Black Heart and White Heart by H. Rider Haggard

When Nanea leapt from the dizzy platform that overhung the Pool of Doom, a strange fortune befell her. Close in to the precipice were many jagged rocks, and on these the waters of the fall fell and thundered, bounding from them in spouts of spray into the troubled depths of the foss beyond. It was on these stones that the life was dashed out from the bodies of the wretched victims who were hurled from above. But Nanea, it will be remembered, had not waited to be treated thus, and as it chanced the strong spring with which she had leapt to death carried her clear of the rocks. By a very little she missed the edge of them and striking the deep water head first like some practised diver, she sank down and down till she thought that she would never rise again. Yet she did rise, at the end of the pool in the mouth of the rapid, along which she sped swiftly, carried down by the rush of the water.

Fortunately there were no rocks here; and, since she was a skilful swimmer, she escaped the danger of being thrown against the banks.