Does Eucalyptus cultivation affect the water table / ground water of the land?

No, Eucalyptus does not deplete the ground water table. About 90% of the roots will be restricted within 5 meters depth and only a 10% of the roots can go up to a depth of 10 meters.  Hence, it will make use of the water available in the top 10 meters depth of the soil only. Eucalpytus species is an efficient water user. Its transpiration loss is less due to the leaf adaptation. The water up taken by the tree is efficiently used to produce high biomass.