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Fall Leaves and Stormwater: Managing the Season Mindfully

November 12, 2025

By: Stephanie Kozak, Park Interpreter

It’s that time of year in Michigan when we enjoy watching the leaves change colors and feeling the cooler temperatures arrive. As we experience our blustery fall days, the wind encourages the leaves to let go from their branches and drift down onto our lawns and roadways.

As we celebrate the beauty of fall, those same leaves bring hidden challenges for stormwater management.

The same leaves we celebrate in our views, like this oak at Willow Metropark, can become problematic once they fall. Managing leaves can include both leaving them in our yards and gardens for insects and wildlife and removing them from storm drains, culverts, and other avenues for moving water off roads and hard surfaces.

How Leaves Affect Stormwater

Stormwater is the surface water that results from heavy rain or melting snow. This time of year, a mix of rain, sleet, and snow can put major pressure on our drainage systems. Fall often brings heavier rainfall patterns caused by remnants of tropical storms and seasonal weather changes.

When leaves and large organic debris build up on lawns and roads, storm drains and catch basins can easily become clogged. This prevents the system from working properly and increases the risk of flooding.

In many southeast Michigan communities, stormwater runoff that enters storm drains bypasses treatment facilities and flows directly into nearby rivers and lakes. As a result, large amounts of leaves and organic materials are washed into waterways each fall.

Leafy debris, grass clippings, and other organic matter can be carried by rainwater and snow melt and clog drains or end up in our lakes where it decomposes and contributes to low oxygenation levels in the water.

Once in the water, small organisms break down this organic material, consuming oxygen in the process. This decomposition depletes oxygen levels, which can cause low-oxygen conditions throughout the winter months. The result can be a significant die-off of fish and aquatic organisms— often referred to as a fish kill. Often, we don’t see the full impact until spring, when the ice melts and dead fish become visible along the shoreline.

Fall Clean-Up Tips for Better Stormwater Management

Approaching your fall clean-up with stormwater management in mind can help reduce flooding and prevent excess organic material from entering our waterways.

Here are a few things you can do around your home:

  • Check downspouts and drainpipes to make sure they’re draining properly to prevent damage from freezing.
  • Clean out gutters and downspouts to avoid blockages.
  • Disconnect, empty, and clean your rain barrels. Store them upside down in a cool, dry, protected area for winter.
  • Keep stormwater inlets clear. If you have a drain in front of your home, remove debris to allow free water flow.
  • Clean up any leaves accumulating on driveways, sidewalks, and other hard surfaces.
  • Before it rains or snows, clean up pet waste in your yard.
Leaves and other organic matter can clog storm drains in the fall and can cause water to back up and flood. When the same debris wash into our waterways, they can also lead to problems like lowered oxygen due to decomposition.

What to Do with Fall Leaves

Instead of sending your leaves to the curb, put them to good use!

  • Leave them on your lawn: Mowing leaves into your grass can improve soil health and reduce the need for fertilizer in spring. Just don’t leave thick piles that can block oxygen and moisture.
  • Mix leaves into garden beds to enrich the soil for spring.
  • Use leaves as compost material: Save your fall leaves to use as “brown” material in your compost pile next spring to balance out your “greens.” Be sure to secure them from blowing away.  If you’re not composting yet, now’s the perfect time to start!
  • Insulate perennials: Spread leaves over garden beds to protect plants and provide winter habitat for beneficial pollinators.

Bonus Tip: Snow Removal for Stormwater Mindfulness

  • Shovel early and often. The sooner you remove snow, the less salt and sand you’ll need—reducing pollution in waterways.
  • Keep storm drains clear of snow and pile snow away from bodies of water or areas that tend to collect water.
  • Use salt wisely. More salt doesn’t mean faster melting. Follow product instructions carefully, including melt time, and sweep up any leftover deicing material after the snow/ice melts. Remember: salt stops working when temperatures drop below 15°F.

Resources:

https://mfsengineers.com/news/2025/stormwater-management-in-fall-handling-seasonal-leaf-and-rain-challenges

https://www.rettew.com/wp-content/uploads/2018/03/Q4-Fact-Sheet-FINAL-2.pdf

https://content.ces.ncsu.edu/a-gardeners-guide-to-protecting-water-quality

https://www.almanac.com/more-ways-use-fall-leaves-garden

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