The excavation of the downstream portal is complete, and crews are now working on final touches. Two thrust blocks were poured to support the Chimney Hollow Conduit, which will be placed in the tunnel at a later date. By early May, crews will work on a lining system that will run from the downstream portal entrance back to the valve chamber.  

In the valve chamber, installation of a smoothing grouting is in progress that will enable a waterproof membrane to be installed. Any seepage that goes through the concrete will be caught by the membrane, like a rain jacket, to protect all of the valve house equipment.     

Excavation of the tunnel’s upstream portal started the last week of March. Unlike the downstream portion, which was drill and blast, crews will excavate this portion with a road header. The upstream portion of the tunnel will be 11 feet in diameter horseshoe shape. It is anticipated that crews will be able to excavate 15 feet per day with the road header and will be done excavating in four months.