Annually, more than 50% of phosphorus in our surface waters comes from leaves in the street according to a 2016 study by the United States Geological Survey, making leaves one of the largest sources of urban phosphorus pollution.
As rain falls and flows through leaves, phosphorus leaches out much like a tea bag in water. This “leaf tea” flows through our storm sewer system to the North Platte River.
Too much phosphorus causes large and potentially dangerous algae blooms that can block sunlight for aquatic plants, clog the gills of fish, reduce levels of dissolved oxygen, and produce toxins that are harmful if ingested. It only takes one pound of phosphorus to produce 500 pounds of algae (Vallentyne 1974).
Removing leaves from the street before it rains can reduce the amount of phosphorus in urban stormwater by 80% compared to no leaf removal (USGS 2016).
Protect your waters, by sweeping leaves back onto the lawn or garden as mulch, composting them, or putting them into the City’s yardwaste container.
Precautionary tips since the leaves are falling …
1. Check and clear the gutters for leaves, if you haven’t already. Leaves can clog both street and building gutters, quickly causing flooding and water damage.
2. Wet leaves can be a slipping or fall hazard on sidewalks and curbs, so move leaves back to the yard or garden from the gutter.
3. Piles of leaves are fun to jump in, but also great habitat for beetles, mites, and other insects – and the animals that feed on them. So look before leaping into the pile.
Photo © Janeh15 – Dreamstime.com