US City Starts Earthquake-Proof Water Pipeline Project

The US city of San Francisco has started the construction of a five-mile tunnel under San Francisco Bay to supply water to Bay Area communities.

The $347m tunnel project is part of the $4.6bn water project to overhaul the Hetch Hetchy water system, which was designed to secure water supply in the event of major disasters, such as earthquakes.

Under the project, two decaying pipelines built during the 1920s and 1930s will be replaced with new seismic resistant pipelines.

The project also includes laying up of 3ft-thick watertight walls and a 12ft-thick concrete floor slab, which will be located at depths of up to 100ft.

The project is expected to be completed by 2015, according to upi.com.