With the South China Sea in front and the five Maintains behind, Guangdong has a mild climate and numerous rivers with a long-term annual rainfall of 1700mm. Merely counting the drainage areas above 100 km2, there are 543 rivers within the boundary of Guangdong, among which 4 are more than 10000 km2(Dongjiang, Xijiang, Beijiang and Hanjiang). Total amount of water resources is 186 billion m3 in the province, of which 133.3 is surface water, and 52.7 underground. Additionally, another 233 billion m3 of water pass through Guangdong from the neighboring provinces, making its hydropower potential up to 10730 megawatts, of which 6,660 can be tapped.