Memo from L. Haak 10-7-04
CITY OF
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MEMORANDUM
TO: Josh Metzer, Planning Intern
FROM:
Lori Haak, Water Resources Coordinator
DATE:
October 7, 2004
RE:
Monson Variance (Planning Case 04-33)
Upon review of plans recei ved September 17, 2004, I offer the following
comments and recommendations:
BLUFFS
One area on the property has been identified as bluff (i.e., slope greater than
or equal to 30% and a rise in slope of at least 25 feet above the toe).
Chanhassen City Code requires preservation of the bluff area. In addition, all
structures are required to maintain a 30-foot setback from the bluff and all
grading must occur outside of the bluff impact zone (i.e., the bluff and land
located within 20 feet from the top of a bluff), Two retaining walls with a
combined height of xx feet were installed in the bluff area without a pennit.
The existing retaining walls are in violation of City Code.
The applicant is requesting a variance to place a garage/storage structure
within a bluff. In order for the structure to be constructed, the existing
retaining walls would need to remain in place. Staff is concerned about
erosion and sediment control on-site, as well as overall bluff stability.
GRADING, DRAINAGE AND EROSION CONTROL
Erosion control blanket shall be installed on all slopes greater than or equal to
3: 1. All exposed soil areas shall have temporary erosion protection or
penn anent cover year round, according to the following table of slopes and
time frames:
Time
Type of Slope (maximum time an area can remain unvegetated
when area is not actively bcing worked)
Steeper than 3: 1 7 Days
1O:1t03:1 14 Days
Flatter than 10: 1 21 Days
The City of Chanhassen · II growrng com:T1iJ:llly w:lllclean lakes. lIual:ly
a:ld play
lu
Josh Metzer, Planning Intern
October 7,2004
Page 2 of 2
These areas include any exposed soil areas with a positive slope to a temporary or
permanent drainage ditch or other natural or man made system that discharges to a
surface water.
Permanent native vegetation should be installed on the slopes to minimize the potential for
future slope failure.
RECOMMENDED CONDITIONS OF APPROVAL
1. Erosion control blanket shall be installed on all slopes greater than or equal to 3: 1. All
exposed soil areas shall have temporary erosion protection or permanent cover year
round, according to the following table of slopes and time frames:
Time
Type of Slope (maximum time an area can remain unvegetated
when area is not actively being worked)
Steeper than 3: 1 7 Days
10:1 to 3:1 14 Days
Flatter than 10: 1 21 Days
These areas include any exposed soil areas with a positive slope to a temporary or
permanent drainage ditch or other natural or man made system that discharges to a
surface water.
2. Permanent native vegetation shall be installed on the slopes to minimize the potential for
future slope failure.