Water Clarity: September 16, 2011

It was a beautiful clam, overcast, but chilly day on Lake Puckaway.  Temperatures have dropped to 60 degrees in the Lake and River reversing the heavy algae bloom of August.  Water clarity is slowly rebounding in the lake, but still poor, and upstream the Fox River is excellent with clarity at 8.75 feet!  For the first time the secchi disk hit bottom at the inlet, but was still clearly visible.  I would imagine the clarity there was in excess of seven feet.

Red indicates the secchi disk hit the bottom and total
water clarity depth cannot be measured.

2011 Emergent Plant Stabilization (EPS) Survey

Yours truly counting emergent plant stems,
in this case Stiff Arrowhead (Sagittaria rigida)

Once upon a time the East Basin of Lake Puckaway was nothing more than a river channel in a sea of wild rice and bulrushes that concealed the lake below.  Also in the shallows grew arrowheads, cane (Phragmites), sedges and cattails.  These are all emergent plants, which means a major portion of the plant sticks out of the water.  These plants are critically important to many fish and wildlife.  Northern pike only attach their eggs to vertical stems, so without this type of vegetation there could be no natural reproduction of northern pike.  Emergent and other vegetation also have a profound effect on water quality by holding sediment in place, dampening wave action, and several other mechanisms.  In parts of a lake the water clarity may be less than a foot while in a healthy bed of aquatic plants the water is much clearer.

Clear water in aquatic plant bed, Western Lake Puckaway.
Mid-lake the  water clarity was less than a foot.

Starting with the construction of the dam at Princeton, water level management began to have a slow but steady negative effect on emergent plants.  Coupled with poor agricultural practices and shoreland use, this eventually led us to a greater than 80% loss in emergent vegetation.  The Emergent Plant Stabilization project recognizes the importance of this habitat and the need to halt and reverse these losses.

As part a study to measure the current state of and recent trends in emergent vegetation, surveys are conducted on an annual basis since 2010.  Derek Kavanaugh and I surveyed vegetation this year on August 25th.  The tools are simple: a one meter sampling square made from PVC pipe, something to measure water depth, and field guide to aquatic and wetland plants.  Together we estimated the total coverage of floating leaf plants, the coverage of submergent plants, and counted the stems of the emergent plants in three study areas.  A comparison of 2011 and 2010 will appear in a future post.

Derek using the GPS in the LPPRD's work boat.

Emergent Plants in the Survey

Stiff arrowhead, Sagittaria rigida

Soft-stem bulrush, Schoenoplectus acutus 

Giant Reed (cane), Phragmites australis

Pulling the boat through shallow water to another survey point.

Water Clarity: August 31, 2011

This was the last day of the season for monitoring phosphorous, chlorophyll a (a measurement of algae) and several other variables. When I receive the all the test results from the state lab, I'll report them here.  In the mean time I will continue to get water clarity readings every two weeks to see how the lake clears up as winter approaches.  As the temperatures cool, and the days get shorter the algae will begin to die down and the water will clear up.