Recent(ish) errata gave all WiGE Combat Vehicles the effect of the Flotation Hull, so as to be able to float on water.
As per
Total Warfare (corrected 6th printing/2020 edition) p. 55 ...
While grounded, a WiGE vehicle has 1 Ground MP, and is considered a hover vehicle for terrain restrictions. A grounded WiGE vehicle can enter a hex using the Minimum Movement rule (see p. 49), provided it is not prohibited from entering that hex.
... and ...
Water: All WiGE vehicles float on water and so treat water hexes as clear terrain, including when taking off and landing, though they cannot descend below Depth 0. When landed on water, these vehicles are treated as as naval vehicles for purposes of line of sight, etc.
Does this mean that a WiGE landed on water would still be able to use that 1 Ground MP to turn or taxi on the water surface, just as it does on land (and also as a 1 MP hover vehicle would be able to)? As per the above, a WiGE is not prohibited from entering a water hex.
EDIT Edited to clarify edition of TW.