Few places are more critical to the water supply in California than this immense northern reservoir in the foothills of the Cascade Range.⁠ ⁠ Fed by runoff from 14,163-foot Mount Shasta and other peaks, California’s largest reservoir opened in 1945 as part of the federal Central Valley Project, an elaborate system of man-made dams, pumps and aqueducts that aims to reduce flood risks and deliver water to farms and cities in the heart of the semiarid state.⁠ ⁠ Shasta Lake can hold enough water to meet the needs of six million people and one-third of California’s farmland. It also provides water for salmon and other threatened species and helps keep salt water at bay in the Sacramento-San Joaquin Delta, which serves as a hub for statewide water transfers.⁠ ⁠ Until this century, Shasta successfully did all of that, helping California grow to more than 39 million people and the world’s fifth-largest economy. But a succession of ever-worsening droughts over the past two decades has made inflows into Shasta far less reliable. The current drought is the most severe on record, and Shasta’s water level is now 33% of its capacity.⁠ ⁠ Federal water managers are now administering painful cuts in allotments to Shasta and other Central Valley Project reservoirs, putting at risk farmland which accounts for a critical part of California’s $50 billion-a-year agriculture industry, disrupting supplies to large cities and small towns, and leaving less for fish. ⁠ ⁠ Shasta Dam straddles the Sacramento River, which originates in the Mount Shasta area in the far northern part of the state. ⁠ ⁠ Rain and snow are funneled into the Sacramento and its tributaries, helping to fill a reservoir designed to hold 4.5 million acre-feet. However, recent drought cycles—made worse by climate change, according to scientists—have greatly disrupted the Shasta watershed. Read more at the link in our bio. Photos by @mattblack_blackmatt/@magnumphotos for @wsj.