As a kid growing up on Bald Top Mountain above the Susquehanna River in Pennsylvania, Van Wagner would look down during times of low water to see a mysterious âVâ rising from the bottom, pointing downstream. Later, he learned it was an old eel weir built from stacked river rocks, a simple but effective way to funnel and catch migrating American eels. As the eels swam downstream, the walls of the weir funneled them to a narrow point where they could be captured in traps or speared more easily. As Wagner shows in a recent drone video, the two walls of the weir rise about 3 to 5 feet from the river bottom. The weir is about one-eighth of a mile wide at the top of the V.