Cleaning up a polluted river is hard enough, but when that river crosses an international border, serves a powerful agricultural industry and carries a human cargo of illegal immigrants—then the job becomes even more difficult. That’s the case in California’s Imperial Valley, a $1 billion farming region that borders the state of Baja California, Mexico, and its booming capital city of Mexicali. A small channel known as the New River originates in Mexicali and flows north to California. Raw sewage and industrial waste from Mexicali’s 1 million residents is dumped directly into the river before it crosses the border, making it one of the most polluted waterways in the United States, according to U.S. officials. Although the water quality improves slightly as it flows... [Log in to read more]