Combing through tens of thousands of river images by hand, LCLUC PI David Lutz and team pinpointed where sediment loads begin to rise along each watercourse. They cross-checked those locations with high-resolution imagery from private satellite companies and scoured news and social media for any clues to the cause of the increased muddiness. Some was due to oil palm plantations, but mining was by far the dominant cause. In all, 381 sites showed a surge in muddiness because of mining. The survey grew out of work by Bowdoin College geomorphologist Evan Dethier in the Peruvian Amazon.