Seven Policies For Government to Consider--- 3. Building more Water Desalination Plants

First I do a Deepseak of the percentage share of each origin of water in Hong Kong.

In Hong Kong, the water supply comes from three main sources: local yield, the Dongjiang (East River) from Guangdong Province, and desalinated water. Here's a general breakdown of their percentage shares:

Dongjiang (East River) Water: The majority of Hong Kong's water supply, approximately 70-80%, comes from the Dongjiang in Guangdong Province. This is the primary source due to Hong Kong's limited local water resources.

Local Yield: Local water sources, including rainfall collected in reservoirs, account for about 20-30% of the total supply. However, this percentage can vary significantly depending on rainfall patterns.

Desalinated Water: Desalination contributes a small but growing share, currently around 1-2%, as part of Hong Kong's efforts to diversify its water sources and enhance water security. The Tseung Kwan O Desalination Plant, commissioned in recent years, is expected to increase this share over time.

These percentages can fluctuate based on factors such as rainfall, water demand, and infrastructure.

The percentage share of Water desalination plant is obviously small and local yielded sources vary significant depending on rainfall pattern. Therefore the majority of Hong Kong’s water supply comes from Dongjiang (East River) water from Mainland China. This is unsustainable for two reasons: first, water is a scarce resources and according to Boston Consulting Group, water will be the most valuable commodity in future years and China’s South-to-North Water Diversion is somewhat hindered by supplying water to Hong Kong; second, The current rate for Dongjiang River water is above market equilibrium, so the mainland thinks it is a burden to supply scare water to Hong Kong while Hong Kong thinks they are overpaying water resource from China. In summary, neither of mainland and Hong Kong are happy with the current arrangement, creating a lose-lose situation. So it leaves building more desalination plants the only option to diversify water sources.

For the specific implementation such as the location of more desalination water plants is pending more information. Preliminarily, there are to be built in Lantau Island, outlying islands such as Cheung Chua or Lamma Island, and Tseung Kwan O (for expansion). Among the options, I favoring expanding on the current Tseung Kwan O water desalination, building new ones in Lantau Island, and ones in outlying Island. The former comes naturally as expanding current facilities should be the cheapest and easiest among the options. The latter builds on current government development of northern Lantau Island development project and Lantau Tomorrow Vision. The government should consider building water desalination plants in these new developments 

*The green part is generated by Deepseek.