...it seems unlikely that asauropod coming from say, a flood plain away from the coast, would find bodies of water 80 feet deep all over the place. +++++++++++++++++++++ ??? Why is deep water necessary? +++++++++++++++++++++++
Ah, I think I've misled you slightly as to my point. I was commenting on why the snorkling hypothesis is untenable, I was not implying that sauropods were completely hydrophobic and/or could not swim. The original (early 1900's? late 1800's?) snorkling hypothesis held that the animals sat on the bottom of a pool with the head just breaking the surface. This requires deep water. If you're asking whether a sauropod might wade into 4 meters of water and find something quick to munch, then you are proposing a much more reasonable situation that does not require a 'snorkle' in the first place. In fact, if the animals are just wading (or even swimming on the surface) lung collapse is no longer an issue. Surface swimming would inhibit breathing a bit because sauropods are just so big and the lungs are therefore still several meters underwater. That is a far cry from being dozens of meters (or more) under the surface, however. So yes, I would agree they could swim. Heck, a lmost every terrestrial animal can swim. No reason not to ford a river...sitting on the bottom is just not a feasible option.
Especially if the neck can not be raised much from the horizontal.