Climate Change Impacts and Responses: a Case of Shihmen Reservoir in Taiwan*

Climate Change Impacts and Responses: A Case of Shihmen * Reservoir in Taiwan Paper prepared by Keshav R Adhikari1, Yih-Chi Tan2, Jihn-Sung Lai3, Zueng-Sang Chen1, 3 Yong-Jun Lin 1Dept. of Agril. Chem., National Taiwan University (NTU), Roosevelt Rd, Sec. 4, Taipei city 106-17, Taiwan; For correspondence: [email protected] 2Dept. of Bioenviron. Systems Engg., NTU, Roosevelt Rd, Sec. 4, Taipei city 106-17, Taiwan 3Center for Climate weather and Disaster Research/Hydrotech Research Institute, NTU, Taipei City 106-17, Taiwan * Paper prepared for oral presentation at the 2nd Int’l conference “Climate Change: Impacts and Responses.” University of Queensland, Brisbane, Australia, 08-10 July 2010. 2 Climate Change Impacts and Responses: A Case of Shihmen † Reservoir in Taiwan Abstract Built in 1964, one of the oldest and magnificent in Taiwan, the Shihmen reservoir serves the multi-purpose of supplying fresh water (3.4 million people), irrigation (36, 500 ha), hydro-power (200 million units electricity annually), flood prevention and recreation. Scientific observations show that this reservoir is over time affected by increased frequencies of high sedimentation and overflows, due to unpredictable high rainfall and typhoons necessitating heavy repair and maintenance costs. This clearly illustrates an effect of global warming making such phenomena visible at local level (urban heat island effect, for example). A review of existing body of literature on Shihmen reservoir indicated that most previous studies focused from their own disciplinary perspectives. However, the relevant stakeholders of the reservoir including the practitioners and policy makers would be better served if such studies considered using system- approach. In this paper, we attempted to present the case by integrating salient features of both natural and human dimensions to identify potential areas that future management would find helpful to combat the effects of climate change. Utilizing the desktop information, we presented a macro-perspective of the case in hand to derive what interventions would be necessary from both private and public sectors to maintain the functioning of the reservoir. These led us to emphasize that for reduced risk of the climate change impacts and improved sustainability, all processes of decision-making and collective actions involving individual participants and the community at large, should put integrated efforts, develop robust upstream conservation regulations and adhere to the principles of an eco-friendly environment of the reservoir. Key words: Climate change, Shihmen reservoir, eco-friendly, policy, participation 1. Introduction Taiwan’s specific location at the juncture of Pacific, Eurasian, and Philippine Sea plates is subject to frequent earthquakes (Figure 1). Some earthquakes have caused major damage, such as the 1999 Chi–Chi Earthquake, which left 2,455 dead and 11,305 injured (Chen at al., 2006). Taiwan is also vulnerable to typhoons because it is located in the path of west Pacific typhoons. Roughly 3 or 4 typhoons strike Taiwan each year. Latest super typhoon (Morakot) occurred during August 5-10, 2009; death exceeded 700 and caused huge losses of public and private properties (Adhikari et al., 2009). Direct economic losses of Taiwan reach about 10 billion New Taiwan Dollars every year from floods due to typhoon (Hsu et al., 1995). As believed by many, †Paper prepared for oral presentation at the 2nd Int’l conference “Climate Change: Impacts and Responses.” University of Queensland, Brisbane, Australia, 08-10 July 2010. 2 3 recent typhoons resulting to high rainfall and greater floods over the past few years is in part the consequence of global warming. The Chi–Chi Earthquake shook the ground heavily paving the way for the following rains to easily produce a greater amount of debris flows. Similarly, Morakot typhoon produced mudflows of the extent that the whole village residing in the lap of a mountain in south Taiwan was buried under its solid mass. Although, such impacts appear to be determined largely by global or regional phenomena or processes, it is also reasonable that to a certain extent, the impacts could be accelerated or mitigated by the local policy and actions. Figure 1: Map of Taiwan showing the island surrounded by seas and located at the interface between the Eurasian Plate and Philippines Plate. In this paper, an attempt has been made to present the concept of climate change affecting the performance of Shihmen Reservoir of Taiwan aimed at deriving some policy implications for sustainability and beneficial uses of the reservoir. The paper is divided into 7 distinct but interrelated sections: The concept of climate change related to the reservoir, heat island effect, the reservoir environment, changes in effective water storage capacity of the reservoir, rehabilitation of the reservoir, and strengths and weaknesses with the reservoir related government policy, and conclusions. 2. Climate change and theoretical underpinning Over time, the climate change has been more contentious subject among scientists. Despite a strive for the true science, recent literature shows that both consensus and skeptics prevail in the scientific world and the debate continues spanning around whether the climate change is a fact or just an anomaly (noise in the environmental data). Amidst these debates, some fundamental points are agreed by all that increasing greenhouse gas (GGs) concentrations tend to warm the planet (Intergovernmental Panel on Climate Change, IPCC, 2007). The most abundant GGs are water vapour, carbon di-oxide (CO2), atmospheric methane, nitrous oxide (N2O), ozone, and 3 4 chlorofluro-carbon (CFCs). The two sides of the greenhouse effect are that: without it, the Earth would not be warm enough for humans to live, but if the effect becomes stronger, it could make the Earth warmer than usual. Even a little extra warming may cause problems for humans, plants, and animals. In computer-based models, rising concentrations of these gases produce an increase in the average surface temperature of the Earth. Rising temperatures may, in turn, produce chain effects such as faster melting of ice, sea level rise, changes in precipitation patterns, and storm severity commonly referred to as "climate change." Greater rise in temperatures and CO2 concentrations on the Earth atmosphere in more recent times are primarily attributed to the human causes of industrial revolution, burning of fossil fuels, deforestation, agricultural practices (mainly low- land rice), and the urbanization with increased uses of home appliances such as air-conditioning facilities, and so on. Assessments by IPCC suggest that the Earth’s climate has warmed between 1.1° and 1.6°F over the past century and that human activity affecting the atmosphere is "very likely" an important driving factor. However, it is a fact that local and seasonal variations are much larger than the globally averages. In the case of Taiwan, transformation of the subsistence economy into the industrial economy in the last 50 years brought the nation to the status of one of the three Asian Tiger Economies. However, it did not happen without significant policy changes in land and water resource development and uses. After industrial development and urbanization, it seems plausible that Taiwan also exhibits a heat island effect. In one way or the other, this effect works in combination with other drivers of climate change contributing to the changed weather pattern in the island which may also affect the performance of local natural resources including the water bodies or reservoirs located in the surrounding natural landscapes. Does then heat island effect constitute an element of the climate change? 3. Heat island effect in Taiwan Describing the urban heat island phenomena, Akbari (2005) characterizes urban areas as having higher air temperatures than their rural surroundings as a result of gradual surface modifications that include replacing the natural vegetation with buildings and roads. As urban areas develop, changes occur in their landscape. Buildings, roads, and other infrastructure replace open land and vegetation. Surfaces that were once permeable and moist become impermeable and dry (except in deserts). These changes cause urban regions to become warmer than their rural surroundings, conceptually forming an "island" of higher temperatures in the physical landscape. Taiwan is relatively a small island (36000 km2) and presents a case of heat island effect primarily due to rapid industrialization and associated increases in urban population density (602 people/km2) (Lin et al., 2005). Research evidences show that this has caused the diurnal temperature increases by about 1.1oC since 1950, which is about twice the corresponding values over the major continents. Owing to rapid economic growth and living standards, energy consumption increased up to about 20 times in the last 4 decades in Taiwan. The big cities in western plains such as Taipei, Taichung, Chiyai, and Kaohsiung cities have suffered from a regional scale heat-island effect (Lin and Tsai, 2005) and it is clearly visible on the remote 4 5 sensing images (Liu et al., 2002). The impact was measured by making pairwise comparison where about 88% of the urban-rural pairs exhibited negative urban-heat island values during the daytime due to the impact of denser urban developments. Records show that annual and daily temperature fluctuations have also increased in Taiwan (Hsu and Chen, 2002) and these

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