Sierra Club —
Friant Dam, just outside Fresno, California, is a sprawling structure, 319 feet tall and two-thirds of a mile across. It’s not the tallest or the longest dam in the United States, but measured by the impact on the river that it constrains, it looms larger than most.
Constructed just after the Great Depression, Friant Dam was devised to control the San Joaquin River, California’s second-longest waterway. The river’s raucous flow, fed by snowmelt from the Sierra Nevada, was corralled in a 4,900-acre reservoir called Millerton Lake (named for the small town it drowned). From there, it was divvied up and shunted into a vast network of canals to supply water for millions of acres of farmland and the Central Valley’s growing cities. For decades, one 60-mile section—beginning 38 miles downstream of Friant Dam and stretching to the San Joaquin’s confluence with the Merced River—ran dry. Parts of the river where water still flowed were blighted with pesticides and fertilizer, creating massive algal blooms and dead zones.
The intensive engineering of the river exacted a huge toll on its native ecosystems. No species suffered more than the Chinook salmon, whose epic migration from the Pacific Ocean to its spawning grounds in the High Sierra was cut short by numerous choke points, not the least of which was Friant’s impenetrable barrier of concrete.