Liberty Times: You once said that the nation would be burdened with chronic water problems, including “floods when it rains, and droughts when it does not.” With the nation facing perhaps its worst water shortage in decades, what are your thoughts as to the reasons? Does Taiwan inherently lack water supplies, or is it failing to retain them?
Hwung Hwung-hweng (黃煌煇): In research by the 2013 World Economic Forum on factors affecting the world economy the most, water resources were listed as the second-highest factor. In this year’s survey, they have become No. 1. The lack and mismanagement of water resources heavily affects the global economy, and Taiwan’s situation is a reflection of this situation.
Taiwan’s average annual rainfall is 2,500mm. The problem is that we cannot retain the water.
Taiwan’s annual rainfall is [almost] three times the world average of 900mm, and is the second-highest in the world, with more than 90 billion tonnes per year. However, we only have 18.5 billion tonnes to use the year over, which puts the average water supply available per person at 3,950 cubic meters, far less than the global standard of 32,000 cubic meters per person. Taiwan is in 18th place in UN global rankings in terms of being a “water-resource-poor region,” and second-to-last in terms of available water sources.
More than 80 percent of the rainwater that falls on Taiwan is lost, with 50 billion tonnes per year flowing out to the sea. What is retained is often insufficient to cover domestic use, leading the nation to draw more than 5 billion tonnes from underground water sources. Such a situation means Taiwan is not only constantly lacking water, it are also causing another sort of environmental destruction.
LT: Are the frequency of floods and water shortages increasing?
Hwung: The changes in climate have caused rain to fall over a shorter period. In the Taipei area, rainy days have decreased by 28 days per year over the past two decades, but the volume of rain per day has increased, even exceeding the amount of water displacement the city is able to handle, leading to flooding.
The majority of rain in Taiwan, about 70 to 90 percent, is concentrated in the summer, and the island is reliant on the plum rain season — as well as typhoons — to bring in water. However, the number of typhoons making landfall has decreased, and those that have made landfall have brought less precipitation.
Moreover, our reservoirs are clogged with sediment and their capacity for water storage is declining.
Under such circumstances, the frequency of water shortages is naturally increasing.
Previous administrations never really made water resource management a focus of their policies.
They forgot the pain of water shortages as soon as the rains ameliorated the situation. It is evident that the government has not paid any attention to or made any effort to implement water management.
This shortsighted attitude of relying on nature will not help the nation retain its water.
LT: Sediment clogging reservoirs is a normal occurrence, but it seems the government’s efforts — the NT$5 billion (US$158.86 million) devoted to removing sediment after Typhoon Morakot and the NT$60 billion five-year project — have not had any effect. What do you think?
Hwung: The 46 major reservoirs were originally designed to have a total capacity of 43 billion tonnes. However, due to the severity of sediment deposits, we can only store 22 billion tonnes, not even half the designed capacity. The amount of stored water simply cannot keep up with the annual nationwide use of 10 billion tonnes.
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