Stormwater is the result of rainfall or snow melt, and it has a major impact on the quality of our lakes and rivers. Following a precipitation event, stormwater flows over ground surfaces and collects whatever is on them sediments, excess nutrients, chemicals, bacteria, and the like. These polluting substances are dissolved in and carried with the stormwater.
Nutrients are a necessary component for growth, but when it comes to lakes, an excess of nutrients can mean too much growth. In a natural lake system, nutrients such as nitrogen and phosphorus are limiting factors, and algae is therefore only able to reproduce until it runs out of these nutrients. With development, however, nutrients are released into the lake in much greater quantities. Fertilizer and sewage have historically been notorious for their high nutrient contents.
In areas of natural ground cover, such as prairies or forests, the dirty water is cleaned before it reaches the lake. The soil acts like huge water filter, soaking in the dirty stormwater and filtering out contaminants and the purified water will then make its way into the groundwater or other surface waters such as lakes.
The problem in Amery, however, is that with development, most of these natural ground covers have been disturbed or replaced by hard surfaces.
Development inevitably leads to disturbed areas and impervious surfaces. When rain falls on these areas, the stormwater is unable to soak into the ground, so it, along with all the polluting substances it picks up, flows into our lakes over the ground surface or through the storm sewer system.
Disturbed areas contain exposed soil, often due to construction projects or frequent use, and are particularly prone to erosion problems.
Impervious surfaces are hard surfaces that do not allow the infiltration of water; they may include roofs, decks, driveways, sidewalks, or high traffic areas of lawn where the soil has been compacted.
Water quality is directly dependent on water in the area, including stormwater runoff, that flows into the lakes. Since every developed lot contains at least some disturbed areas or impervious surfaces, every lot in the Amery Lakes drainage area contributes to the quality of stormwater runoff that reaches the lakes.
The addition of polluting substances is detrimental to the health of the lakes and their inhabitants, both human and non-human. Negative effects include the presence of undesirable aquatic plants and algae blooms in the lake. Take phosphorus, for example. This nutrient is contained in many fertilizers and decaying plant material such as grass clippings, which inevitably make their way into stormwater runoff. Stormwater containing a single pound of phosphorus can result in 500 pounds of algae growth in the lake.
Important: 1 pound of phosphorus can lead to 500 pounds of algae.
Do Your Part
Diversion practices prevent stormwater from flowing directly into a lake by redirecting the water into infiltration areas such as rain gardens or rock trenches, which allow the water to soak into the soil.
The potentially harmful effects of stormwater can be alleviated through the use of diversion and infiltration practices such as:
Native vegetation buffers
All discourage erosion and sedimentation, while promoting the infiltration of stormwater into the soil. Through infiltration, the water can be purified before it reaches the lake.
Diversion and infiltration practices also have many secondary benefits, such as reducing the need to mow lawn grasses and keeping geese off your property.