HomeMy WebLinkAboutRe: grading/retaining walls May 11, 2007
Liesch Associates, Inc.
15400 13�' Ave. North
Plymouth, MN 55351
Terry R. Johnson
543 Park Lane
Orono, MN 55356
Subject: 543 Park Lane - Slope stability
Dear Mr. Johnson,
I have reviewed the survey dated November 6, 2006, which illustrates the proposed
grading and retaining wall locations. Based upon our discussions I understand that the
City of Orono Staff have expressed concern over the bank stability near the location of a
proposed berm on the south side of the property. This area is directly south of the
proposed driveway.
The slope is at a 3V:1H The existing grades in this area are between 971.8 and 971.4 feet
MSL. The proposed grades around the berm are proposed to be reduced to between
970.0 and 970.4 feet MSL. The proposed berm is to be 0.5 feet to 0.9 feet above the new
grade. Thus, the proposed berm will be constructed by lowering of the grade around the
berm rather than a build up. The berm as proposed is actually slightly below the existing
grade and the overall grade in this area is proposed to be reduced between 2.0 feet and
1.0 feet, approximately. Since the proposed berm is slightly lower than existing grades
and the overall grade is also being lowered in this area the load on the slope will be
reduced. Thus, the net effect will be no change in the stability of the adjacent slope.
Please note that the soil beneath the proposed berm should be properly compacted, if
disturbed. Also, the proposed berm should be seeded and mulched to minimize erosion.
I trust that this information meets your needs.
Sincerely,
LIESCH ASSOCIATES, INC.
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Bruce Rehwaldt, P.E.