Water clarity on Lake Riley has never been better.

​Lake Riley Neighbors,


2020 has been a challenging year for all of us, so I thought I would bring a little good news to the forefront.

For some of you who have been living on or enjoying Lake Riley for years, you will recognize that the water this year has been exceptionally clear.   Some of you who are new to the lake may not realize what a big change this is.  In our first years here, in the mid 80’s, it was not unusual to have nearly opaque lake water this time of year.  On calm days, algae would float to the surface and drift to one side of the lake and the unfortunate residents on that side would be treated to a pretty strong smell.  As recently as August 2012 you couldn’t see your toes when standing in 2 feet of water. 

We have seen some great improvement over the last few years, but this summer is really tremendous.   Attached is a graph of the clarity measurements since 1992.  The red line is this year. What a difference!  

There are several factors that probably lead to this.   The University of Minnesota, along with our Lake Association and the Riley, Purgatory, Bluff Creek Watershed District, did an extensive study of managing carp, and ended up removing most of them.   Rice Marsh Lake now is managed to prevent reintroduction of young carp.    This year, a second application of Alum bound up more of the phosphorus in the water, and it certainly seems to have worked.   Maybe the presence of the early population of Zebra Mussels is helping to clarify the water too.    

Additionally, the lake weed population seems to have diversified, with less solid matts of Eurasian Milfoil. Aquatic plants were also studied by the University and some targeted management has been carried out by the watershed district.   I recall years of only coontail, milfoil and curlyleaf pondweed.  Now I see patches of several native lake plants, a good thing!

Let's hope that the trend continues and all do our best to protect our new clear water.

To all those that contributed over the years, thank you!

-John Bushey