Green Lake And Duck Lake Association

PO Box 23

Interlochen, Mi. 49643

The association has had an active water quality testing
program for many years. Volunteers take water samples in
both lakes for  biological testing during the summer as well as  sampling bottom plants  to note changes in plant life and watch for the emergence of any invasive species such as  Eurasian Watermilfoil (EWM). We had a professional limnologist for many years, taking both  water and ottom soil samples and providing a full report on the lake complete with the data from previous years so we have a good picture of trends and any areas of concern.  The water testing program continues with volunteers, a professional lake management company and local water testing labs.

Go to the history page for a history of our lakes community

General Lakes Information

General Overview Green Lake

General Overview Duck Lake

Developing a Lake Management Plan

The Betsie River Watershed

It’s always good to remember that the watershed is more than just the piece we can see when we look at the lake.  Every drop of water that falls inside the dotted line that doesn’t evaporate will eventually go down the Betsie River to Lake Michigan at Frankfort.  Within that area are a number of lakes that are quite different.  Most lakes have water coming in and going out.  When measured, a “flushing rate” can be determined which means how long it takes to have the volume of water in the lake replaced by incoming water. Duck Lake has a “flushing rate” of 1.9 year, Green Lake is 2 years but Crystal Lake is over 20 years,  (What happens in Crystal stays in Crystal!). Very little water is coming in and very little going out.  The surrounding wetlands and springs make a big difference for Green and Duck lakes.  If you know the land surrounding Crystal Lake you know there are almost no wetlands around it and just one stream flowing into it.  All are in the same watershed but are quite different lakes. Click here for the complete 46 page Betsie River Watershed Hydrologic Study performed by Michigan Department of Environmental Quality in 2014.   See the Maps page for a high level map of the Betsie River Watershed

As long as we’re on the subject of water it’s probably a good opportunity to tell new people and remind the rest that the same wetlands and springs that we enjoy are what keep our lake levels relatively stable.  Do they change at all from year to year?  Certainly, but even with a very dry summer the wetlands, (think “sponge”) supply enough to keep levels within the normal range.  The same would not be possible at Crystal Lake.  The other variable is a dam.  Over the years several studies have been undertaken to see if the dams, one on the Little Betsie on the shoreline of Duck Lake and the other below Green Lake at the Grass Lake area, had any affect on the level of Green Lake.  The number of boards in or out of the dams, year around and readings taken at the Betsie River outlet on the lake were logged and the impact, if any, was noted.  The clear conclusion was that the effect of lowering Duck Lake in the fall had almost no impact on the level of Green Lake after a couple of days.  The same was true when the boards were replaced in the spring.  Green Lake didn’t drop as the wetlands gave up water to keep the flow rate the same.  The Grass Lake dam had no impact as it is too low to raise the lake level if the boards are put in and has a fixed spillway to handle any high volume of water.  The bottom line is neither dam has any control over Green Lake water levels.  The Duck Lake dam does control the level of that lake as it was designed to do.  837.3 feet was set by court order but an unofficial compromise has worked pretty well by lowering the level in the fall to avoid ice damage and raising it in the spring for the boating and peninsula canal needs.  The dams and their impact on lake levels appear to be one of those rare occurrences where

 Mother Nature has forgiven us for getting into her business!

DNR Fish stocking in Our Lakes

For a look at the DNR report on the amount and type fish stocking in our lakes over the years ting on the amount and type of fish the DNR has stocked in the lakes.  You can check the state web site.  (www.michigandnr.com/fishstock)  and  see stocking numbers for any lake in Michigan and exactly what has been planted since 1979.  The only variety they have put in Green and Duck lakes in recent years is Lake Trout.

Lake Trout, Brown Trout and Splake had been stocked here in the past. (Splake is a cross between a Brown Trout and a Lake Trout).  Our lakes are too warm for the Walleye, which they can plant in Long Lake.  Bass, Perch, Bluegill and other “pan fish” take care of themselves and don’t require stocking.  A fish survey is done about every 6-10 years to determine the type and number of fish present.

Water Quality

Click to view Water Testing Protocol

Click to view 2018 Green Lake WQ map

Click to view 2017 Green Lake WQ map

Click to veiw 2018 Duck Lake WQ map

Click to view 2017 Duck Lake WQ map

Water Clarity

Click here to see how we test clarity

A beginners guide to water management

Green Lake Clarity Testing Sites

2018 Water Clarity on Green Lake

2017 Water Clarity on Green Lake

2018 Water Clarity on Duck Lake

2017 Water Clarity on Duck Lake

Lake Levels

Click to view 2015 Preliminary Duck Lake Water Level Study

Maps

The maps page provides several BioBase maps of Green and Duck Lakes including; bottom composition, depth, and vegetation

Plant Sampling

Green Lake Plant Sampling Map

Duck Lake Plant Sampling Map

Common Native & Invasive Plant Pics

PLM Lake and Land Management Reports

Click here to view 2018 Green and Duck Lakes Year End Evaluation

Click here to view 2017 Green and Duck Lakes Year End Evaluation

Click here to view 2016 Green and Duck Lakes Year End Evaluation

Click here to view 2015 Green and Duck Lakes Year End Evaluation

Understanding DEQ Maps

Click here to view 2015 Duck Lake AVAS Survey - Detail

Click here to view 2016 Duck Lake AVAS Survey - Detail

Click here to view 2017 Duck Lake AVAS Survey - Detail

Click here to view 2018 Duck Lake AVAS Survey - Detail

Click here to view 2015 Green Lake AVAS Survey - Detail

Click here to view 2016 Green Lake AVAS Survey - Detail

Click here to view 2017 Green Lake AVAS Survey - Detail

Click here to view 2018 Green Lake AVAS Survey - Detail

Example of Property Owner Permission Letter

EWM Control Strategy Study

 

2016 Duck Lake Treatment Maps(June)

 

2017 Duck Lake Treatment Maps(Aug)

2018 Duck Lake Treatment Maps(June)

Biology and Control of Aquatic Plants -Will Herbicides Hurt Me or My Lake