As an avid off-roader and one that drives through lots of swampy water in the NJ Pine Barrens there are a few things that you need to know.
1. Open the hood of the vehicle on a nice day and look for the air intake. This is your "I can't go any deeper than that" point. If you do you will suck water into the intake and through the carb or throttle body then into the engine. Engine does not burn water. Engine is done, you're stuck and have major repiars to do to engine. Don't ask me how I know this.
2. Before entering water; standing of moving, get some sort of stick and walk throuch the water, measuring how deep it is. Use this as a reference for your intake point.
3. If you think you can make it safely through the water, put the vehicle in 4wheel low with the transmission in low gear and slowly, very slowly drive through the water. You want to cause as little wake as possible. Keep moving slowly, don't stop unless you absolutely have to. If you stop the water that you have pushed with the vehicle will usually come back to the vehile and you may have a wave higher than your intake point.

Slow and steady wins the water race.