SAN FRANCISCO - The Sierra snowpack is vanishing quickly. Compared to the historical snowpack for this time of year, the May 2021 survey shows that we are only 2 to 5 percent of normal.
In Yosemite National Park, the Hetch Hetchy reservoir relies on the annual snowmelt to stay full. The reservoir provides water to a large portion of the Bay Area through a 160 mile delivery system.
About 2.8 million residents in the Bay Area depend on water from the Hetch Hetchy. This includes San Francisco, San Mateo, Santa Clara and Alameda Counties.
For a reservoir that relies on snowpack, the Hetch Hetchy reservoir is actually in pretty good shape in terms of water supply.
Currently, the reservoir is holding 93 billion gallons and continues to rise. The outlook calls for water storage to grow to 117 billion gallons, which is full capacity.
During a normal year, snowmelt into the reservoir is enough to fill it completely three times. While that is not the case this year, supply will meet the demand for Hetch Hetchy customers.
Right now, there are calls for voluntary reductions for the 1,600 irrigation customers in San Francisco. While this mainly affects parks and golf courses, there could be tighter restrictions if the drought continues next year.
KTVU Meteorologist Mark Tamayo visited the Hetch Hetchy reservoir during the extreme drought of 2015. The reservoir was holding 80 billion gallons at the time, far lower than current levels.