Did you know that tree leaves can cause water quality ‘issues’?
Leaves contain various acids which can throw off the water’s pH. Sometimes even the slightest change in pH can have a dramatic effect on the aquatic ecosystem and result in species of plants and/or fish no longer thriving or worse yet, dying off entirely.
Fallen leaves contain nutrients that can contribute to the growth and flourishing of algae blooms in ponds, lakes, rivers, streams, etc. Over the course of their lifetime these blooms can have detrimental effects on the ecosystem such as reducing the oxygen level in the water. Without oxygen in the water other types of aquatic life such as fish and other plants cannot live.
“Where you rake them (leaves) could have a major impact on water quality and the environment,” said Chad Cook, natural resource educator for the University of Wisconsin-Extension.
He said leaves that are raked into the street or roadway could blow away and end up plugging storm sewer drains or, worse yet, polluting Lake Winnebago with nutrients that cause algae blooms and rob oxygen from the water.
Cook said a major concern is phosphorous from leaves, which serves as a fertilizer for plants and algae living in the water.
“What happens is we see algae blooms every year when there’s sunshine and warm weather in the summer,” said Cook, whose office is in the James P. Coughlin Center in Oshkosh. “Algae blooms makes the water green and if it piles up the blooms can decay and smell. As it decays, it can use up the oxygen in the water that could have been used by fish. That’s when you might see dead fish floating in algae.”
He said there are concerns for humans and animals from blue-green algae.
“It’s a type of algae that contains toxins and if those toxins are in a great enough quantity they can impact humans who wade or swim in the water,” Cook said. “A couple of days later they can have a rash.”
He said dogs and other animals that swim in the lake could ingest water with algae.
“Every year in Wisconsin there’s a dog or two who is in the water and dies and one of the likely causes is ingesting blue-green water from an algae bloom,” Cook said.
He said leaves can also plug up storm sewer drains. Clogged drains, he said, can lead to street flooding. ( source )
It never ceases to amaze us how so many simple things such as the improper disposal of leaves can have an adverse effects on the environment.