The concrete lining is thick, reducing the finished tunnel diameter to .
The pit, however, was still intact, except that its concrete lining was badly cracked.
They say the 1944 international treaty on the distribution of water from the Colorado River, which feeds the canal, does not prohibit the concrete lining.
This concrete lining was first used in the Devil's Courthouse Tunnel.
That's not going to be safe again unless we firm up this bank with a concrete lining, and lift the path.
These waterways have been drastically altered since the late 19th century by the means of concrete lining.
The tunnel was renovated during 1999-2000, replacing the brick lining with a concrete lining.
Temescal Creek near the mouth area is channelized with concrete linings.
The barrage is an earth dam with asphaltic concrete lining.
In the 1970s, a concrete lining was applied to the western half of the tunnel to prevent rockfalls inside.