Rivers are forces of nature, but over time, humans have learned to harness their power and change their course — often for the worse. Here are four stories on how humans have changed local and regional river systems, and the disastrous and sometimes deadly consequences.

1. “Use It or Lose It.” (Abrahm Lustgarten, ProPublica, June 2015)

“First in time, first in line.” In a piece from the Killing the Colorado series, which offers an in-depth look at the Colorado River, Lustgarten explores the effects of a water law that encourages ranchers to use as much water as possible, even during a drought, and the principle that those who arrived first in the West should have the most senior water rights.

2. “River of Death.” (Steve Fisher, Fusion, 2015)

In 2008, a boy living in the El Salto industrial area of Jalisco, Mexico, fell into the Santiago River. Eighteen days later, he died from arsenic poisoning. There are 300 companies along the river, with factories dumping chrome, lead, zinc, mercury, toluene, phosphorus, cyanide, and other chemicals into it. Fisher finds no evidence that companies are held accountable, while the Mexican government is unwilling to enforce environmental standards.

3. “The Ganges: Holy, Deadly River.” (Victor Mallet, FT Magazine, February 2015)

“Her waters are pure, medicinal even, and she is the responsibility of the gods, not of humans.” In a tour of India’s Ganges River, Mallet finds it so toxic — from sewage to industrial waste to charred human remains — that it’s hard to stomach the belief that the river is “so sacred that it’s considered beyond harm.”

4. “The San Jacinto River Waste Pits Unleashed Toxins into the River and, Residents Say, Their Bodies.” (Susan Du, Houston Press, November 2014)

In the Highlands area of Texas, members of the Bonta family — and their ranch’s animals — are sick: John has a rare blood cancer, Jackie is diagnosed with endometriosis, and the dog dies of a liver tumor. Over time, a dump site, created by paper and waste companies nearly half a century ago, has released carcinogens into the nearby San Jacinto River. The Bontas have fled, but others in the area, including the Vietnamese fishermen who work in the San Jacinto River and Galveston Bay, continue to deal with the damage.

Cheri has been an editor at Longreads since 2014. She's currently based in the San Francisco Bay Area.