Wednesday Top of the Scroll: Celebration and concern – Hetch Hetchy reservoir turns 100, but climate change complicates its future
San Francisco Mayor London Breed and a gaggle of water officials gathered in the northwest corner of Yosemite National Park on Tuesday to celebrate the centennial of the creation of the Hetch Hetchy Reservoir and the O’Shaughnessy Dam. … The water system, San Francisco’s main water source, provided a stable supply of pristine Sierra Nevada snowmelt for city residents through most of the 20th century. But as human-caused climate change worsens, some water experts say the stability of San Francisco’s mountain tap is losing its surety for the 21st century and beyond. “I no longer think it will be a reliable water system,” said Samuel Sandoval Solis, an expert in water management at UC Davis. … The water passes over three faultlines and is used for about 85% of the water needs for 2.7 million people in San Francisco and parts of Santa Clara, San Mateo and Alameda counties.