Authors: Noel; Behn
Thurston reached for the fuse box, let his fingers rest on the handle of the second switch of the fuse box. “This activates the other generator and the last four engines. The major blackouts on Friday took place not long after this switch was thrown.” His hand moved away from the box. “The second generator and four engines are what was required to open the sluice gates in the reservoir. Those gates were so old and resistant that the machines literally blew a fuse getting them to move. Or I should say, blew Prairie Port's fuse. There are indications that no more than one of those reservoir gates was ever meant to be opened, that opening the others may have been an afterthought, as will become evident when we go downstairs.”
The party descended into the immense concrete chamber beneath the glass-fronted control booth. Along the base of two of the area's three walls were large round openings which had been bricked closed. The fourth, or southern, wall was missing, had only the wood-and-metal water gate.
“This structure is a rudimentary shunting terminal not untypical of engineering beliefs in the 1920s and 1930s,” Chester Safra, the expert on hydrology, explained. “As you can see, those pipe openings in the north wall beneath the booth have been sealed shut, but they were the original source of intake from which this entire system evolved. Through those unsealed mouths, thirty-five years ago, was supposed to have gushed the discarded river water which had been used to turn the turbines of the hydroelectric plant overhead.”
Safra pointed to the bricked-over holes in the east wall. “Those were one of two routes of water outtake. The pipes behind them go right through the rock base of Warbonnet Ridge and pour into the Mississippi River.” He pointed to the water gate at the southern end of the chamber, started walking to it. “That was the second route of outtake. By closing the valves in the eastern wall, the water would head for there.”
Jessup and Yates moved up beside Safra, looked beyond the gate into a high, wide concrete tunnel running from their right to their left, from northwest to southeast. The drop beyond the gate to slowly flowing water was twelve feet. A narrow metal stairway zigzagged down the wall beneath to a rusty metal dock and several bobbing motor boats. Farther to the left, water rippled over a series of closed gates.
On Safra's instructions, Jez and Yates peered past those gates to where the tunnel began to curve due south. Lines of round openings were visible on the far, or western, wall.
“That is your second source of intake water,” he told them. “Those are sewerage and drainage tubes leading down from the western hills, bringing in the natural rainshed and spillage. On the other side of the tunnel are the outtake pipes.” Safra pointed in the opposite direction ⦠pointed uptunnel to the northwest. “That's where the reservoir is ⦠where the third source of intake water can be found.”
Thurston took over. “All of this, all the intake and outtake systems, whatever the initial water sources, was controlled from the booth we were just in ⦠until a recent innovation was made.”
They went down the metal steps on the tunnel wall and onto the dock, with Thurston saying, “Going right in this tunnel for a mile and a half brings you to the water gates in Tomahawk Hill reservoir. Follow the tunnel five miles to the left and you're at Mormon State National Bank. Keep following beyond the bank seven and a half miles and you're at downtown Prairie Port.”
Thurston reached into the water, searched below the surface, brought up a long, rectangular metal instrument panel. Attached to its underside, and trailing back down into the water, were several thick cables and twenty-one wires. “I believe this is how your criminals originally meant to regulate the water flow in this tunnel. Automatically. It's a timing device. A homemade device, but ingenious.” He held the instrument out for all to see, tilted up the bottom. “Those cables tie directly into the generators ⦠can activate or shut off the generators one at a time or together. The smaller wires lead to the intake-outtake gates down the tunnel to the left ⦠the section of tunnel between here and the Mormon State bank.
“To make the system operative you set the timing mechanism on the inside. At the specified time the device turns on the generators, then it opens the outtake gates and closes the intake gates. This fills the tunnel with water. At a later moment the device shuts the intake gates and opens the outtake gates. This drains the tunnel of water. The device then shuts down the generator.
“That's how it's now programmed. The original intention of the device's design was to use the natural watershed from the hills for flooding the tunnel ⦠with an exception. A wire may have been connected to one of the small water gates in the side of the reservoir. But I believe some last-minute adjustments were attempted.”
Thurston turned the instrument and tapped its end. “If you look inside you'll see the timing mechanism is scratched and dented, as if someone clumsy, or in a very big hurry, was trying to turn it off or alter it.” He displayed the other end of the device, indicated a large connecting screw. “This was probably the pole for the sluice gates at the reservoir. One of the small gates in the reservoir's eastern wall. A decision to open other reservoir gates seems to have been made on the spur of the moment. The line attached to this pole was most likely disconnected and brought over here.” Thurston walked to the other edge of the dock, indicated a group of cables running along the tunnel wall. “These lead to every reservoir sluice gate, those in the wall as well as the two in the basin floor. The other ends of the cable have been attached directly to the second generator and its four support engines. The splicing and taping here is sloppier than with any of the other connections. It's likely a second person did this work. Someone who was racing the clock. One way or another, the hookup was completed by eight Friday night and tested out right away. We estimate it took another four hours of adjustment before they got the gates to open. Three gates in all ⦠one in the reservoir wall, two on the basin floor.”
“Got the bottom gates to open,” Safra emphasized. “Dismiss the side gate and it's a trickle. Bottom gates opened! Discharged twice as much water as the system was capable of containing. Demolished whole sections of the tunnel network. Sent tens of millions of gallons of water west for the mud instead of going into Prairie Port's sewers and then out into the Mississippi River.” Safra reached over and patted the time device Thurston was holding. “All because of this little hell box. Our good Mister Thurston omitted mentioning that no one shut this hell box off until we came along late last night.”
“The box went on operating?” Jessup asked.
Thurston nodded. “It didn't start the initial flooding on Friday night, but it activated shortly after and shut down the generators. It didn't matter that the device wasn't directly connected to the reservoir gates. Those gates were tied in to the second generator, and the device controlled that generator along with the other. The reservoir gates were hydraulicized. Once the power to them was cut off, they automatically closed. It was holding them open which caused the power drains and blackouts. Opening them under that much water was like tilting up one end of a New York City skyscraper.”
“⦠You said the initial flooding took place on Friday night,” Jez said. “Which Friday night?”
“Last Friday, August twentieth ⦠the night of your robbery.”
“We haven't established when, precisely, over the weekend, the perpetration occurred,” revealed Jez.
Safra put in, “No robbery, I can assure you, could have happened in the cave under the bank after the first flooding occurred on Friday. The area was totally inundated.”
Jez asked, “Do you have some idea when on Friday night the robbers would have had to leave the cave or be inundated?”
“Eleven-forty-five,” Thurston answered.
“Not eleven sharp or one
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. Saturday?” pressed Jez. “Not maybe ten-fifty or midnight?”
“No, sir,” Thurston said. “Our monitoring equipment recorded three specific incidents of power dips other than the ones that began in the middle of last week. Those earlier dips bear the characteristics set when the first generator is operative. The three dips I'm referring to, the later dips, are identical to the characteristics made when the second generator is operative.
“The first of those three dips came at eight
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. Friday and was brief. This, we now know, indicates the second generator was activated and immediately turned off. Activated and turned off, I assume, as a test to see if the equipment would function. Twelve minutes later, at eight-twelve
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the first blackout occurred in the Prairie Port area ⦠a result of the second generator being activated again and given a trial run of perhaps fifteen minutes.
“The dips disappeared until eleven forty-five
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. Then the largest dip of all was registered. I have little doubt that's when the gates opened in the reservoir. When both generators and all six engines were operative. When eighteen million gallons of water came through.”
Yates looked to Safra. “Why would Prairie Port's Department of Sewerage show no record of excessive water in its system until late Saturday afternoon and early Sunday morning?”
Thurston answered for Safra. “The second electric dip at eight-twelve Friday was sharp enough to put their monitoring equipment out of commission. Theirs and the Water Department's. We have special instruments for just such an incident. Their measuring equipment was affected the way a digital clock is affected when power is shut off and then restored. It blinks on and off repeating the time of the disruption. This happened to the display sign on the Prairie Farmer Building. The Prairie Farmer outdoor timeboard kept repeating eight-twelve
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. that night until it shorted out. It seems,” Thurston said not unkindly to Yates and Jessup, “that your robbers presented a calling card of their intentions for all of Prairie Port to see ⦠the flashing eight-twelve on top of the Prairie Farmer Building on Friday night.”
Safra spoke up. “If what the newspapers say is so, and the thieves escaped by boating through the tunnels, which is the only practical way they could leave, it might be that they wanted to catch the Treachery. The Treachery is the curious midstream current flowing in the river along Prairie Port and below. It's a fascination for us hydrologists. The Treachery comes and goes for no apparent scientific reason, but on a very projectable schedule. We thought it might have something to do with the inland flooding and mud so we got that schedule. The Treachery would have been strong until one
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. Saturday, August twenty-first, until an hour and a quarter after the first and major flooding by eighteen million gallons of water. If the thieves had gone through the tunnels under Prairie Port and gotten out into the river and onto the Treachery by one
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. they would have been carried forty miles downstream faster than by car. If they reached the river after one, motors or paddles would have been needed. The Treachery disappears promptly at one
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. Saturday, August twenty-first ⦠does not start up again for another seventy-six days.”
Jessup stood mute.
“Those later floodings,” Yates asked, “the ones after Friday night, August twentieth, did they occur at regular intervals?”
“Precisely at ten twenty-two, as the timing device prescribed,” Thurston answered. “As I mentioned, the device's inner mechanism seems to have been tampered with, but it was set for ten twenty-two. Neither
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. nor
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. was stipulated. There was a second tunnel flood at ten twenty-two Saturday night, August twenty-first. Twelve hours later, at ten twenty-two Sunday morning, there was a third. They were even larger and longer than the first flood. Between them, they spilled another forty million gallons of water into the tunnels. The electricity the generators required for the Saturday and Sunday flooding caused the severest power dips and blackouts ⦠each at ten twenty-two,
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. or
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., as the case might be. After the Sunday morning flood the timing device shifted to a twenty-four-hour cycle and far shorter operative periods. Floods were recorded at ten twenty-two
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. Monday and ten twenty-two
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. Tuesday. The accompanying power dips were less extreme. We estimate seven million gallons were discharged from the reservoir at each instant. Overall, in the five-day period from Friday until we disconnected the device late last night, Tuesday, a total of sixty-two million gallons of water was released into the tunnels ⦠the first half of which flowed right through the Prairie Port sewer system and on out into the Mississippi River ⦠the second half of which was diverted inland, west to the mud.”
Jez took the timing device from Thurston, turned it over, studied the maze of wires and cables. “What sort of person would have the skills to build this ⦠to manage the other electrical and mechanical work? To make fuses and read old charts and rewire and splice into high-voltage lines and get antique generators going?”
Thurston shook his head. “No one I've come across in thirty years with Missouri Power and Electric. Maybe one of those Ph.D.s at the university or up at the aerospace labs could have. They're pretty strong in the wizard department. As I said before, there was wizardry at work down here.”
St. Ives's motorboat led the way through the opening water gates of the partially flooded tunnel. Beyond the gates St. Ives throttled up, trained his twin flood beams on the bending blackness ahead. Thurston rode with St. Ives. Yates and Jessup followed in the boat operated by Safra.