|Contact Me: Kathy Mortensen ...
826 121st St.
Amery, WI. 54001
WATER QUALITY REPORTS ...
for the SIX largest lakes in Polk
Data from Wisconsin DNR Website
Lake Wapogasset /Bear Trap
Big Round Lake
|click on WATER QUALITY REPORT below for pdf file
Water Quality – What we have tried so far (and has it worked?)
Since at least the 1940’s, one of the principal functions of the Sanitary District
has been to monitor water quality. As part of a 2-part series, I’d like to outline
steps that have been taken in an attempt to protect/improve water quality in our
Over the next many years, copper sulfate was introduced into our lakes for weed
management. This practice was little more than a bandaid and a potentially
dangerous one at that as copper is a heavy metal. In 1999, after several years of
investigation by the Lake Assn, it was decided to treat the lakes with alum. The
alum was to bind with the phosphorous in the lake sediment so that it could no
longer be released into the water column. Projections were that the alum would
hold the sediment for 8-10 years. In fact, water quality was only improved for 2-3
years. It was determined that, although DNR recommendations were followed,
the amount of alum applied was not sufficient to bind the phosphorous. This
treatment cannot be said to have been “successful” as a long term solution.
For many years, the District has contracted to analyze the incoming tributaries to
determine how much external loading is received via that route. This analysis is
far more than just an academic exercise since it allows us to target specific areas
to work. The analysis has resulted in an the accumulation of an immense library
of information about our lakes, what can and possibly will work to improve clarity
and what will likely not be of benefit to us.
The purpose of weed control is not to improve water quality per se, but instead to
control growth which can interfere with recreational use of the lakes. In 2008, we
initiated a plant survey and found a large amount of an invasive plant species
known as “curlyleaf”. The past 4 years, in cooperation with the Lake Assn, we
attempted to reduce the curlyleaf population by applying herbicide to specific
beds as approved by the DNR. This experiment had mixed results with some
beds responding well one year and not affected at all the next year. Due to the
inconsistent results, the District elected not to continue the project in 2013.
Instead, we are exploring weed harvesting which would physically remove the
invasive curlyleaf before it has a chance to die off and release phosphorous. T
We have ordered another plant survey for this month and will report results as
soon as available.
We have another program in place to monitor for Eurasian Milfoil. This is an
extremely damaging invasive species that has found its way into Polk County.
Thru volunteers, our lakes are monitored weekly throughout the summer for
milfoil. Thankfully, so far none has been found. This year we have joined with
the Lake Assn in its Clean Boats/Clean Waters monitoring program. The District
has received a grant to fund the program which will mean more consistent
reviews will be done. The volunteers who have worked the landings in the past
deserve some reinforcements and a break from their efforts.
Our greatest ability to improve water clarity lies with the individual property
owner. If you fertilize your lawn, be sure the product contains no phosphorous
(the middle number on the bag). Do not burn within 75 feet of the lake. If you do
have a campfire on your shore, remove the ashes immediately so there is no way
for them to wash into the lake.
Analysis: If we were to rate our efforts in maintaining/improving water quality,
results would be mixed. Projects that have been undertaken have certainly
resulted in some long term water quality improvement. This improvement is
especially notable when one looks over the past decades vs the last 5-10 years.
Most projects have only had short term benefits. Our objective remains to seek
to achieve a steady and consistent reduction in the number of days that the lakes
are plagued by occurrences of algae.
All of the projects that have occurred on our lakes have been because of the
work of many, many dedicated volunteers. Ongoing monitoring of water clarity is
imperative to understanding how the lake functions. Don’t wait to be asked –
volunteer to be on the Assn’s Lake Improvement Committee. The future will
Dave Erspamer - President - Lake Wapogasset Bear Trap Sanitary District
JULY 10, 2013
Lake Wapogasset Bear Trap Sanitary District