Droughts a dilemma that will not go away

By Chang Yen-ming 張炎銘  / 

Fri, May 13, 2011 - Page 8

The issue of droughts has reared its ugly head again. Water and electricity are basic necessities. Taiwan has a power reserve of more than 20 percent, but what about water?

In 2009, Taiwan used roughly 19 billion cubic meters of water. However, its reservoirs had an effective overall capacity of just about 2 billion cubic meters and supplied approximately 8.1 billion cubic meters of water, not including water for power generation. The rest of the water used that year came from rivers and ground water.

Taiwan does not have enough space to store water and has no reserve margin. When climate conditions become abnormal, the government needs to think about drought control. If just 20 percent of Taiwan’s yearly average rainfall of approximately 90 billion cubic meters were to be saved, no one would have to worry about droughts.

Although the government has promoted a development plan for the diversification of water resources, all methods involve costs. Desalination and recycling of wastewater require large amounts of energy. If recycled water is to be provided for public use, certain psychological impediments will have to be removed at the user end, which is no easy task.

Using manmade lakes or wetlands to improve the quality of water and then putting it to further use involves using land resources in exchange for water resources. Building reservoirs can damage the river environment. Extracting ground water can cause land subsidence, while building weirs still makes obtaining water dependent on the weather.

In short, there is no perfect way of going about drought control.

In the face of Taiwan’s most recent drought, the Water Resources Agency has already begun to use rain stimulation, but this requires specific climatic conditions and there are limitations to how much water it can produce. This method also requires that rain falls on the upstream catchment areas of reservoirs, which is very difficult to guarantee.

Sending water from rainfall in the north down south and from rainfall in the east of the country to the west means not only having to hope that rain will fall in certain restricted areas, but it also involves huge investments in water transportation and water compression equipment, which is simply not feasible from an economic perspective.

In addition, as Taiwan is such a small island, will the north really collect enough extra water to send to central and southern Taiwan? This is impractical. What’s more, the whole of western Taiwan is an area with a high risk of water shortages.

Conserving water is the best way to go about dealing with droughts. While the government has gone to great lengths to promote water conservation, low water prices has meant that these efforts have not been very effective. The government must start conserving water for agricultural purposes and encourage moves toward precision agriculture and dry-land farming.

Over the years, the last and only method Taiwan has had to combat droughts has been to stop irrigation and leave farmland fallow. However, it is unfair to sacrifice agriculture, and according to the Water Act (水利法), water for agricultural purposes continues to be given a higher priority than water for industrial use. Given the overall economic losses this could mean, it is probably the final effective solution available to us.

However, in a future where abnormal climatic conditions could very well become more prevalent, both droughts and floods will become more extreme. How will we be able to have our cake and eat it too?

Chang Yen-ming is a former director of the Taichung branch of the Water Resources Agency.