One of the biggest challenges facing China’s future development is water, which must support the country’s 1.4 billion people and booming industries. Despite being one of the top five countries with the largest freshwater resources, on a per capita basis, China faces serious water shortages which are further compounded by a highly uneven spatial distribution and precipitation: the densely populated north suffers from acute water shortages whereas the south is prone to severe floods. To optimize the allocation of water resources, China has embarked on the construction of a mega engineering project, the South North Water Diversion project (SNWD).