ITEM 3.1_attachmentReview No. 1
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ENGINEERING REVIEW
Residential Subdivision
for the City of Otsego
by
Hakanson Anderson
Submitted to: Honorable Mayor and City Council
cc: Adam Flaherty, City Administrator
Tami Loff, City Clerk
Dan Licht, City Planner
Andy MacArthur, City Attorney
Tony Bolduc
Jeffery Prasch, The Gregory Group, Inc.
Reviewed by: Ronald J. Wagner,
Brent M. Larson
Date: September 27, 2017
Proposed
Development: Raspberry Hills
Street Location A portion of the NE'/4 of the SW'/4 of Section 21, T121, R23.
Of Property: West of Odean Avenue NE and South of 85th Street NE.
Applicant: Tony Bolduc
Developer: 15099 Scenic Drive
Dayton, MN 55327
Owners of Record: Jeremy & Cherlynn Uzzell
8465 O'Dean Avenue NE
Otsego, MN 55330
Purpose: Raspberry Hills is a proposed 10 single-family low density
residential lot development on approximately 15 acres in the City
of Otsego, Wright County, Minnesota. The proposed development
unsewered one plus acres. The proposed development will be
served with municipal storm sewer and public streets typical of an
urban setting.
Jurisdictional Agencies: City of Otsego, Wright County, Minnesota Department of
(but not limited to) Health, Minnesota Department of Natural Resources, Minnesota
Pollution Control Agency, Wright Soil and Water Conservation
District.
Permits Required: NPDES, Minnesota Department of Health (water),
(but not limited to) Minnesota Pollution Control Agency (sanitary sewer), and Wright
County
TABLE OF CONTENTS
INFORMATION AVAILABLE
PRELIMINARY PLAT
FINAL PLAT
CONSTRUCTION PLANS
TITLE SHEET
DETAILS & CONSTRUCTION NOTES
DETAIL AND SWPPP NOTES
SWPPP
EXISTING TOPOGRAPHY AND REMOVALS
GRADING PLAN AND LOT TABULATION
TREE PRESERVATION PLAN
UTILITY PLAN
STREET AND STORM SEWER PLAN AND PROFILE
STORM SEWER DESIGN/HYDROLOGY
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OTHER CONSIDERATIONS
SUMMARY AND/OR RECOMMENDATION
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INFORMATION AVAILABLE
Site Development Plans for Raspberry Hills, dated 9/5/17, by The Gregory Group, Inc.
Final Plat for Raspberry Hills, by The Gregory Group, Inc.
Preliminary Plat for Raspberry Hills, dated 8/2/17, by The Gregory Group, Inc.
Storm Water Management for Raspberry Hills, dated 9/5/17, by The Gregory Group, Inc.
Soils Logs for Individual Sewage Treatment Systems, dated 8/31/17 by Halling Engineering, Inc.
Wetland Determination Report, dated 9/20/17, by Kjolhaug Environmental Services Company,
Inc.
Additional Information
Minnesota Rules, Chapter 4410 — EAW Requirement
City of Otsego Engineering Manual
City of Otsego Zoning and Subdivision Ordinances
National Wetland Inventory Map
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PRELIMINARY PLAT
1. The preliminary plats are required to show the following information;
a. Show location, names, widths of existing streets, buildings, etc within 150'.
b. Location, size, and elevations of existing sewers, watermain, culverts, and other
underground facilities within 150'.
c. Boundary lines of adjoining unsubdivided or subdivided land, identified by name and
ownership within 150'.
d. 100 -year flood elevations.
e. The proposed well locations shall be shown.
f. The proposed house (garage floor, lowest opening, and basement) elevations shall be
shown.
g. Provide proposed width of lots at setback line when on a curve.
h. Provide proposed centerline lengths, horizontal curve information, centerline gradients,
roadway widths, and typical cross-sections are needed.
2. Much of the storm sewer layout and storm sewer ponding does not match the final design
shown in the construction plans.
FINAL PLAT
3. 50' of right-of-way was previously obtained along 85th Street and Odean Avenue by the
City. Additional permanent easement along these streets was also obtained beyond the
right-of-way and varied from 16.5' wide to 33' wide.
4. The storm water basins shall be within platted Outlots which shall be deeded to the City.
5. Separate documentation providing ingress/egress easements are required for access to
Lots 2 and 4, Block 1.
6. The culvert under Lot 4's driveway is critical to Lot 3 draining. The drainage and culvert
should be covered by an easement.
CONSTRUCTION PLANS
Title Sheet
7. Provide an approval signature line for Ronald J. Wagner, P.E. City Engineer.
Details and Construction Notes
8. Detail NO shall callout a casting/grate
9. A geotechnical report is required with a recommended "R" value and the appropriate
streets section shall be called out in detail 4/C3
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Details and SWPPP Notes
10. Overlapping text in existing pond located at SE comer of 80th Street and Maciver
Avenue.
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11. No comments.
Existing Topography and Removals
12. See preliminary plat comments for additional existing conditions requirements.
Grading Plan and Lot Tabulation
13. All cross drainage shall be directed along lot lines or contained within drainage easement.
The following locations shall have the grading revised or easement platted:
a. The cross drainage through the rear of Lot 2
b. From the side of Lot 3 through Lot 4 to the culvert.
c. The cross drainage from the side lot line between Lots 6 & 7 through Lot 6's
septic areas.
d. The cross drainage from the side lot line between Lots 5 & 10 through Lot 5's
rear yard.
14. A maximum slope of 4:1 is allowed. It appears a few areas have 3:1 slopes. Please label
all slopes 4:1 or steeper.
15. The NWL, 2 -yr, 10 -yr, 100 -yr high water levels shall be labeled for the ponds.
16. Verify the slope across the septic area of Lot 10, a maximum slope is 12% or 18% for a
trench system.
17. Label the top of berm elevation between the forebay and the infiltration area in Pond 4.
If this is an earthen berm it should be protected from washing out (cable concrete or
possibly use a rock filter instead). We have had issues with similar ponds where the
berm has washed out when this close to and directly across from the discharge point.
18. The pond inlet (FES 214) is too close to the outlet (FES 100) which will cause short
circuiting of "Pond 6". Would it be possible to connect the pond inlet pipe directly to the
outlet pipe and bypass/eliminate the pond as the downstream regional pond already
accounts for this site runoff.
19. The low area west Oday Court (near the CB's) needs to be filled (beyond the property
boundary) or a pipe needs to be extended to pick up the water being trapped here.
Tree Preservation Plan
20. No comments.
Utility
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21. No comments.
Street and Storm Sewer Plan and Profile
22. Provide the storm sewer pipe and structure information (sizes, elevations, slopes, etc.) in
the profiles.
23. Label the structures in the plan view.
24. The maximum horizontal grade difference is I% without a vertical curve. Verify the
grade difference near station 0+50 along 83rd Street does not exceed 1 %.
25. Show the storm sewer structure at 2+39 along Oday Court in the profile.
STORM SEWER DESIGN/HYDROLOGY
26. The storm water runoff for this site has been accounted for in the downstream regional
pond in the NW quadrant of 85th Street and Odean Avenue. Only the infiltration
requirements (1.1" runoff from all new impervious surfaces) need to be met onsite.
27. The storm water report states the in-situ soils determined to be Hydraulic Soils Group A
in the location of the infiltration basins. The soils map indicates soils to be 740 (Hamel
loam, Hydraulic Group C) and 106D2 (Lester loam, Hydraulic Group Q. Justification
for using Group A infiltration rates is necessary. It may be necessary to test infiltration
rates after the basins are constructed to ensure they are functioning as designed.
28. The entire site infiltration requirements are being met in Pond 4. The need for Pond 6 is
unclear. Justification is necessary as to why none of the required infiltration volume is
being utilized in Pond 6.
29. Provide storm sewer pipe sizing calculations using the rational method.
WETLANDS
30. The Wetland Determination Report, dated 9/20/17, has been received and under review.
DEVELOPMENT PLAN
31. A development plans shall be provided with the following requirements;
a. Include a north arrow and bar scale.
b. All setback and easement lines shall be shown.
c. House pads shall be shown (within setback lines).
d. Denote House Type and Garage Floor, Lowest Opening, and Lowest Floor elevations by
Block and Lot. A separate (pdf. word or excel) document must be provided listing house
type, Garage Floor, Lowest Floor, and Lowest opening elevations by Block and Lot.
e. The legend should include abbreviations for house types.
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f. Include drainage arrows (no existing or proposed contours should be shown).
g. Proposed finished grade street centerline elevations and gradients shall be shown.
h. Elevations at lot corners shall be called out.
i. Emergency Overflow (EOF) elevations shall be called out on the plan.
j. Plan shall be certified by the design engineer.
32. A lot tabulation (separate word, excel, or pdf document) must be provided listing
proposed House Type, Garage Floor, Lowest Floor, and Lowest opening elevations by
Block and Lot.
OTHER CONSIDERATIONS
33. A geotechnical report with a recommended "R" value for the street design shall be
submitted.
34. A statement certifying the environmental condition of the site including the presence of
any hazardous substance as defined in Minnesota Statutes 11513.02, Subd 8 is required.
SUMMARY AND/OR RECOMMENDATION
Contingent upon the above items being addressed we recommend Revise and resubmit.
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