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August 23, 2024 Page 2 14. Include provisions within the construction documents to ensure that the native soils infiltrate as planned for in design prior to installing the chamber system. Recommendations for permeameter tests for designed are available in the Minnesota Stormwater Manual Design Criteria for Infiltration. 15. As required by City Ordinance No. 141, Section 22.2.3.11, include a diversion or other method within the construction documents to keep construction site sediment from entering an infiltration and/or filtration system prior to final stabilization of the entire contributing drainage area. 16. As required by City Ordinance No. 141, Section 22.2.3.11, include provisions within the construction documents that will prohibit construction equipment from compacting the soils where infiltration and/or filtration practices are proposed. 17. Consistent with item 16.8 of the Minnesota Pollution Control Agency’s Construction Stormwater Permit, Permittees must design the infiltration system to discharge all stormwater (including stormwater in excess of the water quality volume) routed to the system through the uppermost soil surface or engineered media surface within 48 hours. Permittees must route additional flows that cannot infiltrate within 48 hours to bypass the system through a stabilized discharge point. Revise system as needed. 18. Consistent with item 16.9 of the Minnesota Pollution Control Agency’s Construction Stormwater Permit, Permittees must provide a means to visually verify the infiltration system is discharging through the soil surface or filter media surface within 48 hours or less. Comment on the means of verifying drawdown. 19. Provide maintenance access to all components of the proposed treatment system. Identify in the maintenance plan how access will be achieved, and any special considerations needed to access the subsurface system. 20. Prepare a maintenance agreement and maintenance plan as described in City Ordinance No. 141, Section 22.2.5. 21. Revise HydroCAD models such that the total area is consistent between existing and proposed models. 22. Provide a cross section of the infiltration system, as designed, including pre-treatment chambers, weir walls, standpipes, etc. 23. Ensure pretreatment chambers have a starting water elevation in models. 24. Provide justification that exfiltration applied over surface area is appropriate for perforated pipes. 25. Additional comments from RWMWD a. See Attachment 1 DJC X:\FJ\G\GEMLK\Common\Kia Development 2024\Barnett Kia SEH Review Memo_8-23-24.docx