“We had been hoping all along that the Austrians might let the water go on piling up behind the dam until it gave way, but it was not till one day when our scouts brought word that the gates had now been opened, with the evident intention of holding the lake at a level which they figured at about ten feet above the danger-point, that it occurred to us that we might do something to help the good work along. Nobody ever recalled afterwards whose idea it was, but a dozen of us—officers and men together, in the Serbian fashion—suddenly found ourselves waving our arms and getting red in the face discussing a plan for building a little dam of our own, backing up as big a lakeful of water behind it as we could, and then turning it loose on the big lake below at the crest of the spring floods. If any of us had had any engineering sense we’d have known that we couldn’t build—with no tools but a few axes and spades, and no materials but what nature had put there—a dam in a year big enough to be of any use, let alone in a month. But having no sense to speak of in things of that kind, we went ahead with the job, and, with the luck of fools, pulled it off.
“There was a fine site for a dam at the upper end of the cart-road gorge, where it looked as though a solid barrier thirty feet high would back up a lake something like three-quarters of a mile long and from a quarter to half a mile wide. We began by building a ‘crib’ of pine-trunks thirty feet wide—which was to be filled with boulders and gravel. On our pencil plan of it, it was to be heavily buttressed from below and slope from both sides till it was only ten feet wide at the top. Our idea was to make it as much like a fort as possible, so that if the Austrians piped it off from an aeroplane they would think we were only working on defences. A hole was to be left in the middle for the river to flow out through, as we didn’t intend to store water till the big rains and thaws set in. As it was rainy or windy every day from the time we started to work, the Austrians—as far as we ever knew—did no flying over the mountains, so that we had no worry on that score.
“Upwards of five hundred husky Serbs can do a deal of work, but it didn’t take more than three days of log-rolling and rock-packing to show that—even at the pace we were hitting it—that hundred-yard-long, thirty-feet-high dam wouldn’t be finished before the next season, and that, even if we did get it done some time, the stuff we were putting in it was too loose to stop water. It was at this stage of things that I had my big idea. I had worked in hydraulic mines in the West, and while we had nothing to rig up a pipe and nozzle from, there was a chance to divert a little mountain torrent that came tumbling down from the snows only a few yards below our dam site. Why not, I suggested, build up only a narrow crib of boulders and pine logs to act as a barrier, and then bring over this little torrent—it was flowing about a hundred miner’s inches at this time—and let it sluice down the loose ‘conglomerate’ from the four-hundred-foot-high cliff through which it flowed? Because no one had anything else to offer, we decided to try the thing.
“We used up a good half of our poor little store of powder in making the cut to bring over the stream, but the job was mostly easy digging, and we finished it in three days. My young ‘hydraulic’ sure tore down a lot of rock and gravel, but, as we couldn’t rig up anything to confine it properly, it only spread out in a big ‘fan,’ which in turn was sluiced away by the river. That fairly stumped us, and when on top of it a big storm came on and brought down a flood that washed away all our cribbing, we chucked up in disgust our project of ‘harnessing nature’ against the Austrian and began to plan raids again.
“All that night it rained cats and dogs, and when I looked out of my hut the next morning the river was over its banks and humping it like a ‘locoed’ mustang. But the funny thing was that the cascade from the little stream we had diverted seemed to have disappeared. At first I thought it had bucked its way back into its old channel, but when I went down to look I found that it had been ‘swallowed’ up by the cliff. Five times as big as on the night before, it came tumbling down over an up-ended stratum of slate, to disappear in a foamy yellow-white spout into a deep crack it had sluiced into the soft ‘conglomerate.’ At the bottom of the cliff it came boiling out from under the angling slate-layer in a stream that looked to be about equal parts of gravel and water. My baby ‘hydraulic’ had evidently undermined a sloping section of the cliff for a hundred feet or more, and only the tough slate stratum was staving off a big cave-in. How big a cave-in it was going to be, and what it was going to lead to, I never guessed.
“The warm rain kept plugging down all day, and was still pelting hard when I went to sleep that night. Towards morning I was waked up with a roar a hundred times louder than any snow-slide I ever heard, and then came a jar that rocked the whole valley. I felt sure a piece of the cliff had come down, but didn’t have the least hunch that anything like what the first daylight showed up had come off. The first thing I saw as the dark slacked off was the shimmer of a flat stretch of water in the bottom of the valley, a lake—just as if it had been dropped from the sky—right where we’d been trying to start one ourselves.
“The cliff had broken back a couple of hundred feet or more all the way to the top, and in falling had piled up clear across the head of the gorge. On the near side it was about one hundred and fifty feet high, on the farther side something like sixty.
“With the rain still pouring pitchforks and the snow melting all over the mountains, water was coming down at a rate that had the lake rising at the rate of two feet an hour all morning, and better than half that fast even when it began to spread out over the valley floor in the afternoon. The storm kept right on for three days. The second morning there was twenty-five feet of water at the dam, on the third forty feet and on the fourth near to fifty. The lake by this time was both bigger and deeper than the one we’d planned to make ourselves.
“By good luck the streams ramping down from the mountains into the gorge below the slide kept two or three times its average flow in the river, and so the Austrians—who didn’t know its habits very well—failed to notice that anything unusual had come off up-stream. Our scouts reported that the water in the lower lake had not risen much, and that it seemed to stand at about fifteen feet above the danger mark. The Austrians, they said, did not appear to be paying any more attention to the dam than usual.
“We were hoping that the storm would hold until enough water was backed up to bust the dam on its own, but when it began to clear on the fourth day it was plain the best way out of it was to give the thing a push on our own account. We didn’t have a hundredth of enough ‘giant’ to do the job, so had to rig the best makeshift we could by turning the still husky stream of my ‘hydraulic’ right along the sloping top of the slide and off down into the gorge.