LOS ANGELES COUNTY : Inspectors Hired to Stop Water Seepage in Subway
County transit officials have hired full-time inspectors at a cost of $200,000 to $500,000 to supervise installation of water-resistant plastic sheets behind the walls of Metro Red Line subway extensions now under construction.
The move was approved by Rail Construction Corp. engineers in an effort to stop underground water and escaped sewage from oozing into the tunnels and stations.
The subway has been lined with thick sheets of high-density polyethylene to keep water and potentially explosive methane gas out of tunnels and stations. But water leaks are common on most sections completed so far.
RCC engineers suspect that faulty welds at the seams of plastic sheets may contribute to the problem. Until now, only a sample of those welds were inspected. The additional money will be used to hire workers to double-check every seam.