Population growth and poor agricultural practices are the main culprits in a deterioration of the Potomac River’s health, according to a recent environmental study. The Potomac Conservancy released its yearly State of the Nation’s River report last Thursday, and gave the waterway a D grade, down from a D+ in its first report in 2007.
As cities surrounding Washington have grown over the past five years, development of new neighborhoods has destroyed much of the forest that usually contains and filters rainwater flowing into the Potomac. Now with the addition of many non-absorbent surfaces, such as roofs and parking lots, in cities, more polluted water is flowing into the watershed than ever.
At the same time, a growing number of farms around the river valley have led to runoff contaminated with nutrients from animal feed and waste. The decay of these nutrients in the water depletes oxygen, resulting in fish kills and “dead zones,” where there is not enough water to sustain marine life, in the river and Chesapeake Bay. The Potomac is also often unsafe for swimming after summer rainstorms, when overburdened city sewer systems spill human waste into the river, a problem that only worsens with population increase.
The poultry industry presents a particular difficulty. Chickens are big business in Northwest Virginia and Maryland, but their waste is especially harmful to the river. It is rich in oxygen-depleting nitrogen and phosphorous, along with a host of other harmful bacteria like E. Coli. Even so, there are few rules governing the handling of waste by big farms, and the policies are, according to the report, “vague.” As levels of runoff have increased, the uptick in farming activity and waste has created a particularly tough environmental situation for the Potomac.