Roberts looked up a little surprisedly, but a few words from Fields explained the situation, and the newcomer turned to Roger quite affably.
"Certainly, my boy, it's very simple," he said. "You see, all work on rivers, whether for the purpose of irrigation, flood control, or navigation, is dependent on the amount of water that flows through that river channel every year. A week of wet weather makes a vast difference to the amount of water the river is carrying, and a dry spell cuts it off."
"But don't springs and things keep the water about even?" queried the boy.
"No, indeed," answered his informant emphatically. "Why, the Tennessee River, which I worked on once, for three months never flowed more than 20,000 cubic feet per second, yet that same year, for fifteen days in the spring, it tore down with over 360,000 feet a second. In other words, in the spring it was as big as eighteen rivers its usual size."
Photograph by U.S.G.S.
Measuring Stream Flow.
Trolley line one mile long, over an Eastern river. Instruments pulled up, ready for return to the bank.
"Are all rivers like that?"