Tulsa City Councilors Take Tour Of 'Tiawah Tunnel' Water Pipeline

Wednesday, February 11th 2015, 5:58 pm
By: Emory Bryan

News On 6 went underground for a look at something never seen on television, the tunnel that delivers water to Tulsa from Lake Spavinaw.

It's one of the key pieces of Tulsa's water supply. It's called the "Tiawah Tunnel" and on Wednesday while it was down for maintenance, we had a chance to walk through it.

The city staff that maintains the tunnel tells me it takes about a day for water to flow from Spavinaw down to the Mohawk treatment plant.

Two of Tulsa's city councilors suited up - and booted up - to get the underground tour of a critical link in Tulsa's water supply.

The Tiawah Tunnel is an almost two-mile long water line blasted out of limestone in the 1920s.

The tunnel is 84 inches in diameter, big enough for two people to walk side by side, and for decades carried all the water Tulsa needed.

It's drained for maintenance every 3 years or so, giving city councilors a rare chance to walk the length of it.

"This gives us a chance to learn...the walk a mile in their shoes," said City Councilor Jeannie Cue.

The tunnel is almost perfectly straight, and slopes just enough so gravity does most of the work moving the water.

The maintenance checks give the city the confidence that this almost century-old pipeline will last a while longer.

While the tunnel is drained, engineers come through and look for problems like cracks on the ceiling. They'll go through every inch and mark things like holes that could create a leak in the tunnel.

Crew leader Chad Millburn said, "So that's what they're checking is how far does the void go and is there bedrock behind it."

Workers run a scanner over the walls of the tunnel to look for thin spots. The process is slow, but the tunnel was so well built they rarely find significant issues.

"It's through rock, so this is basically a lining," said crew leader Andy Herring.

It helps that solid rock surrounds the concrete tunnel and it's well protected, 100 feet down. For councilors, the trip was remarkable, the history almost unbelievable.

Councilor David Patrick said, "Almost 100 years old and we're still using it today and we're still using the oldest infrastructure in the City of Tulsa and it's still in really good shape."

The city staff that maintains the tunnel says it takes about a day for water to flow from Spavinaw down to the Mohawk treatment plant. While this tunnel is down, Tulsa is getting water from Lake Oologah.