Plan for Taan, Tachia River Diversion Needs Improved Evaluation of Serious Risks, and Ecological Impacts

A major river basin transfer project is being planned for western Taiwan in order to meet predicted growth in demand for fresh water, including that of the factories of the phase 1-3 Central Taiwan Science Park development. Aside from concerns about the pollution that will be discharged from these factories, a further increase in water exploitation and the infrastructure necessary to support it are expected to impact the rivers’ ecological systems, including endangered wildlife in their estuaries, and pose risks associated with earthquake activity in the vicinity of the project. Statements by conservationists at the 183rd Environmental Impact Assessment review plenary on 26 August highlighted these two issues of major concern.

The Taan River-Tachia River Combined Use Water Transport Project (大安大甲溪水源聯合運用輸水工程計) aims to divert 1.5 million tons of water per day from the Tachia River in Taichung County, ostensibly to meet the predicted public water needs of the greater Taichung area. The water will be diverted northwards into a water treatment plant and an irrigation channel in Houli, Taichung, and across the Tachia River to a second treatment plant at the Liyutan (artificial) Reservoir in Miaoli County, via a series of tunnels and pipes. Construction is expected to take four years.

At the meeting on 26 August, lawyer Thomas Jhan (詹順貴) of the Primordial Law Firm (元貞聯合法律事務所 ) in Taipei, who acted on the EIA committee from 2005 to 2007, referred to the Tsengwen Interbasin Tranfer (IBT) Project in Chiayi County, southern Taiwan, which is believed may have been at least partly responsible for the deadly mudslide that buried Shiaolin Village a month ago, a matter currently under investigation. With one mouth of the tunnel of the Taan/Tachia IBT being situated only two hundred metres upstream of the Shihkang Dam, which breached during the magnitude 7.6 earthquake that occurred on 21 September 1999, and with around ten known geological faults and sheer zones within the project area, Jhan said the Taan-Tachia River project appeared to be even more dangerous than the Tsengwen project.

Meanwhile, Wild at Heart Legal Defense Association submitted comments challenging the poor display of understanding and consideration for river ecology by the proponents.

The main recommendations and advice conveyed to the developers included the following:

1. As much importance should be placed upon assessing impacts on the valuable downstream estuarine ecosystem as on the upstream parts of the river, given the high productivity of estuarine ecosystems and the fact that these are parts of the same river system. (The developers have admitted neglecting to carry out a thorough assessment of impacts on the estuaries.)

2. It is false to assume that the diversion of water from one river basin to another will result in the same total ecological abundance and diversity, as the developers’ representatives suggested. For example, the respective functions of the two estuaries for the critically endangered humpback dolphins that use them is also unknown, and therefore it cannot be assumed that simply transferring the water from one place to another will provide the same habitat quality.

3. The humpback dolphins have already been widely recognized by scientists in Taiwan and abroad as facing imminent risk of extinction, as illustrated by their listing as a critically endangered population in 2008 by the International Union for Conservation of Nature (IUCN). This suggests that they are already experiencing greater stress than they can sustain and, therefore, impacts cannot be dismissed as being 'not obvious' or 'insignificant' – even small impacts, when considered in the context of the numerous threats already faced by the dolphins, should be treated as being the straws that are collectively 'breaking the camel’s back'.

4. In order to give the dolphins the best chance of survival through thorough assessment of the potential impacts of development projects, qualified, experienced and unbiased cetacean experts should be consulted for a full review. The Eastern Taiwan Strait Sousa Technical Advisory Working Group (ETSSTAWG), comprising seventeen scientists from around the world, was set up in 2008 to play such a role, and queries can be addressed to the group through its chair, Dr. Peter Ross.