by Wynn Muller – Maine Lakes Society

As an active lake association, Friends of Wilson Lake spends about $5,000 (including $2,000 in DEP grant funds) inspecting boats at the landing to prevent the spread of milfoil and other invasive plants into our lakes. You also might know that we have been fostering and promoting LakeSmart, as evidenced by the many LakeSmart signs around the lake. You might ask…why we do this? What good are LakeSmart houses and why spend so much money inspecting boats? If we only inspect on weekends, what about all those boats launching mid-week? These are all valid questions and I’ll try to provide some answers to help your lake association move forward with building support for similar programs to protect your lake.

Invasive Plants and Boat Inspections

Invasive plants are one of the biggest threats to water quality and lake health, and we have talked much about the dangers, threats and impacts from invasive aquatic plants over the years. They are the reason the Courtesy Boat Inspection Program exists. And our fear about what might happen when they arrive is why we devote so much money toward it. While we cannot afford to inspect every boat, the fact that we maintain a weekend presence at the launch goes a long way toward stressing to most boaters that it is necessary to inspect your own boat to make sure you do not bring invasive plants to the lake.

Phosphorus & LakeSmart

Phosphorus is another of the biggest threats out there to lake health. Here is my simplified version of why that is true. Nutrients are essential for all life, including algae. That is why we provide fertilizer on flowerbeds, to feed our plants. The first two nutrients listed on the fertilizer bag are nitrogen and phosphorus. While nitrogen can make an algae bloom worse, it does not cause the algae bloom to commence.

To initiate an algae bloom, the lake needs phosphorus. For lakes, the main source of phosphorus is erosion. Dirt, soil, rocks and gravel all contain phosphorus, so the erosion or runoff from road ditches, camp roads, shorelines, agriculture fields and forest harvesting are all carrying phosphorus-laden dirt. Phosphorus also can come from manure, fertilizer, and septic systems.

Generally, lakes can handle a phosphorus level of less than 10 ppb (parts per billion, less than 0.000001%). However, when that level is exceeded to perhaps a level of 20 ppb, algae growth may start to turn the water green. That is the impact of a minute additions of phosphorus to the lake. Wilson Lake has an historic phosphorus level of 8 ppb, good but still in danger. I do realize this is a rather simplified version of why phosphorus is harmful to the lake but you get the picture. Keeping phosphorus out of the lake is one of the main reasons we so strongly support LakeSmart.

So how does LakeSmart help keep phosphorus out of the lake? The LakeSmart program looks at four different aspects of each property. First, we look at the driveway and parking area for signs of erosion. If so, where and why is it happening and what can a landowner do to direct runoff into buffered areas away from the lake?

Second, we look at structures and septic systems. If the septic system is not working, the property cannot be LakeSmart until it is repaired or replaced. The structure is also examined for signs of roof runoff. If the roof runoff goes into a rock or vegetated area, the erosion is minimized. It can also be directed into a “rain garden,” where the water gets a chance to filter down into the earth and not flow directly into the lake.

The other two areas are the yard and shorefront. We look at both areas to make sure that runoff does not flow directly into the lake. Wide buffers of vegetation along the shorefront that filter the nutrients from the water before it can reach the lake are best. An ideal buffer consists of multiple levels of vegetation — canopy (high), shrub (mid), understudy and ground cover (low) as well as a layer of duff (leaves and organic material on the ground) — that slow water flow and reduce stormwater flow into the lake. This reduces the impact of rain, while the root structures help absorb the flowing water. LakeSmart homeowners also minimize the use of pesticides and fertilizer to keep additional chemicals that foster algae growth out of the lake. They also look at the stability of shorefront banks. For every area raising concern, LakeSmart helps homeowners identify solutions and plan for long-term property management that reduces erosion.

Bottom Line

I took an online course on Watershed Stewardship. The instructor was Laura Wilson from the Maine Cooperative Extension. Her comments were, “The big two, as far as lake threats, are phosphorus and invasive aquatic plants.” Lakes infested with invasive plants and overloaded with phosphorus reduce our ability to boat, fish and swim; the quality of wildlife habitat; and the scenic beauty of our lakes. Property values and the resultant tax base are also affected by declines in water quality. From a study done by the University of Maine, a 3-foot (one meter) decline in water quality can result in a decline of 10 to 20 percent in shorefront property value.

The work that lake associations do is most important to the future quality of our lakes. Supporting courtesy boat inspections and building LakeSmart programs are great ways to insure against future declines in water quality. We may not see immediate improvement to water quality. That is okay as we want to see no signs of water quality reductions. The Council of Lake Associations at Maine Lakes is here to help all of us build programs, add members, and protect our lakes.

I hope these explanations and answers get you on your way to building lake programs wherever you are.