Rivers were key to the development of human settlement. Camps became villages, villages became towns and towns became cities, all because of the functions and resources rivers provide. However, as we’ve developed, humans’ environmental impact on rivers has become increasingly detrimental.

Stormwater drains often filter out into these essential waterways, carrying oils or trash from the streets. Exhaust fumes from cars put carbon and nitrogen compounds into the air, which can eventually settle into rivers. People using the river for recreational or work purposes — including boating, canoeing and swimming — can also leave fuel and trash, disrupting the habitat of native species.

Although we can’t prevent all of these impacts, being more aware of our potential impacts on these key waterways may help us reduce the damage. In Washington, D.C., keeping the Potomac River clean starts with small things, like picking up litter and cutting down on plastic waste. Local cleanups and community efforts can make a big difference in protecting our rivers.