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Ms. Katie Larsen <br />10/31/2025 <br />Page 3 <br />7920 Lake Drive – Lino Lakes Dealership – Engineering Review <br />*Existing condition is the updated modeling of the regional drainage system with assumed <br />developed landcover <br /> <br />Comments: <br />1. The proposed parking lot grading must be revised to raise it above the regional pond <br />HWL of 906.53. <br />Plowe (10/21/2025) HWL in Basin 1 contained within basin footprint. <br /> <br />2. CBMH 3 needs a sump to provide pretreatment of inflows to INF-1. <br />Plowe (10/21/2025) Sumps added to two upstream catch basins <br /> <br />3. Rolled erosion blanketing containing natural netting is needed on proposed 3:1 <br />slopes. <br />Plowe (10/21/2025) Note added to Sheet 2.2 (trail grading). <br /> <br />4. Riprap stabilization is recommended instead of matting for INF-2 basin overflow. <br />Plowe (10/21/2025) Basin 2 has been removed <br /> <br />5. Native vegetation must be shown over proposed infiltration BMPs and their side <br />slopes in the landscaping plan. <br />Plowe (10/21/2025) Noted; Seed mix 33-261 used <br /> <br />6. Trees should not be planted in the infiltration basin. <br />Plowe (10/21/2025) Trees removed from basin. <br /> <br />7. Exfiltration must be removed from the modeling for determination of site rate control <br />and HWLs. <br />Plowe (10/21/2025) Removed from latest models <br /> <br />8. HydroCAD modeling should use the separate impervious/pervious runoff mode in <br />model settings for most accurate hydrology. <br />Plowe (10/21/2025) Noted; current modeling is the most conservative (higher rates, <br />higher HWL) <br /> <br />9. Revise storm sewer to collect more of the surface flow from the eastern half of the <br />parking area. <br />a. Currently all surface flow goes to the southeast curb cut <br />Plowe (10/21/2025) Attempts were made to collect as much runoff in the storm sewer <br />system such as the revisions of parking lot grades and decrease in impervious cover. <br />Due to cover requirements, final inlet elevation for DLI surcharge requirements, etc. a <br />rain guardian is necessary at the low corner (higher than the HWL) so an additional <br />rain guardian was added so the surface runoff can be handled adequately. <br />WSB (10/29/2025) Complete <br /> <br />10. WSB (10/29/2025) Shift 8” storm sewer on the south side of the building such that it <br />meets minimum 1:1 slope requirements from the existing easement line. <br /> <br />11. WSB (10/29/2025) Recommend combining storm sewer prior to outfall to INF-1 per <br />markups on plans. Also recommend shifting CBMH-3 to the north curbline rather than <br />within the driving lane. <br /> <br /> <br /> <br />Page 36 of 406