If you were on or around the lake in early June you would have seen a pretty clear (almost blue) body of water, raising your anticipation for fun and lake enjoyment!! However, the later half of June brought two significant rain events in Southern Wisconsin that have had a negative impact on Lake Delavan! One even accompanied by a tornado!
As we mention on the website all the time, Delavan lake is a “drainage” lake, which means all the water in the lake comes from either the shore, tributaries (like Brown’s Channel or the Inlet), or rainfall!
After a rainstorm, lake water can appear brownish due to several reasons:
1. Runoff and Sediment: Rainwater often carries soil, silt, and organic matter from the surrounding land into the lake. This sediment can make the water appear brown or murky.
2. Erosion: Heavy rainfall can cause erosion of nearby banks and shorelines, adding more sediment and organic material to the lake.
3. Tannins: Decaying leaves, plants, and other organic matter can release tannins into the water, which can give it a brownish color. Rain can wash these materials into the lake.
4. Algae and Plankton: Storms can stir up the water, causing a bloom of algae or an increase in plankton, both of which can change the color of the water.
5. Pollutants: Urban runoff can carry pollutants such as oil, grease, and other chemicals into the lake, affecting its color.
Most of this impact is seen along the shoreline, due to shallower waters and accumulating solid materials!
So Blue Lake Turns to Brown Lake!
This could be the end of the story if those suspended solids would just settle to the bottom of the lake and allow everything to go back to normal… but it is not!
Unfortunately, a higher degree of plant growth promoting material (like phosphorus from the lake bottom or surrounding watershed) rushed into the lake. Subsequent warm temperatures, sunshine and calmer waters created an “algae on steroids” effect!
So Brown Lake Turned into Green Lake!!
What we have seen in recent week is a green lake, due to a high degree of suspended algae in the lake. In some areas, especially where the water flow is more stagnant, the green algae has turned to “Blue-green Algae Blooms “ which isn’t really algae at all, but an over growth of natural bacteria. These blooms can produce toxins that are harmful to animals, humans, and the environment, causing health issues such as skin irritation, respiratory problems, and even liver damage if ingested.
Green Back To Blue
Hang in there, we are on our way back to cleaner water! With cooler temperatures and some moderate rainfall, things should reset. This cycle has repeated itself in the past!
The keys to improving the frequency and intensity of these cycles is accomplished through improved land management in the watershed that feeds water into the lake!!
More on that next time!!
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