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New Research Reveals How Critical Forests are to Drinking Water Supply

Posted by Dr. Cynthia West, Acting Deputy Chief, Forest Service Research and Development in Forestry
Oct 04, 2022
Feather River, Middle Fork, on Plumas National Forest in California

Access to high-quality water will be a defining feature of the 21st century. Record heat waves and drought are not only leading to more frequent and intense wildfires but are also putting one of life’s most valuable resources at risk: the water we drink.

A new Forest Service research report describes how extensively public drinking water systems rely on national forests and grasslands.

Water use per person has been declining for decades; however, a variety of factors such as population growth, food production and ecosystem conditions under a changing climate are contributing to overall greater demand for water – especially in certain parts of the country.

In the West, national forests and grasslands supply drinking water to almost 90% of the people served by public water systems. Some western cities, like Aspen, Colorado, and Portland, Oregon, are more than 90% dependent on national forests alone for their drinking water. The story is similar in the eastern U.S., though most of this water is supplied by private forests.

Still, more than a century of research has demonstrated that forested lands provide the cleanest and most stable water supply compared to other lands. Within the lower 48 states, more than 99% of people who rely on public drinking water receive some from forested lands.

This report is the first of its kind to measure how individual national forests and grasslands contribute to surface drinking water supplies while accounting for networks of pipelines and canals that divert water from the source to areas of high need, also known as “inter-basin water transfers.”

The California Aqueduct in the Mojave Desert near Palmdale, California

These inter-basin transfers are incredibly important sources of drinking water, especially in the West, where cities like Los Angeles receive more than two-thirds of their water from forested lands in California and Colorado.

By showing where our drinking water comes from at a fine scale, this report supports USDA’s Wildfire Crisis Strategy, and work supported by the Bipartisan Infrastructure Law and the Inflation Reduction Act. It helps land managers prioritize forests and watersheds for hazardous fuels reduction, watershed management, and restoration treatments that protect people, communities and resources across the country.

A scenic view of Meadow Creek in the Scapegoat Wilderness
Category/Topic: Forestry