These are time-lapse videos of the Gualala River mouth in Northern California during the months of February, March & April, 2009, taken by Dane Behrens, a PhD student in Environmental Science at UC Davis.
They were taken with a time-lapse package from Harbortronics (www.harbortronics.com) at 20-minute intervals. This was taken with the permission of Don and Jan Plenty, who let me use their property to station the camera.
This is part of a research project to study how rivers in Northern / Central California respond to environmental forcing (waves, floods, etc.).
The following video was taken on January 11, 2009, at 2:00 pm, about 2 hours after the Gualala river opened. The opening occurred after head difference between the estuary and the ocean waters grew as the tide went out. The sand at the narrowest point in the beach liquefied, opening the mouth. Initially, the flow was thin sheet flow over the beach, but as the velocity increased, these forms started to pop up.
Standing waves in the mouth of the Gualala River