Just a guess here, but we're thinking that metal post sticking up out of the water was a marker for the deep hole that this unfortunate guy drove his Jeep into.    

This dunking happened at the Badlands Off Road Park in Attica, Indiana, when the Wabash River had overflowed its banks and encroached on the trail system.  The driver doesn't seem too upset by the turn of events, but then again he hasn't started assessing the damage yet either.  Or it's not his Jeep.