This first photo is low tide below the dam. Note how the water comes through the spillgate and fans out down the apron of the dam.


This photo was taken about a half an hour after the one above. Note how the flow through the spillgate has been pinched into the center of the apron as the tide rises.


The photo below shows the flow through the spillgate being further restricted by the rising tide.


Finally, full high tide below the dam. The current rushing through the spillgate has been turned into a swirling back eddy below the dam.