Ever since the Town of Lake Mills was established in 1845, township citizens and non-citizens alike have enjoyed all the benefits that Rock Lake has to offer. Among other things, this includes fishing, boating, swimming, kayaking or simply enjoying the pristine beaches at either Sandy or Bartels Beach.One of the main attractions of Rock Lake is the clarity of the water compared to other lakes in the area. However, in recent years, those enjoying the lake have come to question just how safe the lake’s water really is.
Two of the most obvious contaminants polluting the lake are E. Coli and excessive amounts of phosphorus. The beaches have been closed numerous times over the summers due to high levels of E. Coli. The most recent was in July. On this date, the E. Coli levels reached a high of 2419.6 cfu/100ml according to the weekly testing of the water by the Wisconsin State laboratory of Hygiene. To put that in proper context, the beaches are typically closed to swimming once the E. Coli levels reach 1,000 cfu/100ml. Although these type of E. Coli levels are not safe for anyone, it may be especially problematic for young children and people with compromised immunity systems.
So what exactly is causing these contaminates and where are they coming from? The simple answer is that some of the contaminants are a result of natural run-off that may be difficult if not impossible to avoid. With respect to E. Coli, it is typically caused by feces from birds and animals that live on or around the lake or from domesticated animals such as dogs and livestock.
Contaminants are deposited directly into the lake while others are caused from excessive run-off caused by heavy rains. In the case of excessive levels of phosphorus, it is typically caused by the depositing of agricultural fertilizers, manure and organic wastes in sewage, industrial effluent and even grass clippings. Soil erosion can also be a major contributor.
Phosphorus damages lakes by feeding the growth of toxic levels of algae and reducing the dissolved oxygen levels caused by an increase in mineral and organic nutrients. Once phosphorus settles in, it causes a lake to become eutrophic, a process in which rich amount of nutrients and minerals create excessive growth of algae. This reduces the lake clarity and impedes the growth of aquatic plants and oxygen levels that are essential for the survival and reproduction of the fish and reptile population.
Although, some sources of contaminants may be unavoidable, other sources may be eliminated or, at least, slowed to more acceptable levels. Such may be the case with regard to the Miljala Channel.
The Miljala Channel is a dredged public channel that feeds into Rock lake and is frequently used for fishing and kayaking by those who enjoy the lake. The banks of the channel contain 10 residential homes dating back to 1957. The contaminated water in the channel is derived from a stream flowing under Cedar Lane that was altered by local farmers so as to allow their fields to drain more quickly. Areas of land that were previously undeveloped, and absorbed some of the runoff, is now a paved parking area. Testing of the water in the watershed of the stream and channel have revealed high concentrations of phosphorus, nitrates, bacteria and other damaging pollutants. Oxygen levels in the channel have been depleted so badly by bacteria present that aquatic life has had to move out to the lake survive. The lake’s Bullrushes, critical for fish spawning and located at the opening of the channel, will likely be impacted as well.
Numerous studies have been done over the years to identify and recommend possible solutions to the problem but no action has been taken to stop the flow of contamination. In 1995, the Department of Natural Resources identified Rock Lake and was selected as a Priority Lake Project. The DNR funded project staffing and cost-sharing through 2004. The goals of the project were to reduce nonpoint source pollution through the implementation of conservation practices and preserve and restore important habitats necessary to sustain biodiversity, rare nongame species and sport fish production.
In 2013, the Rock Lake Improvement Association hired an engineering firm, to study the problem and develop a solution. Based on this study, a plan was written to follow once permission was gained for access from the landowners along the stream feeding Miljala Channel. As of the date of this article, such permission has still not been received from all of the landowners involved to access their land. As such, the problem has still not been resolved and the sediment and pollutants continue to flow into the channel at an increasing rate. It remains to be seen whether action will be taken before the damage becomes irreversible. The public is welcome and encouraged to voice their concerns with the Rock Lake Committee at one of their monthly meetings.