02-12-2014
Chanhassen Environmental Commission (EC)
Regular Meeting
February 12, 2014
Members Present:
Glenn Kaufmann, Matthew Myers, Katie Mahannah, Bret Borth, Keith Anderson, Amy
Omann, Amy Wenner
Members Absent:
none
Staff Present:
Jill Sinclair, Environmental Resource Specialist, Terry Jeffery, Water Resources Coordinator
Guests Present
: Diane Spector, Water Resources Planner, Wenck Engineering
Minutes:
January minutes were approved.
Sustainability Report:
Katie led the review of the sections. She thought all of them looked good. The Urban
Forestry section was still missing. The commission talked about making the stormwater and surface water
sections two pages each, water conservation could be a half-page and urban forestry could be one-half to one-
page. Katie reminded everyone that final drafts are due by March 1. After Katie gets all of the sections back
from the commissioners she’ll do the editing and formatting and re-publish it as a Google document. She will be
incorporating manuals, policies, etc that are referenced in the sections into the introduction. The report will be
discussed one last time at the March meeting.
Surface Water Management Plan Citizens Advisory Committee:
Terry introduced the topic and noted that the
schedule is a little behind, but that the timing for the public review is still doable. He stated that the primary goal
of the Surface Water Management Plan (SWMP) is to improve water quality. Tonight, he said, the commission
will be educated on the two Use Assessment and Attainability (UAA) reports for Lakes Susan and Ann. Both
lakes are in the same watershed so they tie in together nicely. Terry introduced Diane, who presented at the
October commission meeting. Diane opened her presentation by explaining that the UAAs for Lakes Lucy, Ann
and Susan provide background on water issues affecting those lakes and demonstrate how water quality issues
were identified. Lake Lucy has a contributing watershed of 909 acres; Ann has 131 acres and Susan 1281 acres.
The real contributing watershed area to Susan is a sum of all 3 lakes. When hydrologic modeling is done, rather
than looking at the overall watershed, the modeling looks at neighborhood-sized areas. For water quality,
measurements are taken for total phosphorous (P), chlorophyll A, and secchi disc depth. Lake Lucy has the
highest concentration of P, therefore it’s contributed to Ann downstream. The goals of the Riley-Purgatory-Bluff
Creek Watershed District are based on deep lake standards (<40 ppb) which are hard to meet for shallow lakes.
Shallow lakes have different state standards (<60 ppb). For example, Lucy has 90-95% littoral (shallow) zone so
it’s very hard to achieve deep lake water quality goals. (40 and 60 ppb correlate to algae bloom and
transparency.) If the state standards are exceeded then a Total Maximum Daily Load (TMDL) and other measures
are required. A natural lake in central MN is usually mesotrophic; eutrophication can happen even in the absence
of human impact. It’s important to look at long term trends and data for lakes. Algae blooms can happen within a
couple of days after a rain event and an influx of P into a lake. If measurements are taken then, the data will
suggest that the lake is worse off than it is.
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The Lake Susan watershed is broken down into smaller and smaller areas in order to look at land use and run off.
Calculations are made from corresponding tables or site observations. This is done to help estimate the watershed
load (i.e. what’s coming into a lake from outside areas) A budget is then constructed to look at how much is
coming from different sources such as atmosphere, sub-watersheds, internal load, upstream lakes, and directly.
The internal load comes from sediment and aquatic vegetation sources. The less oxygen in the sediment the more
nutrients will be released. The internal load can be estimated by taking a dissolved oxygen profile. The P budget
for Susan shows that 182 pounds of load reduction is needed each year. Modeling can help identify generally
where most of the load is coming from.
Lake improvement strategies:
Lucy: iron enhanced sand filtration on existing ponds (aka MN filter); spent lime treatment; whole lake
alum treatment; curlyleaf pondweed treatment
Ann: whole lake alum treatment
Susan: iron enhanced sand filtration on exiting ponds; increase storage; whole lake alum treatment
Other actions for water quality improvement:
-plan for future development - ensure additional development has adequate water quality treatment
-stabilize stream corridors - maintain habitat for game fish
-coordinate with public entities - implement BMPs with highway and street reconstructions, continued
support for street sweepings
-education and outreach – community rain gardens
-continued wetland and pond monitoring – P sampling, dissolved O sampling
Terry said that he’d be back in front of the commission in April. He will have the modeling done and it will be
time to figure out how to incorporate education and outreach.
General Discussion
:
As a project planning update, Glenn shared that the DNR received a grant to clear buckthorn and
undesirable species at the Seminary Fen. Glenn contacted Larissa and asked her about the commission
future involvement with the fen. He will report back to the commission when he hears from her.
Amy was at the Minnehaha Creek Watershed meeting and heard there is a lecture series on how to
capture stormwater. They have pilot projects on capturing rainwater and reusing it. It’s the best option
where there are high water consumption and class D soils. She was wondering if there are opportunities
in Chanhassen for it. Terry said that the Hwy 101/61 project may have a water reuse feature in the
roundabouts for irrigation. He has also talked to the Parks Dept. about reuse options.
Amy O shared the World Population Clock – a fascinating countdown of births, deaths, etc around the
world. www.poodwaddle.com
Matthew will be absent from the March meeting.
Amy O will work on compiling a new commissioner information packet.
Meeting adjourned at approximately 7:45 PM.
Minutes prepared by Jill Sinclair
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