Fall is one of the most active seasons for stormwater impacts in our community. As leaves drop and outdoor maintenance increases, so does the amount of material that can enter storm drains during rain or snowmelt.
Stormwater does not get treated before it enters local waterways. That means anything left on streets, driveways, lawns, or sidewalks can be carried directly into ditches, streams, lakes, and the Platte River system.
Why Fall Matters for Stormwater
Seasonal yard work increases three key contributors to stormwater pollution:
- Leaves and yard debris
- Fertilizer and lawn chemicals
- Pet waste and organic material
Individually, each may seem small. Across thousands of properties, they become a significant source of nutrients, sediment, and bacteria in local waterways.
Leaves and Yard Waste
Leaves are natural, but urban stormwater systems are not designed to process large volumes of organic debris.
When leaves enter streets or storm drains, they can:
-
- Block inlets and reduce drainage capacity
- Contribute to localized flooding during rain events
- Break down into nutrient-rich organic material that can contribute to algae growth downstream
In Nebraska’s climate, accumulated organic material can persist through winter and continue affecting water quality into spring runoff.
What helps:
-
- Mulch leaves into lawns where appropriate
- Compost or bag yard waste for proper disposal
- Keep streets and storm drains clear of debris
Fertilizer Use in Fall
Fall fertilization can support healthy root development for spring growth. However, timing and application rate matter.
When fertilizer is applied before heavy rain or in excess amounts, nutrients such as nitrogen and phosphorus can be washed off lawns and into stormwater systems.
Once in waterways, these nutrients can contribute to:
-
- Algal blooms
- Reduced oxygen levels in water
- Declines in aquatic habitat quality
What helps:
-
- Apply fertilizer only when needed
- Follow product label instructions carefully
- Avoid application before rain events
- Keep fertilizer off hard surfaces such as driveways and sidewalks
Pet Waste in Fall Runoff
Pet waste is a year-round source of stormwater pollution, but it becomes more mobile in fall and winter storms.
Unlike natural soil-based nutrients, pet waste contains:
-
- High levels of bacteria
- Parasites and pathogens
- Concentrated nutrients that can degrade water quality
In urban areas, where large numbers of pets are concentrated on lawns, in parks, and on trails, pet waste pollution adds up quickly.
Rain and snowmelt can transport waste from lawns, sidewalks, parks, and streets directly into storm drains and waterways.
What helps:
-
- Pick up pet waste regularly
- Dispose of it in the trash
- Keep waste away from drainage areas
The Seasonal Effect
Fall pollution does not stay in fall.
Materials that enter stormwater systems in autumn often:
-
- Remain in waterways through winter
- Resurface during spring snowmelt
- Contribute to seasonal water quality impacts downstream
What happens in one season carries forward into the next.
Related Links:
Why It Matters
Stormwater systems are designed to move water—not filter it.
When leaves, fertilizer, and pet waste enter the system, they move quickly through storm drains, ditches, channels, streams, rivers, and the Platte River watershed.
Across thousands of properties, small actions determine overall water quality.
Reducing stormwater pollution in the fall helps protect:
-
- Local lakes and streams
- Flood capacity in storm systems
- Groundwater-connected waterways
- Long-term watershed health