9. City Code Amendment: Prohibit Chemical Treatment of Algae in Wetlands.CITY OF 9
CHANHASSEN
690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
(612) 937 -1900 • FAX (612) 937 -5739
MEMORANDUM
TO: Don Ashworth, City Manager
FROM: Jill Sinclair, Environmental Resources Coordinator
DATE: January 6, 1997
SUBJ: Ordinance to Amend Sec. 20, Chemical treatment of wetlands
UPDATE
Action by City Administratof
Endorsed �� A
Modified
Rejected _
Dat — 7
Date Submitted to Commission
Date Submitted to Council
-r3 -q
On Wednesday, December 4, the Planning Commission reviewed and unanimously approved the
ordinance amendment to Chapter 20 pertaining to the chemical treatment of wetlands with
changes in the ordinance highlighted in bold.
SUMMARY
At the request of city staff, the Environmental Commission has developed an ordinance
pertaining to the chemical treatment of wetlands. The request to the Commission stems from
staff experiences with residents who have inquired about city policy concerning algae control in
natural wetlands and storm water ponds. Residents have complained of unpleasant views and
odors from wetlands, both natural and constructed, and have wanted to apply herbicides to kill
the nuisance growth. Several homeowner associations already have stormwater ponds
chemically treated to prevent algae growth. While herbicides may provide a clean appearance to
these ponds, the application is extremely detrimental to the effectiveness of the wetland and adds
additional pollutants into the watershed. Algae are naturally occurring cleansing systems that
reduce the amount of nutrients, minerals and sediment in the water that passes through a wetland.
Elimination of the algae and other aquatic plants in a wetland, destroys the pond's ability to clean
the water. The city has no authority at this time to prevent homeowners from chemically
treating the algae in their ponds, even though it would be in direct conflict with the purpose of
the wetland. There are alternatives to chemical treatment which the city wishes to encourage as a
part of this program.
As a response to the request, the Commission has begun a comprehensive plan, including
regulation and education, to address the issue. One component of the plan was the development
of the ordinance. The other is the creation of an informational brochure which will cover the
Planning Commission
November 25, 1996
Page 2
causes of nuisance algae growth and ways to prevent or manage the growth without the use of
chemicals.
The proposed ordinance specifically prohibits the use of chemicals in any type of wetland,
including utility or storm water ponds, for the control of algae. Other items included in the
proposed ordinance are an attempt to keep the city and public informed about what treatments are
being applied to city wetlands. Presently, no notification for any type of treatment, chemical or
otherwise, is required by city ordinance.
RECOMMENDATION
Staff recommends the City Council adopt the following motion:
"The City Council adopts the amendment to Chapter 20 pertaining to the chemical treatment of
wetlands as shown in Attachment #1."
ATTACHMENT
1. Ordinance amendment
CITY OF CHANHASSEN
CARVER AND HENNEPIN COUNTIES, MINNESOTA
ORDINANCE NO.
AN ORDINANCE AMENDING CHAPTER 20 OF THE
CHANHASSEN CITY CODE
The City Council of the City of Chanhassen ordains:
Section 1. Section 20 -407, Wetland alteration, is hereby amended by adding the following:
(b) Chemical treatment of wetlands.
(1) The use of algae controlling chemicals in any storm water ponds or wetlands
is prohibited.
(2) The city must be notified prior to the use of any form of algae control
treatment.
(3) At the time of notification, a person or company will be required to supply
the following information:
a. Location of pond
b. Area of pond to be treated
C. Name, address and telephone number of the party responsible for
treatment
d. Name, address and telephone number of person or persons
performing the treatment.
e. Date of treatment.
f. A list of the type of treatments to be used at said time.
g. A statement indicating an understanding of the treatment being
applied and its effect on humans, plants and wildlife.
(4) One time public notification in the city newspaper is required two weeks
prior to treatment.
Section 2. This ordinance shall be effective immediately upon its passage and
publication.
PASSED AND ADOPTED this day of . 1996, by the City
Council of the City of Chanhassen.
ATTEST:
Don Ashworth, Clerk/Manager
Donald J. Chmiel, Mayor
(Published in the Chanhassen Villager on )