Categories Menu

Posted on Dec 3, 2015 in Watershed Education |

Street Gutter Demonstration

Street Gutter Demonstration

While falling leaves are a natural part of autumn, improper leaf management techniques can result in degraded water quality in local streams and lakes.

One pound of phosphorus is able to fuel the growth of 500 pounds of algae. Leaves are one source of urban phosphorus loading to our lakes, so it is important that we keep them upstream and out of our waterways.

Recently, GLA staff and Ripon College biology professor, Dr. Bob Wallace, conducted an experiment to better understand what happens when stormwater runoff interacts with fallen leaves that line street gutters.

Three mason jars, a pile of leaves, and a bucket of distilled water later, we were able to investigate the potential affect of the leaves lining our street gutters, ranging from 3 hours to 3 days of contact.

2015-11-12 15.08.10

What did we find?  As stormwater runoff is trapped by accumulated leaves, the combination creates a “loose leaf tea” where phosphorus leaches out and is transferred downstream, even as the leaves stay in place.

2015-11-12 15.27.54In our phosphorus demonstration, more blue hue correlates with higher phosphorus concentrations.  We found that accumulated leaves in contact with stormwater runoff has the ability to leach a significant amount phosphorus in just a matter of hours!

The blue hues of our simple demonstration serve as a reminder to keep leaves out of the street gutter and out of the lake.

Here are some leaf management tips to remember this fall that can make a HUGE difference for Green Lake year-round:

  • AVOID RAKING leaves into the street or gutter, where they can be transported downstream and degrade local streams and rivers.
  • TAKE CARE to keep raked leaves out of the street and on the terrace, located between the road and the sidewalk.
  • REMOVE ANY leaves or yard waste from storm drains, which discharge untreated runoff and can pollute waterways.
  • DO NOT rake leaves into the lake or the stream.

Together, we can make a difference!