Each horizontal line represents 25 billion cubic meters. Water quantities vary dramatically between regions. The average per capita water availability in China is 2,300 cubic meters per year. However, in the North China plain, water availability per capita drops to a staggeringly low 225 cubic meters per year, while in southeastern coastal China it is as much as 32,000 cubic meters. Temporal variability is also striking, as most of the year's rainfall occurs during summer months.
Some rivers provide very little water for the rest of the year.
China's Huang He, or Yellow River, can deliver a maximum flood flow of 22,000 cubic meters per second during the monsoon months. In winter this can drop to only 250 cubic meters per second, a flow that does not reach the sea during that period. Runoff in a wet year can be five to six times that of a dry year. The country now has more than 83,000 dams. However, China's rivers carry large silt loads that diminish reservoir storage.