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Transcript for Challenge at Glen Canyon, segment 06 of 11
And there would be a rush. The rain and snow that had caused the high river flows of nineteen eighty-three showed no signs of abating. In fact, as nineteen eighty-four approached, frequent heavy fall rains and early winter snows swept into the distant headwater mountains. With no time to waste, the contractor began an access route, a one hundred eighty foot long tunnel cut into the side of the left spillway.
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A temporary roadway was placed across the power plant transformer deck and a similar access tunnel was cut into the damaged right spillway. With the standing water finally pumped out, the spillway disclosed an amazing array of rock rubble that had been gouged from the tunnel floor, including this huge boulder that had been broken loose and lifted out by tons of falling water.
Most astonishing of all was the big hole at the elbow section found to be thirty-two feet deep, forty feet wide, and one hundred fifty feet long. Within a few days, concrete was flowing into the hole. Twenty-five hundred cubic yards were needed to fill it.
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Broken, eroded concrete was removed by drilling and blasting to reshape the tunnel to make it ready for a new three foot thick concrete lining. Dangerous work, but performed carefully by drilling ahead and under the old concrete.
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And to keep the sandstone in place, rock bolts several feet long were tightened into place.
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As the winter came on, a curtain was drawn over the spillway portal to keep out the cold, desert winds, but in the mountains, the snow continued to deepen. It was beginning to appear that the Glen Canyon spillways might indeed be needed in nineteen eighty-four.
Lake Powell had been drawn down twenty-seven vertical feet which represented an immense amount of available storage. But was it enough? A continual problem at the Glen Canyon spillway repair, as well as a major source of discomfort to the workers, was the water that seeped into the tunnel and fell like rain or like a waterfall.
Much of the water could be collected in pipes and directed to pumping stations.
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Work then proceeded on the network of reinforcing steel bars and a placement of the new concrete lining.
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