The sandy beaches of Nebraska. I can attest to them being there. Elkhorn has/had a water ski lake I have water skiied at hundreds if not thousands of times. I tried to barefoot there but all I did was wipe out. I gave up trying to barefoot and then went to trick water skis and had a blast.
There were other three other lakes down south of Offutt Air Force base. I water skiied there thousands of times.