No thats not a wallow, that looks like a stock tank on hot summer day.
A wallow looks like a mud hole. The bulls urinate in it and then roll in it, the wallow will smell like a barn yard. If you are down wind you will smell the wallow before you see it, same with the bulls.
In the summer on really hot days the elk will wade out into a stock tank up to there bellies to drink and cool off. If you happen to have some really hot weather during the Sept. hunts its a good idea to take a stand on a stock tank during the hottest part of the day.