Nutrients are essential for the health and growth of living organisms. In aquatic ecosystems, they play a crucial role in supporting the development of phytoplankton, algae, and other primary producers, which form the foundations of the food web. Essential nutrients like nitrogen and phosphorus help these organisms thrive, fueling vibrant and productive ecosystems.
However, when these nutrients are present in excessive amounts, they can lead to significant problems. Nutrient loading, the process by which excess nutrients enter water bodies from sources such as agricultural runoff, wastewater discharge, and industrial activities, can overwhelm aquatic systems. This surplus triggers a range of ecological issues, including harmful algal blooms, oxygen depletion, and disruption of aquatic life. Cyanobacteria blooms are a direct result of excess nutrients in a water body.
While the Wentworth Watershed may lack industrial and agricultural contributors, there are many sources of excess nutrients present from household cleaners to road maintenance. To learn more about specific sources, move your mouse around the graphic below and click on different items to see how they contribute to or mitigate nutrient loading.
Nutrient Loading Infographic
Explore the causes of nutrient loading and some mitigation methods by mousing around this image.
Boats and Invasives
Boats can discharge or leak fuels that contain nutrients. Propellers stir up sediment at higher speeds, reintroducing settled nutrients into the water. Boats used in other water bodies can unintentionally introduce invasive species to the lake. Invasive species alter the natural nutrient cycle, leading to nutrient overload. Proper boat maintenance and minimizing wake can help reduce these risks.
Roads and Driveways
Rainwater runoff picks up excess nutrients from chemicals applied for snow and ice control. Additionally, sediment and organic matter from deteriorating pavement and loose gravel can wash into storm drains or streams, transporting nutrients to lakes. Regular maintenance, such as sealing cracks, reducing chemical use, and implementing erosion control measures, can help minimize these nutrient inputs.
Shoreline Erosion
Wind-driven waves, fluctuating water levels, and ice expansion in colder climates contribute to wear on the shoreline. Activities like boating and construction can accelerate erosion by destabilizing soil and vegetation. When shorelines lack native plants that hold soil in place with their roots, they become more susceptible to erosion. Planting native vegetation along the shore can create buffer zones to limit impact and reduce erosion.
Household Causes
Septic systems, when malfunctioning or improperly maintained, can release high levels of nitrogen and phosphorus, which may then leach into streams and lakes. Many household cleaners and detergents contain phosphates and other chemicals that can enter waterways through household wastewater. Choosing phosphate-free products, maintaining septic systems regularly, and minimizing the use of harsh cleaning agents can help reduce this nutrient load.
Rain Garden/ Runoff Prevention
Rain gardens and runoff infiltration are effective for reducing nutrient loading in lakes. Rain gardens are shallow, planted depressions designed to capture and absorb rainwater runoff from impervious surfaces. Rain gardens slow down the water and allow it to seep into the soil, reducing the flow of nutrient-rich runoff. The plants and soil in a rain garden naturally filter out pollutants, including excess nitrogen and phosphorus, preventing these nutrients from reaching lakes.
Shoreline Vegetation Buffer
Shoreline vegetative buffers, composed of native grasses, shrubs, and trees planted along the shoreline, act as natural filters for runoff flowing toward the lake. Vegetative buffers slow down this flow, allowing the plants and soil to trap and absorb excess nitrogen, phosphorus, and other pollutants before they enter the water. The root systems of these plants also stabilize the soil, reducing erosion and sedimentation.
Fertilizer
Fertilizers are nutrient-rich as they are formulated to provide phosphorus and nitrogen to plants. Improper application and overfertilization result in excess nutrients that aren’t taken up by plants which can wash off of lawns and gardens after rain or watering and flow into water bodies. Choose the right fertilizer, consider natural methods such as lawn clippings, and follow guidelines to ensure safe application to reduce the nutrient load.
Pet Waste
Pet waste left on the ground can be washed into nearby streams, storm drains, or directly into lakes. Pet waste is high in nitrogen and phosphorus and often contains harmful bacteria and pathogens that degrade water quality and pose health risks to humans and wildlife. Pet waste should be bagged and placed in the trash for proper disposal.
Management and Prevention
Managing the nutrient levels of our lakes starts outside of the water body. Preventing excess nutrients from getting into the water is the most effective way to prevent overload.
Part of the prevention process is public education. Many people assume that because nutrients are natural they cannot be harmful to the ecosystem. Dispelling these myths and helping communities understand the consequences of producing or applying excess nutrients on their property or within the watershed is an important step in changing behaviors that lead to nutrient loading in lakes.
Another important piece of the puzzle is advocacy. Working with communities and government structures on local and state levels can help us develop and enact policies that can moderate nutrient loading. To see an example of a grassroots advocacy effort that resulted in a policy regarding septic system health, check out this post from our blog.
See our watershed management plan page to read about our actions to mitigate concerns to lake health, including nutrient loading.
Consider making upgrades to your own property to protect the health of the lakes and watershed. See our lake-minded resources, and consider signing up for a lake-minded consultation, where our organization and partnered experts will work with you to enhance your property for lake health and often your own enjoyment.