TM, they both have 38" hind tires, so the axles are quite high. How deep would you have to go into the water??
As far as parts, many parts for both are still availlable through the dealer network, the rest are readily availlable form salvage yards. Both are quite common tractors.
as long as you keep the axle seals and all gaskets in good shape you shouldn't have any trouble wading some water.