Save the California Delta Alliance (STCDA)

Here’s a great blog by Deirdre at California Water Research about the issues being ignored or hidden with the tunnel construction. “WaterFix: Tunneling risks and tunnel construction contracts”

Summary:
“Whether there is one Delta tunnel or two, the construction of a large diameter tunnel in Delta soils consisting of sedimentary layers of peat, sand, silt, and clay is a significant engineering challenge.

There was a large sinkhole created by “Big Bertha” during the Seattle Highway 99 tunnel construction which “shows the problems that can be created by “loss of ground” when tunneling in sedimentary deposits. Even when there is no “loss of ground” there can still be significant settlement on the surface. Washington Governor Jay Inslee halted the tunnel boring on January 14, 2016, citing concerns over public safety.”

“The current alignment of the WaterFix main tunnels passes under Delta island levees, State Route 4, State Route 12, the BNSF railroad tracks used by Amtrak, the Mokelumne aqueduct, and natural gas and other product and services pipelines. These are all critical infrastructure in the Delta. But measures to protect this infrastructure from tunneling impacts were not identified in the WaterFix environmental documents.”

Read all the details at: “WaterFix: Tunneling risks and tunnel construction contracts”