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08.b3 Engineer Comments^Tii Gavo- October 202214727 209 t h St. N. PO Box 128, Scandia , Minnesota 55073 Phone (651) 433 -2274 Fax (651 ) 433 -5112 h t t p://www.ci .sc andia.mn.us October 3, 2022 Brenda Eklund City Clerk 14727 209th Street N Scandia, MN 55073 RE: Tii Gavo Second Addition Review Dear Ms. Eklund We have completed our review of the submittal for Tii Gavo Second Addition and have prepared the following comments. Comments crossed out have been addressed and comments in red are in addition to the previous review. The following documents were reviewed: Preliminary Plat - Tii Gavo Second Addition, dated June 13, 2022. Stormwater Drainage Report, dated June 1, 2022 Preliminary Civil Plan Set – Tii Gavo Second Addition, dated June 1, 2022. Final Plat - Tii Gavo Second Addition, dated September 20, 2022. Stormwater Drainage Report, dated September 21, 2022 Civil Plan Set – Tii Gavo Second Addition, dated September 21, 2022. Grading, Drainage and ESC Plans 1. The project is located within Carnelian-Marine-St. Croix Watershed District. Indicate in the drainage narrative how the rules and requirements of the watershed are being met. Plans shall be submitted to the watershed district for review and approval. a. Verify correct wetland buffer limits. Private driveway may be encroaching wetland buffer on northeast portion of the site. 2. Adjust drainage and utility easement to include buffer area 4 as noted on sheet C1.4 on construction plan set. 3. Confirm that Watershed District does not have additional floodplain modeling and/or critical flood elevations defined in the area that may dictate creation of compensatory flood plain excavation to mitigate filling within the floodplain. 4. Provide summary table in Drainage Narrative comparing 2-year, 10-year, and 100-year rainfall event. The table shall include the following: a. Existing and proposed discharge rates into existing wetland areas. b. Existing and proposed peak water surface elevations in wetland areas. 5. All low openings shall be a minimum of 2’ higher than the 100-year high water level. 14727 209 t h St. N. PO Box 128, Scandia , Minnesota 55073 Phone (651) 433 -2274 Fax (651 ) 433 -5112 h t t p://www.ci .sc andia.mn.us 6. Update the SWPPP information to make sure the current Construction Stormwater General Permit requirements (MNR100001) in Section 5 have been satisfied. 7. The SWPPP quantity table needs to be filled out. 8. Provide construction details for proposed pond outlet control structures and filtration areas 9. All emergency overflow elevations shall be noted. 10. Plans shall include both plan and profile views of the storm sewer and street. 11. Lots shall be graded to drain to adjacent drainage and utility easements. Drainage shall not flow directly to adjacent lot. For example, Lot 3, Block 1 shall not drain directly onto Lot 4. Review for each lot. Sanitary Sewer & Water 12. Include existing sanitary sewer in plan set, including valves, curb stops, clean outs, etc. 13. The plans shall include both plan and profile views for the sanitary sewer to verify any potential conflicts with grading and storm sewer. 14. Condition of crossing pipes shall be verified prior to street construction. 15. Each lot shall indicate the sewer station, curb box elevation, sewer service invert elevation at the property line, and riser elevation information. 16. Show any existing wells on the plans. 17. All sanitary and water shall be privately owned and maintained. Street Improvements 18. The proposed pavement width of Meadowridge Trl N shall be 24 ft with 2 ft shoulders. 19. The bituminous pavement thickness shall be revised to provide 4” of pavement, see comments on typical section. 20. The street plans shall include both plan and profile views. General Comments 21. Well system will be permitted by the Minnesota Department of Health. 22. After final restoration and turf establishment reaches 70% coverage applicant shall request final inspection through the City of Scandia. 23. The plans shall clearly identify removals necessary, specifically at the exiting road connection at each end. Full depth and full street width saw cut required at each connection. 24. The specification for construction shall be submitted for review with final plans. 25. Site improvements shall be coordinated with the private utility owners. Conduit crossings for private utilities shall be shown on the construction plans. 26. A preconstruction meeting is required to be held prior to any construction activity starting on site. The developer shall invite representatives from the City, Watershed and the private utility owners. 14727 209 t h St. N. PO Box 128, Scandia , Minnesota 55073 Phone (651) 433 -2274 Fax (651 ) 433 -5112 h t t p://www.ci .sc andia.mn.us 27. Revised documents shall be submitted for review and acceptance prior to any construction activity starting. 28. Please respond in writing as to how the above comments will be addressed. 29. Vertical curves between STA 20+86 and STA 23+57 do not provide sufficient stopping sight distance. See comment on plan set on page C1.5. 30. Ensure water in sand section drains into ditch/storm sewer at low points, either by drain tile or daylight sand section. 31. Provide verification from the watershed district that individual lot treatment is required as homes develop throughout the site. 32. Existing total drainage area = 28.8 acres, Proposed total drainage area = 28.0 acres. Verify if these areas should be the same or justify the difference. 33. Table 4 – Offsite Southeast indicates an increase in discharge rate for the 2-year, 10-year and 100-year event. 34. Rate control and water quality must be met for the entire subdivision per CMSCWD review. This includes accounting for full buildout impervious areas. Each lot will be reviewed prior to construction for volume control. 35. Make sure all EOF’s are identified. Please do not hesitate to contact me at 612-597-7140 with any questions or comments you may have regarding this memo. Sincerely, Ryan J. Goodman, P.E. City Engineer