Letter from Riley-Purgatory-Bluff Creek Watershed District 4-1-09
Riley
Purgatory
Bluff Creek
Watershed District
Board of Managers
Jee Discl.off
Michael Casanova
Howard Peterson
Kristine Sundberg
Kenneth Wend
_.r1leywd.org
April 1, 2009
RECEIVED
MAY 1 3 2009
cnvOF CHANHASSEN
Robert Generous, Senior Planner
City of Chanhassen
7700 Market Boulevard
Chanhassen, MN 55317
Subject:
Chanhassen Public Works Facility
Planning Case 08-25
Dear Mr. Generous:
The Board of Managers of the Riley-Purgatory-Bluff Creek Watershed District has reviewed
the additional plans and your response to our letter dated February 9th regarding the
Chanhassen Public Works Facility. We appreciate your detailed response.
The information you provided indicates that all of the runoff from the site will eventually
flow to the existing stormwater pond southeast of the site. This stormwater pond then
discharges to Riley Creek. While it appears that the additional chloride loading to
Riley Creek would be minimal, we encourage the city to implement good housekeeping
practices to mitigate any unnecessary chloride loading to Riley Creek.
We also request that the City assure that any fuel spills will be properly mitigated. Given
that Riley Creek is impaired for turbidity, please provide your calculations that show that
the water quality volume treated by the existing pond is one inch of runoff from the new
impervious surfaces created by the project.
We are aware that the City requested and granted variances for this project. Our
understandirtg of the variances indicate that they are not justifiable. Setbacks are provided
to buffer sensitive resources from the impacts of increased impervious areas. The setbacks
currently in the City ordinance are the minimum that are considered protective of these
resources by numerous jurisdictions nationwide.
If you have any questions, please contact me at 651-365-8542.
Sincerely,
CH2M HILL
Engineers for the District
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Mark B. Enochs
Vice President, Program Manager
Engineer - CH2M HILL, 1295 Northland Drive, Suite 200, Mendota Heights, MN 55120 tel 651 688-8100
Coordinator- Krebsbach and Haik, 100 South Fifth Street, 19th Floor, Minneapolis, MN 55402 tel 612 333-7400
,
Approved by the Board of Managers
RILEY PURGATORY BLUFF CREEK WATERSHED DISTRICT
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c: Board of Managers