For many communities in the West, the water that flows out of kitchen faucets and bathroom showerheads starts high up in the mountains, as snowpack tucked under canopies of spruce and pine trees.
This summer’s record-breaking wildfires have reduced some of those headwater forests to burnt trees and heaps of ash. In high alpine ecosystems, climate change has tipped the scales toward drier forests, lessened snowpack, hotter summers and extended fire seasons.
Wildfires don’t just cause problems while they’re burning. For municipal drinking water systems, fires are felt for years after they’re snuffed out.
Few places in the West know that as well as Fort Collins, Colorado. Until eight years ago, one of the city’s of main water sources, the Poudre River, was nearly pristine. All year round, it tumbled out of the Rocky Mountains and into the city’s treatment plant for use by 135,000 people.
“We had been privileged and in some ways probably took for granted that these watersheds were providing us consistently clean, clear water, all the time,” said Jill Oropeza, the city’s water quality manager.
On a warm, breezy fall morning, Oropeza stood along the river in its canyon northwest of the city, downstream from where the High Park Fire burned more than 87,000 acres in 2012.
“That was the first time for many of us working there that we had to grapple with the fact that our watersheds are under pressure,” Oropeza said.
In the year after the fire, the river would turn black during heavy rains. Mudslides of ash and scorched soil spilled into the water. Signs along the river, and Highway 14, warned drivers to keep an eye out for slides large enough to sweep cars into the river.
Before utility workers could turn off the city’s drinking water intake on the river, that muddy, ashy water filled and clogged pipes leading to the treatment plant.
“We ended up with a lot of sediment in our pipelines that was difficult to remove,” Oropeza said.
Even if workers managed to move the water through the full treatment process,…