Thursday: Leaves 101
Why is it important to keep leaves out of the storm drains?
As part of our daily Wisconsin Stormwater Week series, today's topic, "Leaves 101," sheds light on the importance of keeping streets leaf-free to prevent stormwater runoff pollution. As the vibrant colors of autumn start to blanket Wisconsin landscapes, it's crucial to understand how leaves can contribute to stormwater pollution and what homeowners can do to mitigate this issue. Let's discover why leaves pose a risk to water quality and learn practical steps to prevent stormwater runoff pollution caused by leaf accumulation.
Join residents from around Wisconsin as we explore Leaves 101!
What is Stormwater Runoff?
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 Should We Keep Streets Leaf-Free?
The accumulation of leaves on streets and in storm drains can have several harmful effects on water quality and aquatic ecosystems. First, when leaves block storm drains, they impede stormwater runoff flow that can create localized street flooding. This excess water can then pick up pollutants such as oil, heavy metals, and bacteria from the streets and carry them directly into our waterways. Second, as leaves break down, they release organic matter and nutrients into the water, including nitrogen and phosphorus. A study from the U.S. Geological Survey conducted in Madison shows leaves are one of the largest sources of phosphorous in urban stormwater. The decomposition of leaves also releases tannins and other organic compounds that can discolor water and negatively impact its quality. When excessive amounts of these nutrients enter our waterways, they can fuel the growth of harmful algae blooms that deplete oxygen levels in the water, leading to "dead zones" where aquatic life struggles to survive.
What Should You Do With Leaves?
Now that you understand how leaves contribute to stormwater pollution, below are a few simple ways you can take proactive measures to prevent them from being part of the stormwater runoff pollution problem. Most importantly, timely removal of leaves from the street can have a positive impact on reducing harmful phosphorous concentrations in stormwater and Wisconsin’s waterways.
Raking or mulching leaves on your property: One of the simplest and most effective ways to prevent stormwater runoff pollution from leaves is to rake or mulch them on your property. Regularly raking fallen leaves and keeping them out of the streets and storm drains, especially before any rain event is critical. Alternatively, mulching leaves with a lawnmower can shred them into smaller pieces that decompose faster and can be left on your lawn as organic matter. Mulching leaves provides valuable nutrients to your soil, promoting a healthier lawn.
Composting leaves for reuse: Composting leaves is an eco-friendly approach that allows you to reuse their organic matter to enrich your garden or yard. By creating a compost pile or using a compost bin, you can collect leaves along with other organic materials like food scraps and yard waste. Over time, the leaves break down into nutrient-rich compost, which can be used as a natural fertilizer for your plants.
Avoiding leaf pile accumulation near storm drains and gutters: Regardless of what you choose to do, it is crucial to avoid piling leaves near storm drains or gutters. These piles can easily be swept away by rain or wind, ending up in the stormwater system. Instead, place the leaves in areas away from drainage pathways. By keeping leaf piles away from storm drains and gutters, you can prevent them from clogging the system and reduce the risk of stormwater pollution.
Did you know? Leaves are the largest source of phosphorous in urban stormwater.
Interested in Learning More?
Join Phil Gaebler (City of Madison) and Christal Campbell (Dane County Land and Water Resources Dept. and the Madison Area Municipal Stormwater Partnership) on Thursday, August 10, 2023 from 12-1 PM, to learn how timely removal of street leaves before the rain can help keep our waters clean. They’ll share information on a recent U.S. Geological Survey study that evaluates how leaf collection and street cleaning can reduce nutrients to local waters and how partners in Dane County used the results to create a community engagement program to keep streets leaf-free before the storm.
Now What?
Understanding the basics of stormwater runoff and pollution is crucial for protecting our water resources and creating a sustainable future.
We can significantly reduce 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!