How much water does clonal eucalyptus need and will it lower my water table?

Eucalyptus is a fast growing tree and it does use water, but the common belief that it always destroys the water table is exaggerated for normal farm planting on suitable land. The real concern is in dry, low groundwater areas where large dense blocks of eucalyptus can add to water stress, so placement and scale matter. On good land with reasonable rainfall or some irrigation, clonal eucalyptus grows well and the water use is acceptable for the returns. To be sensible, avoid planting big solid blocks right next to wells or shallow aquifer areas in water scarce regions, give early irrigation for establishment, and match the planting scale to your water situation. If your area already has falling groundwater, plant in moderation or choose boundary and bund planting rather than large blocks.