“The reason given was that the lack of water would interfere with navigation, but when you realize that it isn’t until the Rio Grande flows a thousand miles on the other side of the Mexican boundary that any navigation begins, you can see how ridiculous that objection was. We were able to get this treaty broken at last and have substituted a new one in its place. Under this new treaty we guarantee to deliver to Mexico a certain minimum number of gallons of water a year and we are at liberty to do what we like with the remainder. By building this dam we will give Mexico only one-tenth of the total amount stored each year, yet that one-tenth is more than half as much again as they are getting now!”
“That new treaty clears up the biggest trouble, then, doesn’t it?” said Bob. “But in the early days of settlement I wouldn’t have thought that the Mexicans would have enforced the old treaty.”
“I don’t suppose they could,” returned Mr. Whitney, “but the uncertainty kept many a prospective irrigator from spending his time or energy in the work. Now, however, even Mexico is strong for the completion of the big dam, as it will irrigate a lot of her land which before was desert. Besides, it will cost them nothing and that always appeals to folks—including Mexicans!”
“It certainly is going to be some big dam,” said Bob, waving his hand over the work spread out below them. “How high is it going to be?”
“If I remember the figures exactly, it will be two hundred and twenty-five feet from the foundation to the top—almost as tall as the Flatiron Building in New York. It will be nearly twelve hundred feet from bank to bank across the top.”
“It will have to be awfully thick, won’t it, to be able to hold the water?”
“It’ll be twenty feet through at the top. At the bottom it has to be pretty nearly two hundred feet. Although it is all filled in now by masonry, they had to dig down to bedrock and to get there they had to excavate about five hundred and fifty thousand cubic yards of sand, shale and rock. It’s sixty-five feet from the river bed to the bottom of the foundation.”
“That must’ve been some job. I wish we had been here to do it, don’t you, Mr. Whitney?”
The man smiled at the boy’s eagerness. “There will be other jobs for us to do,” he said, “where we’ll go through with it from the start to the finish. I wouldn’t be a bit surprised if about the time you have graduated from college we would be ready to begin work on the Labyrinth which you and Jerry found. You’ll come out to be my chief assistant and we’ll do the whole thing.”
“That’ll be great,” said Bob, his face glowing. “But go ahead about this dam. I’m learning more than I have all the time I’ve been here poking around by myself. It ought to make a pretty big lake when once the water is dammed up, shouldn’t it?”