Water Flowing over a Concrete Spillway

The crest of a spillway like this is usually built in a gentle S-curve called an ogee. Its shape follows the path water would take if it fell freely, so the flow stays pressed to the concrete instead of tearing away from it. Here a broad white sheet pours down the face between stained walls into a churning river, with a wooded hillside beyond. You can almost hear the roar in this dam spillway jigsaw puzzle.