There are some nice air-breaks and drops in the upper part of this photo, just below the ripples. You’d look for bedrock, of course, but first, you’ll want to find the exact water-break where the floodwater allows the gold to drop straight down through an air pocket. Gold wants to fall first, and will be ahead of all the other heavy minerals, slightly upstream from the sand, where the gravel falls and the heavier metals will be found.