Though a desert land devoid of the abundant natural resources often needed for life to thrive, modern Saudi Arabia has always been capable of growth. The driver of this growth -- hydrocarbons beneath the earth -- mean that lower oil prices hurt the Saudi economy, exacerbating other issues, namely its growing population with high youth unemployment. These domestic concerns have been just as daunting to the Saudi government as have shifting foreign policy priorities in the region. Austerity measures and perpetual tweaks to Saudization look to address some of the more pressing employment and public spending issues. Riyadh has also laid out lofty goals for the next decade and a half with its Vision 2030 policy. But the question now is what could hamper these ambitions. And underneath it all is one of Saudi Arabia's main resource constraints: water....