Why are countries like China turning to desalination compared to other ways of increasing water supply?

Question

Hi i m rather stuck when trying to answer this question.

Do help me out TY.

Answer 1

China has 22 per cent of the world's population but only 7 per cent of all freshwater runoff. China's freshwater supplies have been estimated to be capable of supporting 650 million people on a sustainable basis - only half the country's population. Despite periodic flooding, particularly in the southern part of the country, China faces chronic water shortages in the northern part.

Already, China is practising what water expert Sandra Postel calls the "zero sum game of water management" - when authorities increase water supply to one user by taking it away from another. China's Yellow River is a classic example of this. The river is so over-used that, for an average of 70 days a year for the past decade, its waters have dried up before reaching the Bohai Sea. Crops have withered in the once rich delta so that upstream factories and farms could take all the water.

There is no time to lose for China to beef up its efforts in water pollution control if it wants to tackle the problem of serious water shortage, a top legislator warned Wednesday in Chongqing.

Addressing a symposium of the National People's Congress (NPC) on the protection of environment and resources, Sheng Huaren, Vice-Chairman of the NPC Standing Committee, said China is facing a severe challenge in its water pollution control.

Though the country has made great efforts to control water pollution, Sheng said, "there are still serious problems."

Pollution infiltrates from tributaries into larger rivers, fromsurface water into groundwater, and from land to ocean, Sheng said.

Today, developing the seawater (including brackish water) desalination technology has become a consensus of all the countries in the world to solve the water crisis. China has a long coastline of 32,647 kilometers; and the coastal regions and the central and western regions also boast abundant ground brackish water resources. Under the circumstance that drawing ground water and transferring water across regions are restricted by more and more conditions, developing and exploiting seawater and brackish water resources and practicing seawater desalination have become an effective and important strategic approach to relieve the tension of fresh water deficiency in China.

Compared with trans-regional water transfer, seawater desalination enjoys obvious advantages. Trans-regional water transfer involves project investment, operation fees, management fees, and losses like evaporation, seepage, river closure and pollution, as well as the occupation of large amount of lands; moreover, along with the advancement of technology and the expansion of the handling capacity per day, the cost of sea water desalination has been reducing continuously. Consequently, the cost of seawater desalination will be lower than that of water transfer.    

Moreover, water transfer is also influenced by the water capacity of the supplying region. Once the water source areas suffer from low water, the regions introducing water will become very passive. While sea water desalination, is not influenced by time, space and climate and also is of good water quality and stable water supply.

Answer 2

In the desalination process if you are success you can forget about the water requirements for centuries together.They think for future rather than temporary solutions.