Excessive Amounts of Dried Leaves Can Pollute
Leaves left on the ground throughout the autumn season may seem like a mere annoyance to many people -- nature's way of leaving a bit of a mess that takes everyone some time to clean up.
But the Ohio Environmental Protection Agency cautions that if not managed properly, those leaves on the ground or raked into piles can result in water pollution.
In the fall, leaves become a common water contaminant in urban areas where concentrated populations overload nature's breakdown process. Excessive amounts of dried leaves can be a source of pollution if not managed properly because they contain significant amounts of soluble nutrients, including phosphorus.
When heavy loads of dried leaves wash into streams from storm drains and sewers, the nutrients can cause algae blooms that turn the water bright green and cut off oxygen. This often results in fish being killed. A lack of oxygen causes the algae life to eventually die off, making the stream brown and smelly and damaging to the waterway's ecosystems.
For local communities that collect leaves by requiring raking to the curb for collection, ... Ohio EPA suggests checking the municipal requirements about where they can be placed. If allowed, property owners should rake leaves only to a grassy area along the road where runoff water can soak through leaves and into soil. This prevents water from pooling with leaves that wait on streets and curbsides, which allows the decaying nutrients to wash into storm drains.
Storm drains discharge directly into nearby waterways, so unlike sewer lines, these discharges are not treated before entering rivers and streams. Leaves should never be swept or raked directly into storm drains. Avoid using leaf blowers to move leaves and grass clippings onto sidewalks or into streets.