#11 - Drake and DQ Preliminary Plat and PUD

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PAGE 4 of 4 3. The SWMP will be required to verify that rate control and volume control requirements are met for all points of discharge from the site, and for each phase of the subdivision build‐out. The existing and proposed drainage exhibits must be revised to label all points of discharge from the site. The SWMP rate control summary tables must reference each discharge location independently and combined using the same labeling as depicted on the exhibits. SWMP revisions are necessary to provide rate control for all points of discharge and for all storm events. 4. Soil borings are required in accordance with the City Engineering Design Standards Manual dated January 2022 to determine the design infiltration rates. Borings must be taken as part of the SWMP submitted for preliminary and final plat and must be taken within the foot print of the proposed basin.  Infiltration rates used for design purposes must be based on actual soil borings taken within the proposed BMP footprint. Soil borings are required in the number and depth as outlined in the City Engineering Design Standards. Geotechnical reports must provide analysis and recommendations on proposed design infiltration rates.  The assumed infiltration rate for the proposed underground infiltration system must be revised to be at a rate of 50% of the recommended infiltration rate based on actual soil borings.  A soil boring map must be included in the Geotechnical Reports and overlaying the proposed improvements to detail soil boring locations relative to the proposed BMPs. 5. The SWMP must be revised to provide a summary table of all proposed site BMPs necessary to provide storm water management for the Project. The table must label each BMP consistent with the project plans and must identify the 100‐year HWL elevation for each BMP. 6. The storm water facilities constructed for this development should remain privately owned and maintained. The applicant will be required to execute and record a Stormwater Maintenance and Easement Agreement in the City’s standard form of agreement. The grading plans must indicate that the storm water basins are “Privately Owned and Maintained” and to include the drainage and utility easement areas. 7. The grading plans must be revised to show all emergency overflow (EOF) locations and elevations for all BMPs and localized low areas. All EOFs and flow pathways must be protected by easement. 8. Revise the storm sewer layout as necessary to maintain all discharge velocities to be less than 5 fps. The storm sewer calculations show FES 200 at 10.3 fps and FES 300 at 6.3 fps. The Dairy Queen storm sewer calculations show the FES discharge to be 6.41 fps. Storm sewer calculations must be updated to include all proposed storm sewer pipe runs. The diary queen store pipe discharge 9. Revise the storm sewer pipe from CBMH‐202 to MH‐201 to be minimum 15‐inch RCP. 10. Revise the DQ storm sewer pipe run from STMH 109 to FES to be minimum 15‐inch RCP. MUNICIPAL WATER AND SANITARY SEWER 1. Public watermain and sanitary sewer are available to serve the subdivision with existing utilities located in the Hudson Boulevard right‐of‐way. The developer will be responsible for all costs to extend utilities within and throughout the subdivision to fully serve each proposed lot. 2. Hydrant locations and system valves must be placed internal to the site as directed by the Lake Elmo Public Works and Fire Departments. Plan and easement revisions will be required accordingly. All internal site hydrants, and watermains feeding any hydrant, will remain city owned and operated. Minimum 30‐ foot easements centered over the pipe/hydrant will be required without encroachments. 3. The watermain and sanitary sewer plans must be revised to specify the public watermain and public sewer mains vs. the “begin location” for each private water/sewer service to each lot. A curb‐stop or gate valve is required and the end point of the public watermain and each private service must be clearly labeled. Plan notes must be added to indicate that the private water/sewer services are to be constructed per state building code. 4. The applicant has indicated that the estimated WAC and SAC units for the subdivision include 19 WAC/SAC units for the auto service and office, 10 WAC/SAC units for the restaurant, and an additional 30 WAC/SAC units for the future development of Lots 2 and 3, Block 2. In addition, the estimated fire flow demand has been reported to be 1,200 GPM for a 4‐hour duration.