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Plat\Tanager Creek_PrePlatReview_2022-02-09.docx
February 9, 2022
City of Orono
Attn: Laura Oakden
2750 Kelley Parkway
Orono, MN 55356
RE: Preliminary Plat Application
Tanager Creek
Engineering Review #1
Dear Laura:
As requested, I have completed an engineering review of the documents submitted for the above
referenced project. We offer the following observations, comments, and recommendations for your
consideration:
1. One filtration basin is proposed for stormwater runoff management to meet regulatory
requirements. The following must be considered regarding stormwater management:
a. Per MCWD requirements, the proposed stormwater management system must limit
proposed peak runoff rates to that of existing for the 1, 10, and 100 year – 24h hour events.
Per NPDES requirements, the system must also treat the water quality volume, calculated
as 1” times the sum of new and fully reconstructed impervious surface. If infiltration is
prohibited as outlined by NPDES requirements, a wet sedimentation basin or filtration
basin may be utilized.
b. Per City requirements to track TMDLs and reduce loads to meet required Waste Load
Allocations, the calculations for Total Suspended Solids (TSS) and Total Phosphorus (TP)
loading must be provided.
c. Facilities necessary for the ultimate development (street construction, sewer, basins, etc.)
must be installed and the site mass-graded at the same time as street construction to ensure
all drainage ways, watersheds, and runoff management systems are constructed per the
approved Stormwater Management Plan and are sized adequately for proposed
improvements.
d. An 8’ wide bench must be provided around the basin to provide access to the outlet and for
basin maintenance.
e. Basin must be permanently vegetated prior to issuance of any building permits.
f. Native vegetation should be utilized in basins and wetland buffers.
2. Final Plans must include the following:
a. Grading, Drainage, and Erosion Control Plan
b. Street Construction Plan
c. Utility Plan
d. Landscape and Restoration Plan
e. SWPPP meeting NPDES requirements
f. City Standard Details
Preliminary Plat Application
Tanager Creek
Page 2
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Plat\Tanager Creek_PrePlatReview_2022-02-09.docx
3. The applicant will be required to obtain the following permits and provide a copy of any
approvals required prior to Final Plat approval:
a. Sanitary Sewer Extension Permit
b. Hennepin County Access Permit
c. Minnehaha Creek Watershed District (MCWD)
d. NPDES General Construction Permit
4. The private street should be operated and maintained per the City’s standard agreement.
5. The required cul-de-sac radius is 40 ft for pavement and 50 ft for ROW. The proposed cul-de-
sac indicates a radius 45 ft, and 50 ft for the ROW.
6. The addition of three additional services should not exceed the capacity of the adjacent
forcemain. However, the Brown Road forcemain should be reviewed further to ensure the
capacity is adequate and the system does not require additional improvements.
7. The Final utility plan will need to show the curb stops for the forcemain stubs, a terminal
flushing connection at the end of the forcemain, and a profile for improvements indicated.
8. The applicant will be required to submit a Maintenance Agreement for all stormwater
management structures and facilities. The agreement must define maintenance responsibilities
following completion of project, specify types and frequencies of inspection and maintenance
activities, designate who will conduct inspection and maintenance activities, and outline
reporting requirements. The Agreement will be recorded with the County per the City’s
approval process.
9. Drainage and Utility Easements must be provided as follows:
a. Over all sanitary forcemain.
b. Over all stormwater management facilities used to meet regulatory requirements, including
access routes.
c. Over all wetlands, creeks, and buffers.
d. All swales, structures, and piping providing drainage for multiple properties.
e. 5’ along all side lot lines, unless adjacent to Development boundary.
f. 10’ along all front lot lines, rear lot lines, and adjacent to Development boundary.
If you have any questions or comments, please contact me to discuss.
Sincerely,
Bolton & Menk, Inc.
Robert E. Bean, Jr., P.E.
Water Resources Engineer
CC: Adam Edwards, Director of Public Works / City Engineer