Reduce Your N Footprint

Wastewater is the biggest culprit in Cape Cod’s water quality woes, but it’s not the only one. We sometimes forget that there are other sources of nitrogen pollution, and some of them can be addressed through simple lifestyle changes — and, unlike with wastewater treatment, at no cost.


Depending on where you live on Cape Cod, wastewater makes up 50-85% of the nitrogen entering estuaries. This percentage can vary depending on how much agriculture, open space and wetlands there are in your watershed, and how dense the development is. That leaves a sizeable amount of nitrogen that we may be able to reduce without the expense of sewering or other wastewater treatment options.

Think of that “silent” part of the total nitrogen load as having two parts: the source, and then the path it follows once it’s in the watershed. Communities and individuals have some control over both the sources and the path.

20150805_141153First, the sources: these include fertilizer used on lawns, golf courses, and agriculture; and air pollution from cars, factories, and other fossil fuel burning settling on the land and water. We can minimize the sources by reducing or eliminating fertilizer use on our own yards and encouraging others, including golf courses and landscaping businesses, to do the same. We can abandon chemically‐maintained greenscapes and make “Cape Cod lawns” the standard of beauty, since they reflect our concern for the health of our bays. We can reduce our use of fossil fuels by walking, biking and busing more and driving less, and by conserving energy at home and at work. Eating local, sustainably grown food recycles the nitrogen already in the watershed, rather than importing more in the form of food, which then gets added to the wastestream (and requires energy to transport).

Second, the path: once that nitrogen enters the watershed from any source, it can be washed by rain over hard surfaces directly into the bay or other water bodies, or it can be intercepted and taken up or turned into harmless nitrogen gas by vegetation and wetlands as it flows across the land or through the groundwater. Which path it follows can make a big difference in how much of the nitrogen actually enters the bay. Naturally vegetated tracts of land, particularly forests and salt marshes, remove much of the atmospheric nitrogen that falls on them. Support for land trusts and other conservation organizations helps ensure these lands remain in their natural state and continue to act as filters for our water. Lawns and golf courses remove less N than forests and marshes, and are often fertilized, exacerbating the N problem. So converting our yards from lawn to native plantings can provide a double benefit. Roads and other hard surfaces don’t remove any nitrogen, and in fact act as conduits for run-off fertilizer, along with other pollutants like motor oil. It’s important that stormwater be allowed to percolate through vegetation and soil to help filter it, rather than flowing directly into streams, ponds, marshes, and bays.

greenfootprintWe can all take steps to reduce our N footprints 
Conserve energy in our homes and workplaces.
Bike, walk, ride public transit whenever possible. Even one or two days a week helps!
Replace lawns and paved areas in yards with native shrubs and trees.
Use Falmouth Friendly Lawn techniques for yard care. Avoid the use of chemical fertilizers and pesticides.
Support the purchase and preservation of conservation land — Join the 300 Committee!
Choose food grown on sustainable farms where carbon and nitrogen inputs are paid attention to and choose locally grown food when possible, reducing both your carbon and nitrogen footprint.
Minimize food waste. The more food we waste, the more food must be grown, the bigger nitrogen problem we have.