Ripples are periodic waveforms throughout the natural environment. These subaqueous asymmetrical wave ripples in sand under the Pee Dee River in North Carolina are created by oscillatory wave motions normal or slightly oblique to the shoreline.
Sand bar, shore line, subaqueous ripples and tree stump on the Pee Dee River, Morrow Mountain State Park, NC. This photograph ©Andy R. Bobyarchick.