Wading depth is set by the manufacturer of your vehicle and is determined by a number of crucial factors. These include the location of sensitive electronics, the air intake, and other venerable areas. Often the manufacturer will assume you’ll only be wading for a few minutes, so if you intend on regularly crossing rivers some additional preparation may be required. Consult an expert if you’re considering a serious expedition. It’s a good idea to have a reference point on the vehicle as an indication of the wading depth – usually the top of the wheel rim is a safe bet.
It probably would not have been something so much out of the ordinary, if the whole thing was being done with boats and other amphibious vehicles. Instead, `regular army trucks` (if there is anything regular about this) are acting as a submarines, crossing the streets of the town