Note that the groundwater depletion map is 1900 - 2008. Unless there is some actual correlation with recent groundwater depletion, any correlation with Gates farmland purchase seem pretty meaningless, in terms of him causing groundwater depletion. Now an alternative hypothesis is that he knows something that would make that farmland more valuable than what he paid, whether that relates to groundwater is yet to be known.
Note that the groundwater depletion map is 1900 - 2008. Unless there is some actual correlation with recent groundwater depletion, any correlation with Gates farmland purchase seem pretty meaningless, in terms of him causing groundwater depletion. Now an alternative hypothesis is that he knows something that would make that farmland more valuable than what he paid, whether that relates to groundwater is yet to be known.