HomeMy WebLinkAboutResponse to Comments about grading and stormwater plan t
ANDERSON ENGINEERING of Minnesota,LLC
CIVIL ENGINEERING & LAND SURVEYING
13605 1st Avenue North,Suite 100 • Plymouth, Minnesota 55441 • Tel:763.412.4000 • Fax: 763.412.4090
June 18, 2009
Ms. Melanie Curtis Via Email: mcurtis@ci.orono.mn.us
Planning &Zoning Coordinator
City of Orono
P.O. Box 66
Crystal Bay, MN 55323
RE: 2687 Wayzata Boulevard —Response to Comments
Orono Building—Spensa:Development
AELLC Project 11586
Dear Ms. Curtis:
We are writing in response to the comments provided by Darren Amundsen of Bonestroo for the grading
and stormwater management plan dated May 19, 2009 for parking lot expansion and rain garden at 2687
Wayzata Boulevard. Responses by Anderson Engineering (AE) directly follow each comment.
Bonestroo: Concrete curb and gutter should be installed around the perimeter of the
parking lot.
AE: Per June 8th on-site meeting, it was concluded that this is a private parking area and surface
water sheet drains to rain garden; therefore, no curb is necessary.
Bonestroo: The discharge rates for the rain garden (4.63 Cris 10-year and 6.79 cfs 100-
year event) exceed those of the existing conditions(2.96 cfs 10-year and 4.50 cfs 100-
year event). All runoff rates for proposed conditions should be less than or equal to
existing condition rates.
AE: Rain garden area/size has been adjusted and post run-off rates are less than or equal to pre run-
off rates. Revised summary stormwater report.
Bonestroo: Geotechnical reports for the adjacent Crystal Bay Business Center indicated
that parking lot pavement sections include a 12-inch select granular,6-inch aggregate
base,and 3-inch bituminous pavement section for normal duty pavement. Heavy duty
pavement(drive lanes of the parking lot) was to have 24-inches select granular,8-inches
of aggregate base,and 4-inches of bituminous. We would recommend using these
pavement sections or have the applicant submit a geotechnical report stating that the 6-
inch aggregate base and 2.5-inch bituminous is sufficient.
AE: Private parking areas maintain X section and private drive aisle was increased to 3% "
pavement section per on site discussion with Tom Kellogg.
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Response to Comments June 18,2009
Bonestroo: Draintile should be provided for the rain garden.
AE: Updated plans and details to reflect 6"draintile in rain garden.
Bonestroo: The applicable code section is 79-7(c)(2)for all commercial or industrial sites
in which land disturbance activities fill or excavate more than 100 cubic yards.
AE.- Plans and narratives were revised to meet code.
Sonestroo: To bring this submittal in to compliance with the ordinance,the following
information should be provided separately or on the grading plan.
Phasing plan. A phasing plan shall be provided that clearly indicates the areas in
the order they are to be disturbed and restored.The phasing plan shall consider
minimization of area and duration of exposed soil and unstable conditions,
minimization of the disturbance of natural soil cover and vegetation,erosion and
sediment control measure installation,weather conditions and the schedule for
temporary and permanent restoration.The area and duration of each phase shall
be indicated on the plan.
AE: Phasing plan sequencing has been added to the grading plan.
Standard detail sheet. A standard detail sheet shall be provided that consists of
applicable construction details for approved erosion and sediment control
measures as developed by the City. Other techniques may be used upon prior
approval by the City with details provided by the designer.
AE: Standard details are shown on Grading/Site Plan and Erosion Control Plan.
Specifications. Written specifications for land disturbance activities such as
product descriptions, installation and maintenance procedures required by the
applicant to carry out the project in accordance with this Chapter.
AE: Written narrative is provided on Grading Plan via SWPPP Notes and Procedures.
Temporary erosion and sediment control plan: Indicate the location of perimeter
controls,construction fence,temporary sedimentation basins, inlet protection,
areas to be seeded,areas to be mulched or blanketed, location of construction
waste control (dumpsters,chemical storage,concrete washout, portable restroom
facilities, etc.)and all other required temporary erosion and sediment control
measures. This plan shall also indicate staging of temporary erosion control
measures.
AE.- Added Temporary Erosion Control Plan. Narrative and notes dictate appropriate
sequencing and staging for temporary erosion measures.
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Response to Comments June 18,2009
Permanent erosion and sediment control plan: Indicates areas to be seeded and
sodded, sediment ponds,storm sewer systems and all other required permanent
erosion and sediment control measures. Permanent storm water pollution
controls including, but not limited to ponds,vegetated buffers and structural
measures shall be designed and constructed in accordance with other Chapters of
the City Code and requirements of other agencies having jurisdiction.
AE:Added Permanent Permit Erosion Control Plan. Narrative and notes dictate appropriate
sequencing and staging for permanent erosion measures.
Narrative: Describes,at a minimum,the nature of construction activity, person(s)
responsible for inspection and maintenance of site erosion and sediment control
including contact information, project phasing,schedules,along with the timing,
installation and maintenance of erosion and sediment control measures and
specifications necessary to carry out the project.
AE: Narrative added on Grading and Phasing Plan.
The$2,000 financial guarantee identified in Section 79-7(b)(2) should be
sufficient for this project.
AE: Owner to provide.
Please feel free contact me with any questions. My direct dial is 763.412.4017 or
mbrandvold@ae-mn.com.
Sincerely,
Anderson Engineering of Minnesota, LLC
Michael B. Brandvold, P.E.
Enclosure:
c Roger Anderson, Anderson Engineering of MN, LLC
Greg Engel, Spensa Development
Darren Amundsen, PE, Bonestroo
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