How much of our water supply comes from national forests?

Forests and grasslands provide some of the cleanest, most reliable water in the country. Many communities, especially in the West, rely on water from National Forest System lands for drinking and other uses. Continued management is required to keep these ecosystems and watersheds healthy and resilient to potential disturbance events like wildfires. But in a world with limited budgets, it can be difficult to justify long-term planning costs without knowing the value of present and future water benefits. Therefore, scientists have created methods to calculate the economic value of the water from forests and the economic returns from improvements in forest health and water quality.

Photo Credit

Forest Service figure by Joey Blumberg

Across the U.S., national forests reduce erosion and protect water quality, which saves an estimated $47 billion in costs associated with water quality violations, dredging, and water treatment.

They found that each year, surface water flowing from national forests and grasslands contributes 5.2 trillion gallons of public water supply to communities throughout the U.S. This water is valued at $47 billion annually, an estimation based on avoided costs from Safe Drinking Water Act violations, dredging, and water treatment thanks to forest functions that reduce erosion and protect water quality. Populations in the Rocky Mountain Region (Forest Service Region 2) lead the nation in terms of how much of their water is sourced from national forests. Of their public supply from surface water sources, 25 percent comes from national forests, accounting for 29 percent of the total value. California, where much of the water originates on national forests and where water prices are relatively higher, spends the most on water from national forests lands, at $13 billion annually. Of the total water supplied by national forests, most comes from California, the Rocky Mountains, and the Southeast (Forest Service Regions 2, 5, and 8): these areas provide 3.8 trillion gallons annually to U.S. households, or 72 percent of total surface water provided by Forest Service lands.

This work is helping managers communicate the value of their forests and more effectively prioritize restoration efforts in high-value watersheds. It also contributes to the Resources Planning Act (RPA) Assessment and efforts to measure the economic return of fuels treatments. 

Photo Credit

USDA photo by Lance Cheung