The Importance of Water in the Sierra
- May 11, 2019 -

In celebration of the Cal Middle School students joining us on Donner Summit this May for a program on water science, we were inspired to share some of our resources. Here’s a great explanation of the importance of water in the Sierra from the Water Education Foundation. We think it’s of the utmost importance for the students we teach, and for our friends, followers, and family, to understand the importance of these vital resources in the natural world.

Stretching along the eastern edge of the state, the Sierra Nevada region incorporates more than 25 percent of California’s land area and forms one of the world’s most diverse watersheds.

The Sierra Nevada is 450 miles long and 40 to 50 miles wide and includes granite cliffs, lush forests and alpine meadows on the westside, and stark desert landscapes at the base of the eastside. Its habitats support 66 percent of the bird and mammal species and about 50 percent of the reptile and amphibian species found in California including bighorn sheep, mule deer, black bear and mountain lions, hawks, eagles, and trout.

On average, 60 percent of California’s total annual precipitation – in the form of rain and snow – falls in the Sierra Nevada and a portion of the southern Cascades.

Snowmelt from the Sierra’s provides water for irrigation for farms that produce half of the nation’s fruit, nuts and vegetables, and also is a vital source for dairies, which have made California the largest milk producer in the country.

In addition, Sierra snowmelt provides drinking water to Sierra Nevada residents and a portion of drinking water to 23 million people living in cities stretching from the Bay Area to Southern California.

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Sierra Nevada Water Cycle

The Sierra Nevada watershed provides much of California’s water because of its mountains, which “catch” eastern-moving clouds fattened by the Pacific before they reach Nevada.

In the Sierras, precipitation falls and accumulates during the winter months in higher elevations as snow. The snowpack acts as a natural reservoir that holds water until temperatures rise in late spring. In spring, the snowpack melts to provide significant runoff on the Sierra Nevada’s west slope and, to a lesser extent, on the Sierra Nevada’s eastern slopes.

The rain and snowmelt captured in the upper elevations flow to fill rivers and reservoirs and recharge groundwater basins.

Sierra snowmelt in spring typically contributes half of the total annual runoff from the region. After the high risks of floods have passed during spring, water is allowed to fill the reservoirs. By late summer, when natural river flows are at very low levels, water releases from the reservoirs provide much of the downstream water supply.

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At Headwaters, Many of the students we work with, especially those from Sacramento or Bay Area schools, don’t have plentiful opportunities to visit the Sierra, but this is the place their water comes from! By engaging students in science learning opportunities, we also encourage them to think from the source, asking questions like: where do the resources I use daily actually originate? We hope sharing this information encouraged curiosity in you, too!

*This post was authored by the Water Education Foundation