A tunnel boring machine is in the process in 2011 of creating a new 12-foot-wide tunnel to replace the original pipe which was laid down in 1913. Its official name is the Sunnydale Auxiliary Sewer Tunnel and it's a $53 million dollar project. The tunnel will go through mud andh serpentinite rock and is about 40 feet below ground level.
This will help the neighborhood's areas that currently flood in rainstorms.
It will also, in theory, provide the infrastructure allow for large new housing development projects.