Monday: Stormwater 101
Have you ever wondered what causes stormwater runoff and pollution?
Continue reading to learn the fundamentals of stormwater runoff, its impact on our environment, and the measures we can all take to reduce stormwater pollution. Understanding the basics of stormwater runoff and pollution can protect our local waterways and contribute to a healthier, more sustainable Wisconsin.
Join residents from around Wisconsin as we explore Stormwater 101!
What is Stormwater?
Stormwater refers to the water that originates from precipitation events such as rain or snowmelt. When it falls on impervious surfaces like rooftops, roads, and sidewalks, it cannot soak into the ground and instead becomes stormwater runoff. Stormwater runoff flows over these hard surfaces, eventually finding its way into drainage systems, streams, rivers, and lakes. Essentially, stormwater runoff is the excess water that does not get absorbed into the soil.
Why Does Stormwater Runoff Matter?
Stormwater runoff might seem harmless, but it can have significant environmental consequences. As it flows over streets, sidewalks, and other impervious surfaces, stormwater can pick up various pollutants, including sediment, chemicals, oils, phosphorous, fertilizers, salt, and bacteria. Stormwater runoff that goes down storm drains does not go through any treatment processes to remove contaminants before being discharged into local waterways in most communities across the state of Wisconsin. When this polluted runoff enters our waterways, it can degrade water quality, harm aquatic ecosystems, and pose risks to wildlife and human health. Understanding the impact of stormwater pollution is crucial for protecting our water resources, preserving biodiversity, and ensuring the availability of clean water for future generations.
By learning more about stormwater and its implications, we can proactively manage it effectively and prevent pollution. In the next section, we will explore how stormwater runoff occurs and the factors that influence its rate and volume.
What Causes Stormwater Runoff?
Stormwater runoff behaves differently depending on whether it falls on natural or impervious surfaces. Natural surfaces, such as forests, farmland, and grassy areas, have vegetation and soil that help absorb a significant amount of rainfall and snowmelt, allowing it to gradually soak into the ground. In contrast, impervious surfaces, such as roads, parking lots, sidewalks, driveways, patios, and buildings, do not allow water to penetrate the ground, resulting in increased runoff. As urbanization and land development expand across the state, impervious surfaces replace natural ones, increasing the volume and speed of stormwater runoff and leading to various challenges in managing it effectively.
What is a Watershed and How Does it Help?
Watersheds play a crucial role in stormwater runoff. A watershed is an area of land where all the water that falls within it, including stormwater, converges and flows into a common water body, such as a stream, river, or lake. Watersheds can be large, encompassing multiple municipalities, or small, covering just a few square miles. Understanding the watershed boundaries is essential because the actions taken within a watershed affect the quality and quantity of stormwater runoff in that area. By managing stormwater at the watershed level, we can implement comprehensive strategies to protect and improve water quality throughout the entire state.
Did you know? Wisconsin has over 330 watersheds and 32 drainage basins.
What Factors Affect Runoff Rate and Volume?
Several factors influence the rate and volume of stormwater runoff:
Rainfall Intensity: The amount and intensity of rainfall directly affect the rate at which stormwater accumulates and flows over surfaces. Heavy or prolonged rainfall events can lead to increased runoff.
Soil Type and Condition: Different soil types have varying infiltration (absorption) rates. Sandy soils allow water to infiltrate more quickly than clay soils, which have a slower infiltration rate. Compacted or saturated soils further reduce infiltration capacity, increasing runoff.
Topography: The slope or gradient of the land influences the speed at which stormwater moves. Steeper slopes accelerate runoff, while flatter areas allow more time for infiltration.
Vegetation Cover: Vegetation, such as trees, grass, and shrubs, plays a vital role in managing stormwater. Vegetative cover helps intercept rainfall, promotes infiltration, and reduces runoff by absorbing and slowing down water flow. Native plants that have longer root systems help absorb even more stormwater runoff and are a good addition to a rain garden. You can learn more about rain gardens during our webinar.
Land Use and Development: Urbanization and land development significantly impact stormwater runoff. The presence of impervious surfaces, such as roads and buildings, reduces infiltration and increases runoff. Proper stormwater management practices in developed areas are crucial to minimize the negative effects of increased runoff.
Understanding these factors helps us identify areas where stormwater management interventions are needed. In the next section, we will explore the common sources of stormwater pollution, shedding light on the substances that can contaminate our water bodies.
What are Sources of Stormwater Pollution?
Common sources of stormwater runoff pollution include non-point and point source pollution. Below we breakdown these sources of stormwater pollution and how you can help prevent these from entering our waterways with things you do around your home or business.
Non-Point Source Pollution:
Non-point source pollution refers to stormwater pollution arising from various sources rather than a single identifiable point. These sources contribute pollutants to stormwater runoff, which can ultimately contaminate our waterways. Some common non-point sources of stormwater pollution include:
Sediments and Soil Erosion: When rainwater flows over bare soil or construction sites, it can dislodge and carry away sediments. These sediments can contain pollutants such as heavy metals, pesticides, and nutrients, negatively impacting water quality.
Chemical Contaminants: Chemicals from various sources can enter stormwater runoff, including oil and grease from roadways, pesticides from lawns and gardens, and chemicals from industrial activities. Properly maintaining your vehicle and reducing pesticide use can help reduce these contaminants that otherwise can harm aquatic life and ecosystem health.
Phosphorus and Nutrient Runoff (Fertilizers): Excessive use of fertilizers on lawns and gardens, as well as grass clippings or leaves left in streets, can lead to nutrient runoff, particularly nitrogen and phosphorus. When these nutrients enter water bodies, they can cause harmful algal blooms, deplete oxygen levels, and harm aquatic organisms.
Pet Waste: Pet waste left on streets, sidewalks, or lawns can wash into storm drains during rainfall, introducing harmful bacteria and pathogens into our waterways. Proper disposal of pet waste is essential to prevent contamination. After all, you wouldn’t want to swim with your pet’s waste would you?
Point Source Pollution:
Point source pollution refers to stormwater pollution from identifiable and discrete sources, such as pipes, outfalls, or specific industrial facilities. While point source pollution is regulated under various environmental laws, it can still contribute to stormwater pollution. One common form of point source pollution in stormwater is referred to as an illicit discharge. Illicit discharges are unauthorized or improper releases of pollutants into storm drains or water bodies. These can include improper disposal of chemicals, dumping of hazardous substances, or illegal connections to stormwater systems. Illicit discharges can introduce a wide range of pollutants into our waterways, posing risks to aquatic ecosystems and human health.
By understanding these common sources of stormwater pollution, we can take proactive measures to mitigate their impacts. In the next section, we will explore the environmental consequences of stormwater pollution, emphasizing the importance of addressing this issue effectively.
What are the Environmental Impacts of Stormwater Pollution?
Stormwater runoff pollution can have significant environmental consequences, affecting both aquatic ecosystems and human health. Here are some key impacts of stormwater pollution:
Water Quality Degradation: Pollutants in stormwater runoff can degrade the quality of our water bodies. Excess sediments can cloud the water, hindering sunlight penetration and affecting aquatic plant growth. Chemical contaminants can be toxic to aquatic organisms, leading to reduced biodiversity and disrupting ecological balance.
Harm to Aquatic Ecosystems: Stormwater pollution can harm fish, amphibians, and other aquatic organisms. Chemical pollutants, such as heavy metals and pesticides, can accumulate in the tissues of these organisms, causing physiological damage and impairing their reproductive capabilities. Nutrient runoff can trigger excessive algal growth, leading to oxygen depletion and creating dead zones where aquatic life cannot thrive.
Effects on Human Health: Stormwater pollution poses risks to human health, primarily through the contamination of water supplies. Pathogens from pet waste and other bacteria can make water unsafe for swimming or drinking. Chemical pollutants can also find their way into drinking water sources, posing long-term health risks if consumed.
How Can You Help Keep Our Waterways Clean?
As individuals, we can take several actions to mitigate stormwater pollution at the residential level:
Rain Collection: Use rain barrels to capture stormwater runoff from your rooftop and plant a rain garden to help absorb more runoff in your yard. Learn more about stormwater Rain Collection.
Responsible Lawn and Garden Care: Use fertilizers and pesticides sparingly and follow the recommended application rates. Maintain healthy lawns and gardens, as healthy vegetation helps absorb and filter stormwater. Learn more about stormwater and our Leaves and Lawn Care topics.
Proper Disposal of Household Chemicals: Dispose of household chemicals, motor oil, and other hazardous substances at designated collection points to prevent them from entering storm drains. Never dump anything down a storm drain. Learn more about Only Rain Down the Drain.
Managing Pet Waste: Pick up pet waste and dispose of it properly in trash cans or designated pet waste stations. This prevents bacteria and pathogens from being washed into storm drains. Learn more about Only Rain Down the Drain.
Wisconsin communities, businesses, and industries can adopt best management practices (BMPs) to minimize stormwater pollution:
Implementing Best Management Practices (BMPs): Employ strategies like sediment controls, stormwater ponds, and vegetated swales to capture and treat runoff before it enters water bodies.
Effective Stormwater Infrastructure: Maintain stormwater management infrastructure, including catch basins, retention ponds, and filtration systems, to ensure proper functioning and pollutant removal.
Stormwater Regulations and Policies: Develop and enforce stormwater management regulations and policies that require responsible construction practices, proper maintenance of stormwater systems, and compliance with pollutant discharge limits.
By adopting these best practices at various levels, Wisconsin residents can collectively reduce stormwater pollution and preserve the health of our water resources.
Now What?
Understanding the basics of stormwater runoff and pollution is crucial for protecting our water resources and creating a sustainable future.
We can make a significant difference in reducing stormwater pollution by adopting responsible residential practices, implementing best management practices in commercial and industrial settings, and community-wide efforts. Check out our other daily topics to learn more about how you can make a difference!
Wisconsin Stormwater Week, from August 5th to 13th, 2023, provides an excellent opportunity to engage in activities and initiatives promoting stormwater awareness and education. By adopting a storm drain, volunteering for local clean-up events, or joining discussions on stormwater management, we can actively contribute to preserving and protecting Wisconsin's waterways.
Remember, stormwater pollution affects us all, and every individual action counts. Let's embrace the responsibility of being stewards of our environment and work together to ensure clean and healthy water resources for future generations. Join us in Wisconsin Stormwater Week and be a part of the movement towards effective stormwater management. Together, we can make a positive impact on our communities and the environment.