Unexpected Color

Part of last week my wife and I made a trip to Northern Wisconsin. The visit included some biking, a little hiking, a visit with my brother, his wife and son, and to see the fall colors. We stayed at an Airbnb in St Germain, which was our first time using a vacation rental through Airbnb or Vrbo. The cottage we rented was on Lost Lake which is about half way between St Germain and Sayner. Overall, the fall colors were quite nice.  The colors may have been beyond peak, particularly for the colors in the eastern part of the county. The weather, even though cloudy for over half our time in the north woods, was still enjoyable with day time temps near the mid to upper 60's. We had a good time, and enjoyed the colors provided by the scenery of contrasting yellows, and reds with green of the pines and the (sometimes) blue sky.  There is one color, that I was not expected to see, and that was green. Not the green of pines and plants, but green on the surface of Lost Lake.  

The place we stayed

I am no expert on algae, but the oily consistency and the way it appeared seemed to be reminiscent of the toxic blue-green algae. It may or may not have been blue-green algae, but I was not going to risk swimming in the water with that gunk not knowing what kind of algae it was.  I did get one swim in on Thursday, before the overcast sky arrived, on a lake at the home of my brother. That water did not have algae, but did have some lily pads. I was not expecting the green surface of Lost Lake; it reminded me of some of the lakes in southern Wisconsin. 

Lost Lake

Funny, looking at the shore of Lost Lake, at least near the cottage in which we stayed, the lake did not have lily pads or any noticeable weeds by shore, and it had a nice sand surface. Yet, the nice sandy surface is no good for a swimmer with suspect algae present on the surface of the water.  The algae, from what I could see, did not have the blue tint common in blue-green algae, so perhaps it was not the toxic blue-green algae.  Like I said, it was tempting, but I was not about to risk it. 

Lost Lake Water

Algae growth is, generally, caused by too much phosphorus and/or nitrogen in the water. In the southern part of the state, algae blooms are quite common, in fact, I saw them occur on Lake Kegonsa in May, when I usually see them in June. The algae is common in the southern part of the state due to mainly to non-point sources of pollution.  Point sources are highly regulated, so they now contribute little phosphorus, but non-point sources, think agriculture, are not as highly regulated so runoff from farm fields and feed lots can make its way with its concomitant phosphorus and nitrogen into the streams and then the lakes.  Leaves are also a good source of phosphorus, and hence why my wife and I regularly clean our drive and street gutter of leaves. Many years ago, phosphorus was in detergents, but that was banned along time ago.  About eleven years ago phosphorus became highly regulated in fertilizers in Wisconsin, particularly lawn and garden fertilizers, so that source is much reduced. 

Lake a few Miles from Lost Lake
Undeveloped Shoreline and no algae noticed

Phosphorus is a very stubborn element, and holds, for example, to soil particles. That is one reason why Dane County has been sucking the muck out of the streams and rivers of the Yahara River--to get out legacy phosphorus in the element laden sediment. Agriculture, a common land use in the southern part of the state is a major contributor of phosphorus in the watersheds in the south half of Wisconsin.

Colors of the North WI Woods

The northern part of the state, particularly Vilas County, and nearby counties, have very little agriculture that would deposit phosphorus laden silt or other algae creating pollutants into water bodies. A small lake three miles away from Lost Lake, surrounded by state forest land had no discernible algae, nor did the small lake by my brother which has his home and three cottages. Both lakes would get leaves in the water from nearby trees, but this source can be discounted because leaves have been getting in these water since, well, creation. This brings up the question of, where did the polluting elements come from that affect Lost Lake? 

Lake in which I swam in Oct 7

Was it through an aquatic hitchhiker?  Maybe, but my theory is land use.  While the area lacks farms, many of the lakes have a good deal of development, and much of this development occurred before the advent of the shoreland protection ordinance, and more restrictive septic system requirements both mandated by the state in the 1970's. We know, from the Clean Water Act, that water can be cleaned, with education, regulations, and hard work. Think Lake Erie, which was once dead and is now back to life, but again threatened by pollutants related to agriculture use in the watershed. But, in northern Wisconsin, the most common land  uses are residential (mainly cottages or second homes), some businesses, forest and lakes. It is not called the north woods for no reason. One commonality is the rural characteristics of the land use. There are many unincorporated hamlets in the area, not to mention the lots that house cottages and now houses.  Most all with their own septic system. A septic system is usually a holding tank, with an infiltration bed.  Infiltration beds are required to have a a certain distance from the bottom of the discharge pipe to a restricting element, like ground water (noticeable by mottling in the soil). Yet, the ground of this area is sand, a lot of sand.  Sand, I feel, is rather fragile. Sand will infiltrate well, but that can be a problem, it can infiltrate too well and if the depth between water and soil is not sufficient, the pollutants will get into the ground water, and perhaps make their way to the lakes. Beds can age overtime, too, and go bad without a person even knowing it.  

Fall Colors on Lost Lake

My theory is that much has changed in the last 30 or so years up north. Cottages, which were owned by a single family often were occupied a few weeks out of the year, mainly in the summer.  Today, many are occupied year around, perhaps rebuilt and reconstructed as a more expansive dwelling--holding more people. Add in the vacation rentals, like we used, and one can see that the lake properties are being used much more than they used to be, which increases the risk of pollutants and elements like nitrogen entering the water, such as from septic systems. With this added burden, the resiliency of the lakes to offset or handle the pollution, is now not possible. Some of these residential buildings, or cottages, may have a failed septic system and do not even know.

Forest Lake Recreational Path, near CTH B

One possible solution, which has been used on other lakes in the state, is a sanitary sewer system.  Waste water would be collected and transported to a treatment facility.  Of course, this would be expensive, but what price should be put on clean water? I know Bear Lake in the Nicolet National Forest had blue-green algae this year (I was told that by a Forest Ranger with the Nicolet National Forest), and so it would not surprise me if Lost Lake's algae was also blue-green.  The unexpected color I noticed on Lost Lake could be a precursor to other problems that could beset the lake.

Oak tree

Planning and care need to be exercised to assure clean water, regardless of where it is located.  However, for the Wisconsin north woods, water is part of its economic life blood.  The lakes are one reason why people are drawn to the north woods, this is evidenced by so many home constructed along lake shores. The water, and woods, draw people, like my wife and I from the southern part of the state, and other states. People wish to recreate on, and in the lakes. This unexpected color on the lake surface could become problematic to the enjoyment and use of the lakes, and that would not serve any one well.