HomeMy WebLinkAbout2022-09-16 Stantec Civil Plans & Stormwater Calculations Review Stantec 733 Marquette Avenue Suite 1000,Minneapolis MN 55402-2309
September 16, 2022
File: 193800151
Attention: Mr. Eric Johnson
City of Oak Park Heights
14168 Oak Park Blvd.
Oak Park Height, MN 55082
Reference: St. Croix Car Wash -Civil Plans and Stormwater Calculations Review
Dear Eric:
As requested, we have reviewed the information submitted regarding the proposed St. Croix Car Wash
project. The information reviewed includes engineering plans dated 8-18-2022, and stormwater calculation
documents dated 8-16-2022. Following are our comments and/or recommendations:
Site Development Plan
1. The driveways need to meet the City commercial driveway standards. Include City Detail Plate
STR-8.
2. Label size of sewer and water services. Unless the proposed water service is 2-inches or less, a
wet tap will not be allowed. Further comments may be forthcoming when services sizes are
identified.
3. Connections to the City's sewer, water and storm sewer systems shall be per the City's standards
and detail plates. The City or it's designee shall be present for water and sanitary sewer service
connections to the City's systems, add a note to the plan to this effect.
4. Include City Detail Plate SER-6, PVC Sanitary Service Saddle Connection.
5. Include City Detail Plate WAT-3, Gate Valve and Box Installation.
6. Show limits and detail for street repair at sewer and water connection points. Pavement section
shall match existing.
7. Provide engineered design for the retaining wall.
8. Refer to the Fire Department review of fire lanes and circulation.
September 16,2022
Mr. Eric Johnson
Page 2 of 3
Reference: St. Croix Car Wash—Civil Plans and Stormwater Calculations Review
Grading and Drainage Plan
1. Refer to the stormwater comments below.
2. Include erosion control on grading plan.
3. The storm sewer that serves the site will be private and maintained by the owner.
4. Include detail for connection to existing MH 3.
5. The Owner will need to comply with all related requirements of the NPDES Construction
Stormwater Permit and the Middle St. Croix Watershed Management Organization.
6. Include all applicable City Detail Plates.
7. The City reserves the right to require additional erosion control measures as determined/necessary
during the construction of the project.
Details
1. Include/Utilize City Detail plates where applicable.
Storm Sewer/Storm Water Management
1. Sheet C3 shows a 12" PVC standpipe in the northern raingarden (Raingarden B2). The HydroCAD
model indicates the outlet is a 24" diameter standpipe with a slotted grate. Verify outlet
configuration and update the plans and/or HydroCAD so they match.
2. Sheet C3- Label EOF locations and elevations for each raingarden
3. Sheet C7 - Detail 4- Standpipe outlets should include grate type caps
4. Sheet C7 - Detail 5- Raingardens must be lined below the drain tile with an impermeable liner(e.g.
clay, geosynthetic).
5. HydroCAD indicates that the southern raingarden (Raingarden B1)will outflow through an overflow
spillway during the 10-year and 100-yr storm events. Sheet C3 appears to indicate that the flows
through the spillway will flow into the pavement area and flow north along the curb to the northern
raingarden (Raingarden 62). To capture this in the HydroCAD model, the secondary outlet spillway
for Raingarden B1 should be routed to Raingarden B2.
6. Show the runoff south the retaining wall to follow the existing drainage pattern to the east. The
drainage arrows could be interpreted to show the runoff discharging directly to the property to the
south.
September 16,2022
Mr. Eric Johnson
Page 3 of 3
Reference: St.Croix Car Wash—Civil Plans and Stormwater Calculations Review
General Comments
1. The City reserves the right to inspect the construction of the project. The City or its designee shall
be present for water and sanitary sewer service connections.
2. The Owner will need to comply with all requirements of the NPDES Construction Stormwater
Permit and the Middle St. Croix Watershed Management Organization. The City reserves the right
to require additional erosion control measures as determined/necessary during the construction of
the project.
3. Review of issues related to parking, lighting, landscaping, fire department access or the buildings is
by others.
4. The Owner shall be responsible for obtaining all required permits.
5. Utility construction and improvements in the right-of-way need to conform to the City's Standard
Detail Plates. Include all applicable City detail plates on the plans. The City's details can be
provided upon request.
If you have any questions or require further information, please do not hesitate to contact me.
Regards,
4-31/1
MN,WI,CA
Principal
Phone: 612-712-2085
Lee.Mann@stantec.com
c file
Julie Hultman, Building Official
Andrew Kegley, Director of Public Works
Scott Richards, City Planner
Kevin Sandstrom, City Attorney