Every year since the 1850s, when settlers began to build roads and redistribute the Southwest’s desert soils, heavy winds have blown a fine coat of dust on the snow pack in the Rocky Mountains, which works to reduce the flow of the Colorado River by about five percent each year, according to a new University of Colorado study (via the Fort Collins Coloradoan). Factor in climate change, and the river’s flow could be reduced by as much as 25 percent in about four decades, a situation that could affect the availability of water everywhere, including Fort Collins.

The Colorado’s water is already under strain due to delivery rights much further downstream. The New York Times reports that as the Southwest’s drought continues beyond a decade, the distribution of the river’s water increasingly faces the possibility of being reordered. That’s because Lake Mead, a source of water for agriculture, laws, and golf courses from Las Vegas to Los Angeles, is on the brink of disturbingly low levels. The shortage at the lake could trigger conservation efforts that will leave lawns crispy everywhere but California, which has “first call” on flows in that part of the river basin.