Hundreds of rivers and tributaries criss-cross North America. Major ones often supply fresh water to local residents and some even serve as important commercial routes. The Brazos, the Colorado, the Columbia, the Hudson, and the Mississippi are major waterways, but smaller rivers are equally important to people and animals. Each June marks National Rivers Month, when people are encouraged to participate in river cleanup events throughout the month and even through the year. Various nonprofit organizations organize river cleanups that aim to prevent plastic from entering the world's oceans from rivers. Others help collect trash that otherwise would contaminate rivers and prove harmful to wildlife. River trash is more than an eyesore; it can contaminate drinking water and poison marine life.
