1c. Riley-Purgatory-Bluff Creek Request for Variance on Lake Ann
CITY OF
CHANHASSEN
7700 Market Boulevard
PO Box 147
Chanhassen, MN 55317
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L(!.,
MEMORANDUM
TO: Todd Gerhardt, City Manager
FROM:' Terrance Jeffery, Water Resources Coordinato~
DATE: ' November 23, 2009 l)~A
RE: Riley-Purgatory-BluffCreek Watershed District (RPBCWD) Request
for Variance from Internal Combustion Restriction on Lake Ann
PROPOSED MOTION
"The City Council approves a request for a variance from internal combustion
restriction on Lake Ann."
City Council approval requires a simple majority vote of the City Council
present.
BACKGROUND
On October 14,2009, the City received a letter from Mark Enochs ofCH2M HILL,
the engineer for the RPBCWD. This letter requested a variance from Section 6-51
of the Chanhassen City Code which reads as follows:
Sec. 6-51. Motors.
The operation of motorboats which are propelled by an internal
combustion engine is prohibited upon Lake Ann. The operation of
motorboats which are propelled by electric motors is permitted upon
Lake Ann.
The District wishes to sample and monitor the entire chain of Riley Creek lakes and
channels. Because Lakes Ann and Lucy are the origin for Riley Creek, the District
sees this is an important area to monitor.
The District is asking to complete the sediment oxygen demand sampling this fall
and to continue with additional monitoring from April through October of 20 1 0
through 2012. They anticipate needing to be on the lake two times per month but
may occasionally need more. In no month should they need to sample more than
once per week.
They will be measuring on-site parameters such aslight penetration, dissolved
oxygen, temperature and others as well as wet chemistry sampling. The wet
chemistry involves taking a grab sample from the lake to be brought to a laboratory
for analysis of nutrients and chlorophyll a.
Chanhassen is a Community lor Life - Providing for Today and Planning for Tomorrow
Todd Gerhardt
November 23,2009
Page 2 of2
Staff recognizes the benefit of this information. This information will be useful in
determining management of Lake Ann and the surrounding watershed. The
information which the District intends on gathering is typical water quality data
frequently gathered on area lakes.
RECOMMENDED CONDITIONS OF APPROVAL
. The boats shall clearly display the name of the organization responsible
for their operation and all persons shall have ID on them.
. The 24-foot pontoon boat with the 90hp outboard motor shall only be used
for the collection of sediment oxygen demand data.
. The boats shall remain no less than 150 feet from the ropes demarcating
the swimming area.
. All boats shall observe the 15 mile per hour speed limit for Lake Ann.
. The District shall observe Lake Ann Park's hours of operation which is
from 6 a.m. to 10 p.m.
. No power loading ofthe boats shall be allowed.
. No boats used for the purpose of sampling shall operate on Lake Ann on
days when lake-dependent community activities take place such as, but
not exclusively, triathlons and fishing contests.
. No boats used for the purpose of sampling shall operate on holidays.
. This permission shall only apply to the boats and operators listed in the
letter received from the Riley-Purgatory-Bluff Creek Watershed District
dated October 12,2009 and signed by Mark Enochs ofCH2M HILL. In
the event that staffing changes, the District shall notify the City in writing.
. The variance shall be reviewed annually and periodically as needed.
. The City reserves the right to rescind the permit at any time.
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