HomeMy WebLinkAbout6.g. SKB Interim Use Permit Amendment for the End Cap DesignCITY OF ROSEMOUNT
EXECUTIVE SUMMARY FOR ACTION
City Council Meeting Date: November 3, 2004.
AGENDA ITEM: SKB Interim Use Permit Minor
AGENDA SECTION:
Amendment.
Consent.
PREPARED BY: Rick Pearson, City Planner.
AGE% . #6 G
ATTACHMENTS: Proposed Exhibit E (drawing and design
info) , March 6, 2003 City Council
APPROVED BY:
minutes
RECOMMENDED ACTION:
Motion to amend the SKB Interim Use Permit Section 98 to approve a revised Exhibit E
depicting a closure plan that has a sloped gradient and planted with grasses.
ACTION:
ISSUE
The application before the Council is to modify the design of the end -cap at the SKB land -fill
The change is to provide a gradual slope with grasses versus a previous plan that had ridges
with landscaping to recreate an oak savannah. The previous idea depended on a significant
amount of soil being added to the site to provide a sufficient depth for tree roots that would
not puncture the end cap liner. The simplified strategy of a uniform 2.5 ft. thick soil layer with
6 inches of top soil, seed and liner will be much easier to maintain, and greatly simplifies
repairs to the end cap if necessary.
BACKGROUND
On March 6, 2003, the Council approved a major amendment to the SKB Interim Use Permit
with conditions. The effect of the major amendment was to increase storage capacity by
utilizing "saddle" area between cells. The major amendment also approved a new
construction demolition cell along the southeast elevation of the land -fill.
One of the issues discussed by the Council, and noted for further discussion and refinement,
was the end use plan for the site. The, plan at that time included groupings of trees on ridges
that advanced up the slope, allowing for sufficient depth to protect the liners of the end cap
from roots. The exact details of the landscape project were not worked out when the IUP
was approved. After further examination it became clear that the project entailed more
resources than initially expected. For this reason, the city and SKB have been looking at
other options that would address previous city concerns. The present concept will allow a
more sloped mound that will be easier to maintain. Further, the introduction of trees on the
site required a significant amount of fill and dramatically increased the cost. The reason is
that a lot of soil was needed to ensure that the end cap was punctured by the tree roots.
Applicant & Property Owner(s):
Location:
Area in Acres:
Comp. Guide Plan Desig:
Current Zoning:
City Council Action:
John Domke for SKB Environmental
TH 55 Industrial Waste Containment Facility
Approx. 235 acres
Waste Management
Waste Management
Approved with conditions 3 -6 -2003.
SUMMARY
There is the potential for the City to have to become involved with repairs after the cells have
been closed. While the tree planting plan can certainly be engineered properly, the cost of
maintenance and repairs could be unusually high, particularly on the 4:1 side slopes. Staff is
comfortable with the various aspects of the revised proposal; uniform gradients, depth of
cover, and turf management. Reasonable visual screening can be accommodated with tree
plantings near the highway right -of -way. The changes in the IUP will also be reflected in the
SKB Community Trust Management Plan.
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3.6.4 Storage Tanks
Three leachate storage tanks are located near the access road to the west of Cell 1. The tank
design includes a secondary containment structure which is a concrete, bermed pad capable of
containing the capacity of one of the tanks plus the 25 -year, 24 -hour storm event and freeboard.
See Drawing No. 30. Each tank has a capacity of approximately 250,000 gallons and has a leak
detection system. The design will provide flexibility to accommodate the total leachate
generated under extreme precipitation conditions and the discharge volumes allowed by the city
of Rosemount and the MCES. The tank surfaces are and will be coated or painted to prevent
corrosion. Currently one of the tanks is insulated to prevent freezing. The remaining tanks will
be insulated as needed.
--�- 3.7 Final Cover
3.7.1 Design
Closure of each subcell will be initiated when that subcell reaches final capacity. It is anticipated
that this will occur about once every three to five years over the estimated 25 -year life of the
Facility. The Cell Closure Plan, as identified in Section 8, will be applied to each subcell. As
the closure and post closure care operating experience dictates, adjustment and amendments may
be made to future subcell closure designs and activities.
The entire Facility, Cells 1 through 5, will have the same final cover constructed. See Drawing
No. 25 for the final cover typical details. A typical cross section of the completed final cover
consists of the following:
A prepared waste mound,
• A layer of unclassified compacted soil (free of sharp rocks or debris that could potentially
damage the liner) 1 -foot thick,
• 40 -mil Linear -Low Density Polyethylene (LLDPE) liner,
A geocomposite drainage net,
• A soil layer 2.5 feet thick, and
A 6 -inch layer of topsoil and vegetative cover.
The sequence to close a cell /subcell will begin with preparing a waste mound beginning at the
perimeter of the cell - subcell and working inward. The mounding of the waste will reduce the
subsequent need for additional earth fill material, facilitate grading of the soil cap and reduce the
possible formation of depressions that could pond water.
The 1 -foot soil layer will be placed and compacted over the waste surface of the final cover
sub grade, progressively, so that run off is contained within the cell /subcell confines.
KLL1 \KAo1 Sol 9 \Report\R -Vol 1 PermitApplication \10000 Major Modification Foth & Van Dyke • 13
October 2001
Following a settlement and observation period, additional subgrade soil; if needed, will be placed
and compacted to correct the surface from the effects of any settlement or subsidence. The 40-
mil LLDPE liner will then be installed. A geocomposite drainage net (i.e. drainage net with
geotextile filter fabric on one or both sides) will be placed atop the LLDPE liner.
A layer of soil 2.5 feet thick will be placed over the drainage layer and will be contoured to avoid
forming any depressions that might pond water.
A 6 -inch layer of topsoil will be placed over the 2.5 feet of soil cover and seeded, mulched and
fertilized to promote the vegetative cover.
3.7.2 Seed Mix
The seed mix will be based on approved mixes at the time of closure. Intermediate soil layers
will be seeded with typical shallow- rooted, drought - resistant, grasses.
The Overall Site Contour Plan may use a native seed mix along with trees and shrubs.
Foth & Van Dyke • 14 KLL1 \KA01S019 \Report \R -Vo11 PermitApplication \10000 Major Modification
October 2001
Excerpt from the Regular City Council Meeting of March 6, 2003
SKB Interim Use Permit Modification
Community Development Director Parsons reviewed discussion for the Interim Use
Permit (LU.P.) that would call for renewal every five years. The Permit is tied to state
and county approval. The Rosemount Community Trust Fund will be required to be
updated within a year from approval of the I.U.P. The end use of the property will affect
each cell as it is filled and closed. Hazardous waste will not be accepted at any time as
waste material. The MPCA will maintain records of waste material. Council requested
that they receive all reports issued from and to SKB Environmental, Inc. The MPCA did
decide to have an Environmental Assessment Worksheet done for this expansion. SKB
had prepared this worksheet prior to the MPCA's request so time was saved. MPCA
noted that on the first review of that document there were no "red flags" or concerns. A
public notice will go out for 30 days before a public hearing to allow residents to
respond. Beth Lockwood, Supervisor for EPA, noted that notice will be mailed as well to
interested parties. A response will be made to each person who contacts the MPCA,
which will take a few weeks. So it will likely be two months before approval is complete.
Rick O'Gara, President of SKB Environmental, Inc. said they would like to begin
construction in the spring. The City's intent for approval of the Interim Use Permit needs
to be sent along to the MPCA and Dakota County for them to begin their process of
approval. O'Gara noted that traffic has been improved by routing trucks to County Road
38 during peak traffic times on Highway 52.
Staff was directed to tighten language in a few places of the permit. Council noted that
the end use could possibly change in the future and that. the closure cost should be
adjusted to current values by adding "in 2003 dollars ". O'Gara noted that any change in
the end use plan would have to have the approval of the MPCA and Dakota County.
MOTION by Riley to authorize execution of an amendment to the I.U.P. to SKB
Environmental, Inc. conditional on City receipt and approval of EAW and SKB would be
responsible to copy any reports to the City. City Attorney LeFevere noted he had
composed a motion more inclusive. Council Member Riley withdrew her motion and
moved LeFevere's motion.
MOTION by Riley to approve the Interim Use Permit and approve the execution of the
proposed Interim Use Permit and Development Commitment with the following changes
to the Interim Use Permit Agreement: 1) add that all inspection reports received by SKB
from the MPCA, Dakota County, OSHA and other governmental regulatory agencies
shall be forwarded by SKB to the City within five working days of receipt, 2) add that
reports submitted by SKB to the MPCA, Dakota County, or other governmental
regulatory agencies shall be submitted to the City simultaneously, and 3) add that
references to the cost of the approved post closure plan be changed to reflect that they are
stated in 2003 dollars; provided, however, that such approvals are effective on May 16,
2003. The City Council may delay such effective day and approval may be reinstated
following completion of the environmental review process conducted pursuant to
Minnesota Statutes, Chapter 176D. Second by Shoe - Corrigan. Ayes: Strayton,
DeBettignies, Shoe - Corrigan, Droste, Riley. Nays: None. Motion carried.