Nutrient Pollution in Tuscarora Creek Likely Due to Lawn Fertilizer

Did you know that lawn fertilizers can impact the health of our local streams? When it rains, excess fertilizer applied to lawns is picked up by stormwater and carried down storm drains that lead directly to local waterways.

The amount of nutrients introduced to a stream from lawn fertilizers and other sources is much more than a stream can naturally manage. The same nutrients that encourage grass to grow also cause algae to grow in water. Algae spikes can harm water quality and decrease the oxygen levels in water that fish and benthic macroinvertebrates need to survive.

On April 8, our Stream Team surveyed of a section of Tuscarora Creek that crosses the W&OD Trail in Leesburg. The survey revealed unacceptable ecological conditions (with a score of 6 out of 12) and an overabundance of two specific types of pollution-tolerant macros: midge and black fly larvae. View data for monitoring site.

When black fly larvae dominate a stream monitoring sample, this can indicate moderate organic or nutrient pollution in the stream – and a likely source of this pollution in the spring is lawn fertilizer.

If you use fertilizer on your lawn, here are a few things you can consider doing to reduce the burden on our local streams, like Tuscarora Creek.

• Read the instructions on the fertilizer package and apply the right amount of product to your grass at the right time.
• Sweep excess fertilizer off hard surfaces to decrease the amount of fertilizer ending up in stormwater runoff.
• Use a mulching mower to help naturally fertilize lawns. Mulching mowers leave behind shredded grass clippings that act as compost to fertilize your lawn without adding chemicals.
• Consider landscaping with native plants, which will reduce the amount of grass on your property. This will require less fertilizer, watering and mowing. Native plants also help filter out pollutants in runoff, in addition to providing habitat for birds and butterflies.