HomeMy WebLinkAbout2002-11-01 PW Memo Re Brown's Creek Permit ViolationsCity of
Oak Park Heights F � E C U P Y
I
14168 Oak Park Blvd Me Box 2007 ■ Oak Park Hei NIN 55082 * (651) 439-4439 0 Fax 439• 0574
Interoffice Memo
To: Ma and Cit Council
From: Public Works Director, Ja Johnson, PE
CC: Cit Administrator, Cit En Communit Development Director, BCWD
En and Administrator
Date: 11/01/02
Re: Browns Creek Meetin on Centur Power Permit Violations
Centur Power: Centur Power had made sufficient effort in fixin their erosion controls
that the BCWD Board did not find them in violation. The BCWD Board took no actions.
Staff will be takin further actions at Centur Power to brin their erosion control efforts
into as full compliance as feasible and to prevent a catastrophic failure this sprin
Centur Power's contractor had stated that the modified the g radin g and chan the
location of the silt and tree protection fences were made to save oak trees. A review of the
area indicates that the chan ma have resulted in loss of more trees than were saved.
These field chan have also resulted in the slope bein much steeper than desi
With these slopes mechanical e would have difficult in removin the sediment
from the fences. The need to g et the slopes stabilized prior to frost so we do not loose the
hill into the woods with sprin run-off.
TREE CITY U.S.A.
Their erosion control plan that was
approved as part of their building plans
required the removal of sediment from
the fence wherever the sediment
reaches Y2 of the height of the fence.
Their Browns creek permit requires
removal at 1 /3 of the height. Instead of
removal they installed additional fences
in front or closely behind the fence that
was failing. In one spot they have four
fences forming a weak retaining wall.
Two of the fences have been
overtopped by sediment. If the
sediment is allowed to fill in more than
0 inches in the current fence, the
weight of all this material on the lower
fences may cause a failure of all four
fences and release the stored sediment
into the woods.
Staff has written a letter informing there that they are not within full compliance with their
building plans and what steps they need to take to come into compliance. The following
steps well be reviewed with our City Engineer, Building official and the BCWD Engineer:
The following erosion control measures are the minimum required for the temporary
erosion control plan and are to be implemented immediately on the site.
1. Sediment deposits on the new fences must be removed when they reach six inches
deep. As an alternative, the conditions of the original erosion control plan could be
complied with and the sediment removed from all of the fences followed by the repair
and replacement all of the original sedimentation fences. If the sediment removal and
repair option is chosen these repairs must be completed by November 7, 2002.
2. The erosion control fences installed part way up the hill must have the flap buried a
minimum of six inches below the ground and the soil firmly packed around the flap by
November 7, 2002.
3. Erosion control inspections shall be performed and documented with a written record
at least weekly until frost is well established in the ground and after every rainstorm. In
the spring an inspection shall be made and documented prior to the spring melt and no
later than March 1, 2003. weekly inspection and inspections after each rainstorm will
be made and documented after March 1, 2003 and until final slope stabilization has
been completed with permanent vegetative cover.
4. To prevent erosion during spring run off, the slopes need to be stabilized prior to frost.
At a minimum all slopes over 5:1 will be:
2
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TREE CITY U.S.A.
a. Topped with black dirt as specified in the landscaping plan. If bulldozers or other
equipment is used to spread the dirt, the final passes of the equipment should be
such that the track or tire marks do not form channels that point down the hillside.
With a tracked vehicle, the final pass should be up the hillside leaving a series of
cleat marks perpendicular to the slope and will work as hundreds of small check
dams rather than hundreds of small erosion channels.
b. seed the with a grass seed mixture for side slopes and woodland transitions that
have limited sun. The seed mixture should be specified by a landscape architect
that is practiced in erosion control and native plant restoration. The MNDOT 5A
Modified or 5B is listed in the M N DoT spec book for woodland transition with up to
50% shade.
c. Install and securely stake down erosion blanket material that will help minimize
erosion in the spring.
d. Areas with slopes less than 5 :1 will be planted and stabilized in accordance with
the approved landscape plan.
If you have any question, please contact me.
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TREE CITY U.S.A.