[vkou]

There's plenty of water, but aquifers are tend to be tapped in areas with insufficient rainfall/access to rivers.

If you're drawing on the aquifer faster then it replenishes, it'll eventually run out. Sure, it'll replenish itself - eventually - but the land you were cultivating will be unusable for decades. In the meantime, all of your nice topsoil will turn to dust, and blow away.