 1 Block 4, behind Lot 6, Block 4, behind Lot 1 Block 2, between Lots 4 & 5, Block 1. 2. The locations of the soil borings is shown on the grading plan but the actual borings were not provided. The soil boring reports needs to be submitted for review.