San Francisco officials are celebrating the ceremonial launch of a multibillion plan to upgrade the system that delivers water from the Hetch Hetchy Reservoir near Yosemite to the Bay Area.
Mayor Willie Brown broke ground yesterday on the first of dozens of projects that will make the waterworks more earthquake resistant.
Last year, San Francisco voters approved $1.6 billion worth of bonds for the improvements.
The system of aqueducts and tunnels was built in the early 1900s and has fallen into disrepair. If it breaks, the flow of water to millions of people in the Bay Area could be halted for up to two months.