“Makes you think of a pasture lane fenced in with stone, doesn’t it?” inquired Roy with a smile. “But how in the world can two stone walls have anything to do with making the channel deeper?”
Smiling over Roy’s perplexity, Mr. Anderson replied, “That’s exactly what these jetties are, in fact--a kind of lane for the waves to go through. There are two bars that obstruct the entrance to this harbor, which otherwise is one of the finest in the land. Over the outer bar there were only twelve feet of water, and at the inner bar nine and a half feet. An ocean liner draws twenty-five or thirty feet, you know, and couldn’t possibly get over such a shallow place. That meant that Galveston, though ideally situated for a seaport, could never be reached by big ships. The government kept dredging the channel, but the shoals filled up about as fast as the dredges dug them out. Finally Uncle Sam’s engineers solved the problem by building those big stone walls.”
“Even now I don’t understand what the stone walls have to do with deepening the channel,” said Roy, still perplexed.
Mr. Anderson chuckled. “Those stones, as you call them, are granite blocks weighing five to twelve tons each,” he said. “The jetties are twelve to fifteen feet wide at the top and so solid that the water can’t flow through them; so it has to run between them, exactly like cattle going down your pasture lane. The tide runs so fast that it washes the loose sand out of the channel, scouring it clean every day, as it were. The result is that now Galveston has a thirty-one-foot channel at high water.”
Roy whistled in astonishment. “That beats anything I ever heard of,” he said. “It was a pretty slick idea, wasn’t it?”
Steadily the _Lycoming_ ploughed her way along between the jetties. As they drew near the shore ends of the jetties, Roy noticed that the long south jetty ran directly to Galveston Island, while the shorter north jetty ended at a small island in Galveston Bay. Mr. Anderson said it was called Pelican Island.
But what immediately gripped Roy’s attention was the great wall that began at the end of the south jetty and ran around the outer side of the city. Vaguely he remembered having heard of the Galveston sea-wall, and he knew this must be it. He was amazed as he looked at it. Evidently the wall was of cement, for it appeared like a solid piece of stone. Its seaward side was concave, being far wider at the base than at the top. Its base was protected by a wide riprap of huge granite blocks, evidently intended to prevent the waves from undermining it. Roy wondered how the waves could ever get up to the wall, let alone threaten it, for a stretch of beach, fully two hundred feet wide, lay between the wall and the waves that were now breaking on the glistening sands.