0.000 0.708 BEN: .. Okay folks, 0.708 2.142 we're coming to a short stairway, 2.142 2.970 use the handrails, 2.970 4.087 and be careful please. 4.087 94.800 >ENV: ((FOOTSTEPS_AND_AMBIENT_CROWD_NOISE)) 94.800 95.277 BEN: Okay folks, 95.277 96.340 let's find out where we are. 96.340 98.341 ... We got on the elevator right here, 98.341 101.019 .. came down and stood on the balcony overlooking the power plant, 101.019 102.583 ... (H) down that stairway, 102.583 104.621 out on the power plant ramp about that far, 104.621 106.508 (H) then right at that yellow line. 106.508 110.367 (H) And you're now standing over the second-largest water pipe in the world, 110.367 112.169 (H) and it's called a penstock. 112.169 113.829 ... More about that a little bit later. 113.829 115.576 .. (H) The Colorado River, 115.576 116.871 flows in this direction. 116.871 118.334 (H) In order to build a dam here, 118.334 119.995 the very first thing they had to do=, 119.995 121.498 (H) was to get rid of that river. 121.498 124.062 .. (H) So they came up here above where the dam was to be built, 124.062 125.615 (H) and drilled and blasted out, 125.615 127.057 four diversion tunnels. 127.057 128.712 (H) Two on either si=de, 128.712 130.008 (H) into the canyon wall, 130.008 131.566 around where the dam was to be built, 131.566 133.106 (H) out in the river down below. 133.106 137.059 (H) Each one of these tunnels were drilled and blasted out at fifty-six feet in diameter, 137.059 139.037 (H) and then lined with three feet of concrete. 139.037 141.740 .. (H) You're now standing in one of those old diversion tunnels. 141.740 143.063 ... (H) They then came up here, 143.063 145.367 and they built a cofferdam about a hundred feet high, 145.367 148.081 (H) to force this river into these diversion tunnels. 148.081 149.225 (H) Came back down here, 149.225 150.932 built the other part of that cofferda=m, 150.932 152.823 (H) about sixty-five feet high=, 152.823 155.578 (H) to keep this water from backing into the work area. 155.578 157.284 (H) They now had from he=re, 157.284 159.045 (H) to here where they could build a dam. 159.045 161.085 .. (H) They pumped the water out of this area, 161.085 164.614 (H) and excavated down another hundred and thirty-five feet to bedrock. 164.614 165.550 .. (H) Okay folks, 165.550 166.210 if you will please, 166.210 168.142 take a look at this picture taken during construction, 168.142 170.764 .. (H) looks like a series of boxes or blocks, 170.764 172.160 stacked one on top of the other, 172.160 174.694 .. (H) and those are wooden concrete fo=rms. 174.694 177.381 (H) Each one of those forms are exactly five feet high, 177.381 179.659 (H) but they did vary in area somewhat, 179.659 182.756 (H) because they did not build the dam right straight across the river, 182.756 184.641 (H) from canyon wall to canyon wa=ll, 184.641 186.624 (H) they built it in the form of an arc. 186.624 189.457 ... And it's called an arch .. gravity design dam. 189.457 190.965 (H) Where the force of the water, 190.965 193.414 coming down the Colorado River hits the face of the dam, 193.414 197.085 (H) and tends to try to drive these wingtips further into the canyon wa=ll. 197.085 199.179 .. (H) It's a very strong design. 199.179 202.265 ... They did build two concrete mixing plants here, 202.265 204.764 (H) they did pour concrete for twenty-four hours a day, 204.764 205.808 seven days a week, 205.808 208.020 (H) three hundred and sixty-five days a year. 208.020 209.282 (H) For two years, 209.282 211.010 .. less ... six days. 211.010 215.743 (H) Now every bit of that concrete came down in individual eight-cubic-yard bucketloads. 215.743 218.384 (H) Eight cubic yards of concrete into one of these forms, 218.384 221.163 (H) the smallest of which is twenty-two by twenty-five feet, 221.163 224.279 (H) only filled that form up about three or four inches deep. 224.279 226.543 .. (H) So there goes that story you may have hea=rd, 226.543 228.852 (H) that there are workers buried in the concrete here. 228.852 230.385 .. Couldn't possibly happen. 230.385 233.313 .. (H) But what they did bury in that freshly poured concrete, 233.313 235.110 (H) was one-inch steel water pipe. 235.110 237.513 .. (H) They came down here in this lower cofferda=m, 237.513 239.354 (H)= and they built an i=ce plant. 239.354 242.284 .. Capable of making a thousand tons of ice a day. 242.284 243.653 (H) They used that ice, 243.653 244.716 to chill the water, 244.716 247.705 (H) that they forced through that pipe in this newly placed concrete. 247.705 249.241 .. (H) As concrete ha=rdens, 249.241 250.501 or cures as we call it, 250.501 251.867 (H) it produces heat. 251.867 254.000 ... The more you can control that heat, 254.000 256.033 (H) the better job of curing you're going to get. 256.033 257.910 .. (H) So they used the chilled water method, 257.910 259.011 of taking that cold water, 259.011 261.695 (H) forcing it through that pipe in that newly placed concrete, 261.695 263.338 (H) picking up some of that heat, 263.338 265.191 (H) then carrying that heat out and away. 265.191 268.036 .. (H) They felt if they did not use a method such as this, 268.036 271.600 .. that it would've taken approximately (H) one hundred and fifty years, 271.600 274.952 for the concrete .. in the interior part of the dam (H) to cool down. 274.952 276.454 .. (H) So the system did work. 276.454 277.555 ... And then it hardened, 277.555 279.138 and they remove these wooden forms, 279.138 280.185 .. left voids. 280.185 282.380 Vertically and horizontally these forms came together, 282.380 284.248 (H) those voids were filled with grout. 284.248 285.215 Under high pressure. 285.215 287.452 ... Grout being a mixture of concrete and water. 287.452 288.601 ... (H) When this is done, 288.601 291.376 you have what we call a modified monolithic pour, 291.376 293.568 (H) or basically a solid block of concrete, 293.568 297.237 (H) which when completed would be six hundred and sixty feet across the base, 297.237 299.245 (H) fourty-five feet across the top, 299.245 302.187 (H) twelve hundred and fourty-four feet from wingtip to wingtip, 302.187 305.229 (H) seven hundred and twenty-six point four feet high. 305.229 309.063 ... . 309.063 313.871 ... That's enough concrete to build a two-lane highway (H) from New York City to San Francisco. 313.871 314.562 ... O=r, 314.562 315.313 put another way, 315.313 318.459 (H) a four-foot wide sidewalk from the North Pole to the South Pole. 318.459 320.785 .. (H) Then they had to protect that concrete a little bit, 320.785 323.728 (H) the next thing they had to do then is build a couple of spillways. 323.728 326.260 (H) As you got out of your cars or your busses this afternoon, 326.260 327.816 you may have noticed those spillways. 327.816 328.543 (H) Here they are, 328.543 329.686 one on either side. 329.686 330.808 .. (H) What they did, 330.808 331.507 is they came in here, 331.507 334.400 and they blocked these diversion tunnels off in this area through here, 334.400 336.328 ... (H) closed these gates up here, 336.328 339.126 (H) now this yellow part is forever under water. 339.126 340.500 (H) Underneath that lake out there, 340.500 341.699 and completely useless. 341.699 343.281 (H) But they did incorporate, 343.281 344.791 into the design of the dam, 344.791 346.950 (H) the balance of those diversion tunnels, 346.950 349.996 .. (H) using these outer two as spillway tunnels. 349.996 351.582 (H) Now these spillways were built, 351.582 353.106 so that the top of the spi=llway, 353.106 356.066 (H) is twenty-seven feet lower than the top of the dam. 356.066 360.121 .. (H) This assures us that n- any excess water coming down the Colorado River, 360.121 362.260 (H) rather than overtopping the dam, 362.260 364.772 (H) overtops these spillways on either side, 364.772 366.261 (H) goes into the canyon wall, 366.261 367.225 around the dam, 367.225 368.850 (H) out in the river down below. 368.850 374.900 .. (H) Each one of these spillways is capable of handling (H) two hundred th=ousand cubic feet per second of water. 374.900 377.856 .. (H) That's the same amount of water that goes over Niagara Falls. 377.856 380.358 .. (H) three times higher than Niagara Falls does, 380.358 382.653 (H) time that water reaches this area down in here, 382.653 384.709 (H) it is flowing at between one hundred, 384.709 386.764 (H) and one hundred and twenty miles an hour. 386.764 389.016 ... (H) Okay we have protected the spillways, 389.016 390.548 (H) now they had to get some water, 390.548 392.095 .. (H) %- into the power plant. 392.095 394.626 ... What they did is they built four intake towers. 394.626 396.714 (H) Two on either side of the (H) river, 396.714 398.037 on ledges above the river, 398.037 400.754 (H) each of those towers that you saw out there in that lake, 400.754 403.271 ... are three hundred and ninety-five feet high. 403.271 406.446 ... Each with two-eleven-by-thirty-two-foot gates in them, 406.446 407.703 (H) one gate near the bottom, 407.703 408.784 one about half way up, 408.784 410.212 (H) to let the water in. 410.212 412.273 (H) The water then coming into the penstocks, 412.273 414.182 (H) like the one we're standing over right now. 414.182 415.438 ... (H) This penstock, 415.438 417.204 you can see on either side of us out here, 417.204 418.468 (H) is three stories high, 418.468 419.879 or thirty feet in diameter, 419.879 422.963 made of two-and-three-quarter-inch steel boilerplate. 422.963 425.360 .. (H) Made in section twenty-two feet long. 425.360 429.277 .. Each section weighing approximately (H) a hundred and fifty tons. 429.277 432.248 (H) Each of these twenty-two-foot sections is joined to the next section, 432.248 434.021 (H) using pressure pins like thi=s. 434.021 436.874 .. (H) The water pressure in that penstock out there this afternoon, 436.874 440.220 (H) approximately two hundred and thirty-four pounds per square inch. 440.220 442.000 ... (H) Okay we have the water this far, 442.000 445.162 now we divert that into thirteen-foot penstocks or water pipes, 445.162 446.814 (H) each one of em going to a turbine. 446.814 449.295 ... (H) The force of the water turns the turbine, 449.295 451.099 which turns the rotor in the generator, 451.099 452.411 (H) and generates power. 452.411 454.564 ... The water then coming on the tailrace, 454.564 455.530 we saw it up there, 455.530 458.911 (H) and going on downstream to be used at least .. six more times, 458.911 460.589 before it reaches the Mexican border, 460.589 461.963 (H) to generate more power. 461.963 465.736 .. (H) Good clean .. reusable non-polluting source of energy. 465.736 468.306 ... (TSK) (H) The cost of the project. 468.306 470.889 ... A hundred and seventy-five million dollars. 470.889 472.143 ... I say project, 472.143 474.060 because that includes the building of the dam, 474.060 476.854 (H) the building of Boulder City about seven miles up the road, 476.854 480.302 (H) the highway and the railway from Las Vegas out here to the dam site, 480.302 483.399 (H) and in southern California they built the All-American Canal, 483.399 485.842 (H) which takes water to the people and the crops, 485.842 487.935 .. of the Imperial and Coachella Valleys. 487.935 491.323 (H) This money was borrowed on a fifty-year term at three-percent interest, 491.323 494.174 (H) and was paid off in fu=ll in nineteen eighty-seven. 494.174 496.063 ... The people who worked here, 496.063 497.806 and they did work twenty-four hours a day, 497.806 501.208 (H) average twenty-four-hour work force was about thirty-five hundred men. 501.208 504.748 .. (H) The most they had at any one time was when they were pouring concrete, 504.748 506.385 (H) fourty-three hundred men. 506.385 509.793 ... (H) The laborers on the job made fifty cents an hour. 509.793 513.058 .. (H) Highest paid man on the project was a power shovel operator, 513.058 515.007 (H) at a dollar and a qu=arter an hour. 515.007 516.603 ... (H) Out of each man's paycheck, 516.603 518.832 the contractor did deduct each day, 518.832 520.771 (H) a dollar and sixty cents. 520.771 522.825 (H) Because the contractor was feeding, 522.825 524.877 (H) and housing the men in Boulder City, 524.877 527.524 (H) and taking them back and forth out here to the job site. 527.524 531.020 ... They did have ninety-six .. industrial deaths. 531.020 534.561 .. The biggest single category of death was classified as falling material. 534.561 536.187 (H) Basically falling rock. 536.187 538.607 ... But they did have some killed by explosion, 538.607 539.777 (H) some by drowning, 539.777 540.995 some by electrocution, 540.995 543.769 (H) and other types of accidents you might expect to have. 543.769 545.348 (H) On a job of this magnitude. 545.348 547.457 ... They did complete the project, 547.457 548.651 two years ahead of schedule, 548.651 549.663 and under budget. 549.663 551.606 (H) Started in early nineteen thirty-one, 551.606 553.783 (H) completed in late nineteen thirty-five. 553.783 556.139 (H) Just twelve days short .. of five years. 556.139 558.082 ... (H) Do I have any questions. 558.082 560.585 AUD: ... What's this overhead pipe here X. 560.585 561.630 BEN: (H) The overhead pipe. 561.630 562.837 (H) That's the fresh air pipe. 562.837 564.928 .. (H) ... In the summerti=me, 564.928 567.904 (H) the temperature of the air outside gets to be as high as a hundred and twenty degrees. 567.904 569.449 (H) So they bring that fresh air i=n, 569.449 572.377 (H) and they pass that fresh air over a sump at the base of the dam, 572.377 575.148 (H) the water in that sump is a constant fifty-three degrees. 575.148 578.530 (H) It cools that air down to between sixty-eight and seventy-two degrees, 578.530 580.516 (H) then they force it back throughout the dam. 580.516 582.699 (H) So it's %air-conditioning without refrigeration. 582.699 584.650 Like a big evaporative cooler or swamp cooler. 584.650 586.590 ... Any other questions. 586.590 587.344 ... Yes. 587.344 588.612 AUD: ... U=h, 588.612 591.056 during the uh ... earthquake this morning, 591.056 592.275 do you have any sensors down here, 592.275 594.004 that .. measure any kind of movement, 594.004 595.885 o=f ... str[uctur]=es, 595.186 595.574 BEN: []. 595.885 596.524 ... Yes. 596.524 597.836 .. W- v- we have several things. 597.836 600.112 .. First place we have three seismographs throughout the dam. 600.112 601.070 (H) We recorded those, 601.070 602.219 but nobody down here felt em. 602.219 603.664 (H) But we do have sensors, 603.664 604.786 built right into the concrete, 604.786 606.431 (H) any movement that concrete makes, 606.431 607.860 .. is measured and recorded. 607.860 609.850 ... And they had very little of it this morning. 609.850 610.593 Very little. 610.593 612.879 ... Any other questions. 612.879 614.699 AUD: ... How far are you sending electricity. 614.699 615.337 California? 615.337 615.836 BEN: .. Okay. 615.836 618.470 .. Fifty-six percent of our power goes to southern California, 618.470 620.321 (H) twenty-five percent of it stays in Nevada, 620.321 622.490 (H) nineteen percent of it goes to Arizona. 622.490 623.682 (H) What the government did, 623.682 626.909 is they got together the delegates from those three states in nineteen thirty. 626.909 630.226 (H) To allocate the power that would be generated here when this dam was completed. 630.226 632.697 .. (H) California was growing very fast at that time, 632.697 634.359 so they asked for and got most of the power. 634.359 635.872 .. (H) But by the same token, 635.872 636.405 Las Vegas, 636.405 638.021 about thirty-five miles up the road here, 638.021 639.192 (H) at that time, 639.192 641.474 (H) was nothing but a watering stop on the railroad. 641.474 642.504 (H) No hotels, 642.504 643.396 no casinos, 643.396 647.165 (H) we asked Las Vegas to take five percent of the power we could produce here, 647.165 648.466 (H) and they agreed to do that. 648.466 650.096 ... But that's all they get today. 650.096 653.777 (H) Because that contract is good through the year two-th=ousand and seventeen. 653.777 655.098 .. (H) So all those lights. 655.098 656.652 You see burning up there in Las Vegas, 656.652 658.674 (H) comes from power from steam plants, 658.674 660.913 (H) owned and operated by Nevada Power Company, 660.913 662.480 (H) using fossil fue=l. 662.480 664.520 They get very little of hydroelectric power. 664.520 665.284 .. (H) Okay folks, 665.284 665.896 you can follow me now, 665.896 666.791 I'm gonna lead us out of here. 666.791 669.939 ... (THROAT) 669.939 673.914 ... O=kay, 673.914 674.692 here we go folks. 674.692 691.867 >ENV: ((FOOTSTEPS_AND_AMBIENT_CROWD_NOISE)) 691.867 692.620 AUD: . 692.620 695.470 BEN: ... Y- yes it's a fantastic job they did down here. 695.470 695.988 AUD: Yeah. 695.988 716.352 >ENV: ((FOOTSTEPS_AND_AMBIENT_CROWD_NOISE)) 716.352 717.837 AUD: About how many people are employed here. 717.837 718.290 Now. 718.290 720.027 BEN: ... Right now there's about two hundred. 720.027 721.952 .. (H) That includes the security people, 721.952 722.579 the guide force, 722.579 723.415 the nursing staff, 723.415 725.709 (H) the people that .. run the computer room, 725.709 726.450 the office force, 726.450 727.838 as well as the people that work on the dam.