1.2 Surface Water Resources
In 2017,the quantity of surface water resources was 2,774.63 billion m3,equivalent to 293.1 mm of runoff in depth,which was 3.9%more than normal and 11.3%less than that in 2016.
Among the Class I WRRs,the Northwest Rivers,Pearl,Yangtze,Southwest Rivers and Huaihe had an annual quantity of surface water resources more than normal,in which the Northwest Rivers had an annual quantity 27.5%more than normal;and the Liaohe,Haihe,Songhua,Yellow and Southeast Rivers all had an annual quantity less than normal,in which the Liaohe and Haihe had an annual quantity 46.0%and 40.6%less than normal,respectively.Compared with 2016,except the Yellow and Southwest Rivers,which had an annual quantity of surface water resources 15.0%and 2.4%more,respectively,all the other Class I WRRs had a less annual quantity of surface water resources to a varying extent,in which the Liaohe and Southeast Rivers decreased by 42.8%and 42.0%,respectively.See Table 3 for the 2017 annual quantity of surface water resources and comparison with 2016 and normal by Class I WRRs.
Among the PARs,15 had an annual quantity of surface water resources more than normal,in which Guangxi,Hainan and Qinghai had a quantity over 25.0%more than normal;Yunnan had a quantity close to normal;and 15 had a quantity less than normal,in whichInner Mongolia,Hebei and Liaoning had a quantity over 40%less than normal.Figure 4 shows comparison between the 2017 quantity of surface water resources and normal by PARs.
In 2017,21.86 billion m3 of water flowed from abroad into China;625.04 billion m3 of water flowed from China to abroad;and 93.42 billion m3 of water flowed from China into international border rivers.
In the whole country,the total quantity of water flowing into the sea in 2017 was 1,694.13 billion m3,in which 7.99 billion m3 was from the Liaohe,3.50 billion m3 from the Haihe,8.24 billion m3 from the Yellow,55.48 billion m3 from the Huaihe,969.70 billion m3 from the Yangtze,173.92 billion m3 from the Southeast Rivers,and 475.31 billion m3 from the Pearl.Compared with 2016,the water quantity flowing into the sea in 2017 decreased by 388.42 billion m3,and all the other Class I WRRs had a decreased quantity of water flowing into the sea to a varying extent,except the Yellow and Huaihe,which had a quantity increasing by 10.0%and 5.8%,respectively.
Table 3 The 2017 quantity of surface water resources and comparison with 2016 and normal byClass I WRRs
Figure 4 Comparison between the 2017 quantity of surface water resources and normal by PARs