Large Sewage Pipe Replacement Moved Up

A long stretch of large pipeline has been sitting on the side of the road behind Marin General Hospital and near Creek Park as sanitary district emergency repair crews work overtime to replace the Kentfield Force Main ahead of schedule.

The Kentfield Force Main, a large sewage main that serves nearly 60 percent of the district, was scheduled to be replaced in the fall of next year. But, after a crack was discovered in the Techite pipe, the Ross Valley Sanitary District board voted to move ahead with the replacement a year before originally scheduled.

Crews have been working around the clock to get the new pipeline in place. Roads near Marin General are partially-blocked and the walking path along the Corte Madera Creek behind College of Marin is closed until the replacement is complete.

A replacement process is being used that essentially pulls the new pipe into place through existing pipe. This allows most of the work to be done underground and eliminates the need for trenches to be dug, minimizing disruption for neighbors.

Techite pipe was widely used in the 1970s (the Kentfield Force Main was installed in 1972) and was considered state-of-the-art, only for the pipe material to begin failing years later. Two other failings in the force main have been repaired before this most-recent crack was discovered, including an emergency fix on South Eliseo Drive about six weeks ago. 

"In light of the second Techite failure this past November on Eliseo Drive, it is too risky for us to just repair the third failure and wait until next fall to finish the job," said Brett Richards, General Manager of Ross Valley Sanitary District (RVSD). 

Richards said that with the heavy rains in the Ross Valley, the pipes can carry up to 50 million gallons in a day. Because of that, the board decided it was important to move the pipe replacements up a year.

The emergency work, which could take up to eight weeks, will replace the remaining section of the Techite pipe under the berm along the Corte Madera Creek. Approximately 30 percent of the overall force main will remain to be completed on schedule next fall. The project is one of two multi-million dollar pipe replacements the district is undergoing.