Taiwan's Reservoirs and Water Resource Management
On this "rain island" with an annual rainfall of 2,500 millimeters, water resources are often insufficient. Springs without plum rains and summers avoided by typhoons have made "water shortage alerts" an annual keyword in Taiwan. From Shimen Reservoir to Tsengwen Reservoir, from Feitsui Reservoir to Nanhua Reservoir, Taiwan's reservoir system carries the lifeline for 23 million people's water needs.
Natural Conditions of Taiwan's Water Resources
Abundant but Uneven Rainfall
Taiwan is located in the subtropical monsoon climate zone with an average annual rainfall of about 2,500mm—2.6 times the world average. However, this figure is deceptive because rainfall is extremely uneven in both time and space.
Temporally, about 80% of Taiwan's rainfall concentrates during the May-October wet season, with typhoon season bringing the most concentrated precipitation. A medium-sized typhoon can bring over 1,000mm of rainfall, but this water often comes too fast and heavy, with most flowing directly into the ocean without effective utilization.
Spatially, eastern Taiwan can receive over 4,000mm annually while southwestern areas may get less than 1,500mm. The Central Mountain Range's blocking effect creates obvious rain shadow areas. The Chianan Plain and Kaohsiung Plain—major agricultural areas—are located in the relatively dry southwest, where water demand is high but natural supply is insufficient.
Topographical Impact on Water Resources
Taiwan's steep mountains and short rivers mean the average distance from the Central Mountain Range to the coast is less than 100 kilometers. This topographical feature causes rainwater to flow rapidly into the ocean with poor natural storage capacity.
Rivers west of the Central Mountain Range, such as the Zhuoshui River (濁水溪), Gaoping River (高屏溪), and Tsengwen River (曾文溪), though having larger watersheds, experience extreme flow variations between wet and dry seasons due to steep terrain. The wet season may bring severe flooding while the dry season may see riverbeds completely dry.
Geological conditions also affect water resource utilization. Western plains consist mainly of alluvial layers with abundant groundwater but prone to land subsidence from over-pumping; the east has hard rocks that don't store water easily but provide better quality; the south has limestone terrain that easily forms groundwater systems but is also vulnerable to contamination.
History of Taiwan's Reservoir Development
Japanese Colonial Period: Origins of Modern Hydraulics
Modern reservoir construction in Taiwan began during the Japanese colonial period. Wusantou Reservoir (烏山頭水庫), completed in 1930, was the first large-scale reservoir designed and built by Yoichi Hatta (八田與一), primarily supplying irrigation water for the Chianan Canal. The construction technology was quite advanced for its time, using semi-hydraulic fill earth-rock dam with a storage capacity of 150 million cubic meters.
The success of Wusantou Reservoir transformed the Chianan Plain from rain-dependent fields to fertile farmland, dramatically increasing rice production. This project also established Taiwan's hydraulic engineering technical foundation and cultivated local water conservancy talent.
The Japanese period also built Sun Moon Lake Reservoir (日月潭水庫), primarily for power generation rather than water supply. This reservoir utilized Sun Moon Lake's natural topography to build a hydroelectric power plant, becoming an important foundation for Taiwan's electricity development.
Post-war Reconstruction: Focus on Domestic Water Supply
Post-war Taiwan saw rapid population growth and urbanization, dramatically increasing domestic water demand. The government began planning reservoirs primarily for water supply.
Shimen Reservoir (石門水庫) was completed in 1964 as Taiwan's first large-scale multi-purpose reservoir after the war. This reservoir serves water supply, power generation, flood control, and tourism functions, becoming a model for Taiwan's reservoir construction. Shimen Reservoir primarily supplies Taoyuan and parts of New Taipei, contributing significantly to northern Taiwan's development.
Feitsui Reservoir (翡翠水庫) planning began in 1973 and was completed in 1987. Built specifically for Taipei's water supply, it employs strict watershed management to ensure excellent water quality. Feitsui Reservoir's success made Taipei the only city in Taiwan without water shortages.
1980-1990s: Major Construction Period
During Taiwan's economic takeoff in the 1980s, industrial water demand surged, prompting the government to build reservoirs on a large scale. This period saw completion of important reservoirs including Tsengwen, Deji (德基), and Wushe (霧社).
Tsengwen Reservoir (曾文水庫), completed in 1973, is Taiwan's largest reservoir with a storage capacity of 700 million cubic meters. This reservoir primarily supplies agricultural and industrial water for the Chiayi-Tainan region, playing a crucial role in southern Taiwan's development.
Deji Reservoir (德基水庫), located upstream of the Dajia River, was completed in 1974, primarily supplying the Taichung area. This high-mountain reservoir sits over 1,000 meters above sea level with excellent water quality but faces sedimentation problems from typhoon-induced landslides.
Recent Developments: Rise of Environmental Consciousness
After the 1990s, rising environmental awareness created more resistance to new reservoir construction. Projects like Meinong Reservoir (美濃水庫) and Jiyang Artificial Lake (吉洋人工湖) were halted due to environmental controversies. The public began questioning the necessity and environmental costs of large reservoirs.
Recent reservoir construction focuses on small to medium-scale projects like Hushan Reservoir (湖山水庫) and Agongdian Reservoir (阿公店水庫) renewal. The government also emphasizes maintenance of existing reservoirs, promoting reservoir dredging and facility upgrades.
Major Reservoir Systems
Northern Water Resource System
Feitsui Reservoir is the most important water source for the Taipei metropolitan area and one of Taiwan's most successfully managed reservoirs. Development within its watershed is strictly controlled, maintaining excellent long-term water quality. The reservoir uses dual-layer intake facilities, allowing water extraction from different levels based on water quality conditions.
Shimen Reservoir serves Taoyuan and parts of New Taipei as an important water source for northern Taiwan. However, this reservoir faces serious sedimentation problems with effective storage capacity declining annually. The government is promoting the Shimen Reservoir renewal project, including dredging and dam heightening.
Xinshan Reservoir (新山水庫), Chengfu Reservoir (成福水庫), and other small to medium reservoirs provide supplementary water supply functions. Though modest in scale, these reservoirs play crucial roles during dry seasons.
Central Water Resource System
Deji Reservoir is located upstream of the Dajia River as Taichung's main water source. This high-mountain reservoir has excellent water quality, but due to fragile geology in its watershed, typhoon rains often bring massive landslides, causing serious sedimentation.
Liyutan Reservoir (鯉魚潭水庫) supplies Miaoli with an off-channel design that avoids main river sedimentation problems. This design concept was later applied to other new reservoirs.
Hushan Reservoir (湖山水庫) is Taiwan's newest major reservoir, beginning operation in 2016, primarily supplying Yunlin. This reservoir employs modern design with comprehensive monitoring systems and environmental protection measures.
Southern Water Resource System
Tsengwen Reservoir is Taiwan's largest reservoir, operating in conjunction with Wusantou Reservoir to form the Tsengwen-Wusantou system. This system is the main source of agricultural and domestic water for the Chiayi-Tainan region, irrigating 150,000 hectares.
Nanhua Reservoir (南化水庫) supplies parts of Tainan and Kaohsiung with relatively new design concepts and good water quality protection measures. However, this reservoir's watershed is relatively small with limited water supply capacity.
Agongdian Reservoir (阿公店水庫) is Taiwan's first earth-rock dam with long history but aging facilities. Recent renewal and reconstruction have improved water supply capacity and safety.
Gaoping River Weir (高屏溪攔河堰), though not a reservoir, is an important water source facility for Kaohsiung. The weir raises water levels to improve intake stability.
Water Resource Management Challenges
Sedimentation: The Chronic Disease of Reservoirs
Taiwan's reservoirs universally face serious sedimentation problems. Due to fragile watershed geology, typhoon rains often bring massive sediment that accumulates in reservoirs, reducing storage capacity.
Shimen Reservoir faces the most serious sedimentation, with effective storage capacity declining from the original 200 million cubic meters to 170 million cubic meters. Deji Reservoir has a sedimentation rate of 47%, severely affecting water supply capacity.
Dredging is the main solution to sedimentation but is costly with limited effectiveness. The government recently promoted the "Enhanced Reservoir Watershed Conservation and Management Project," hoping to reduce sediment inflow from the source. New dredging technologies like hydraulic desilting and land excavation are also being developed.
Water Quality Protection: The Dilemma Between Development and Conservation
Water quality protection in reservoir watersheds is an eternal issue. Activities like agriculture, animal husbandry, and tourism within watersheds can impact water quality. The government must balance economic development with water quality protection.
Feitsui Reservoir has the strictest management with development banned in its watershed and even visitor access restricted. This strict control ensures excellent water quality but limits local development.
Other reservoirs have more relaxed watershed controls but face greater pollution pressure. Tsengwen Reservoir's watershed includes agriculture and tourism, making water quality management more complex. The government is promoting ecological engineering and pollution reduction measures, hoping to balance development and conservation.
New Challenges from Climate Change
Climate change brings new challenges to Taiwan's water resource management. Changing precipitation patterns and increasing extreme weather events may make traditional water resource planning methods obsolete.
Taiwan has recently experienced frequent "spring rain absence" phenomena, with reduced plum rain season precipitation preventing effective reservoir storage. The 2021 century-long drought saw multiple reservoirs reach historically low storage rates, highlighting climate change threats.
Changing typhoon paths also affect water resources. Typhoons that previously brought abundant rainfall to Taiwan now often pass by, reducing precipitation replenishment. Even when typhoons do strike, they may be too intense with rainfall too heavy and fast for effective utilization.
Regional Water Resource Imbalance and Distribution
North-South Disparity: Contrasting Water Abundance and Scarcity
Taiwan's water resource distribution is extremely uneven, creating obvious north-south disparities. The north has large reservoirs like Feitsui and Shimen with relatively abundant water sources; the south has large reservoirs like Tsengwen but faces greater water demand pressure.
The Taipei metropolitan area, with Feitsui Reservoir's abundant water source, rarely faces water shortage crises. Even during the severe 2021 drought, Taipei maintained normal water supply. Conversely, central and southern regions frequently face water shortage concerns.
This disparity results not only from natural conditions but also historical development. The north, being politically important, received more water infrastructure investment; the south, despite agricultural development, has relatively insufficient water facilities.
Competition Between Agricultural and Domestic Water Use
Agricultural water use accounts for over 70% of Taiwan's total water consumption, but agriculture contributes less than 2% to GDP. With economic structural transformation, pressure increases to transfer agricultural water to domestic and industrial use.
Water resource allocation in the Chiayi-Tainan region is most complex. The Tsengwen-Wusantou system primarily serves agricultural irrigation, but industrial areas like Tainan Science Park also require substantial water. Managing different demands within limited water resources is a major challenge for management units.
The government promotes agricultural water transfer policies, encouraging farmers to reduce irrigation during dry seasons and transfer water resources to domestic and industrial use. However, this approach has sparked farmer backlash, believing it hinders agricultural development.
Technical Challenges of Inter-regional Water Transfer
To solve regional water resource imbalances, the government has planned multiple inter-regional water transfer projects. However, Taiwan's complex topography presents significant technical challenges for inter-regional transfers.
The "South-to-North Water Diversion" project hopes to transfer southern water resources north but is suspended due to high costs and technical difficulties. "East-to-West Water Diversion" hopes to utilize eastern abundant rainfall to supplement western water needs but faces similar topographical barriers.
Currently feasible options are short-distance regional distributions, such as joint management between Taipei and New Taipei, or support between Taoyuan and Hsinchu. Though modest in scale, these measures can play crucial roles during emergencies.
Development of Alternative Water Sources
Seawater Desalination: Obtaining Water from the Ocean
Facing water resource shortages, seawater desalination has become an important alternative. Taiwan, surrounded by sea, has stable seawater desalination advantages unaffected by climate.
Taiwan currently operates multiple seawater desalination plants, including offshore islands like Penghu, Kinmen, and Matsu, as well as mainland locations like Tainan Yongkang and Hsinchu. These facilities primarily use reverse osmosis technology with continuously declining desalination costs.
However, seawater desalination has limitations. High energy consumption—producing 1 ton of freshwater requires 3-5 kWh; high-salinity wastewater discharge may impact marine environment; high facility maintenance costs requiring professional technology. Whether seawater desalination can develop on a large scale depends on overcoming these challenges.
Reclaimed Water Utilization: Circular Economy Practice
Reclaimed water involves treating wastewater for reuse—an important method of water resource circulation. Taiwan's reclaimed water is mainly used for industrial cooling, landscape irrigation, and toilet flushing.
Hsinchu Science Park pioneered reclaimed water use, building reclaimed water plants in the 1990s to supply park companies. This successful experience was later promoted to other science parks.
Promoting domestic reclaimed water faces difficulties, mainly public acceptance issues. Though treated reclaimed water is high quality, most people have psychological barriers. The government is promoting reclaimed water education to change public perceptions.
Rainwater Harvesting: Local Resource Wisdom
Rainwater harvesting is an ancient but effective method of water resource utilization. In highly urbanized Taiwan, rainwater harvesting not only increases water sources but also reduces urban flooding risks.
The government promotes "Building Site Rainwater Storage Facility Standards," requiring new buildings to install rainwater storage facilities. These facilities can collect rooftop rainwater for irrigation and cleaning purposes.
Community rainwater harvesting systems are gradually being promoted. By installing large water storage facilities, entire communities can share rainwater resources. This approach particularly suits Taiwan's rainy but unevenly distributed climate characteristics.
Future of Smart Water Management
IoT Technology Applications
Internet of Things technology brings revolutionary changes to water resource management. Installing sensors at reservoirs, pipe networks, and user endpoints enables real-time monitoring of water levels, quality, and flow rates for precise management.
Taiwan Water Corporation is promoting the "Smart Water Network" project, using smart water meters, pressure monitoring, and leak detection technologies to improve water supply efficiency. These technologies can detect leaks early, reducing water resource waste.
Reservoir management also incorporates IoT technology. Through weather monitoring, water level warning, and automated operation systems, more precise water resource allocation is possible. Artificial intelligence applications can predict water demand and optimize supply strategies.
Digital Twin Technology
Digital Twin technology recreates physical water infrastructure in virtual space, simulating various scenarios to evaluate different strategy effectiveness.
This technology is particularly suitable for reservoir operation management. By building digital reservoir models, water level changes under different rainfall scenarios can be simulated to develop optimal operation strategies. It can also evaluate engineering improvement plan effectiveness, reducing actual construction risks.
Pipe network management can also apply digital twin technology. Building comprehensive pipe network digital models can simulate pressure changes and leak impacts, assisting maintenance planning.
Artificial Intelligence Prediction
Artificial intelligence shows enormous potential in water resource prediction. By analyzing historical weather data and water usage data, rainfall and water demand can be more accurately predicted.
For short-term prediction, AI can forecast water demand for upcoming days, assisting water source allocation. Long-term prediction can assess climate change impacts and plan future water infrastructure.
Extreme event early warning is an important AI application. By analyzing weather data, drought or heavy rain warnings can be issued early, gaining response time. This is particularly important for Taiwan with its dramatically changing climate.
International Experience and Taiwan's Learning
Singapore's Four Taps Strategy
Singapore is a successful model of water resource management, with its "Four Taps Strategy" worthy of Taiwan's learning. The four taps include local catchment, imported water, reclaimed water, and desalinated water, ensuring water security.
Singapore's reclaimed water technology is particularly advanced, with reclaimed water quality suitable for direct drinking. The government successfully changed public perception of reclaimed water through "NEWater" branding. This experience is very enlightening for Taiwan's reclaimed water promotion.
In seawater desalination, Singapore continuously improves technology, reducing costs and energy consumption. Its desalination plants use the most advanced membrane technology with dramatically improved efficiency. Taiwan can reference its technology and management experience.
Israel's Water-Saving Agriculture
Israel developed advanced water-saving agricultural technologies in arid regions, including drip irrigation, micro-sprinkler irrigation, and integrated water-fertilizer systems. These technologies dramatically improve water resource utilization efficiency, turning deserts into oases.
Though Taiwan isn't an arid region, agricultural water consumption is enormous, making water-saving agricultural technology equally important. The government is promoting smart agriculture, including precision irrigation and soil monitoring technologies, hoping to improve agricultural water efficiency.
Israel's water pricing policies are also worth referencing. Through tiered water pricing encouraging conservation; heavy taxation on excessive water use to suppress waste. Market mechanisms are more effective than administrative controls.
Sustainable Future of Taiwan's Water Resources
Facing challenges from climate change and population growth, Taiwan must establish a more sustainable water resource management system requiring joint efforts from government, businesses, and citizens.
Technically, we must continue developing reclaimed water, seawater desalination, and smart management technologies to improve water resource utilization efficiency. We must also improve existing facilities, including reservoir dredging and pipe network replacement.
Institutionally, we must establish more reasonable water pricing mechanisms reflecting true water resource costs. We must also improve water rights systems enabling effective allocation between different uses.
Socially, we must strengthen public water conservation education, cultivating conservation consciousness. Businesses must also assume social responsibility, adopting water-saving technologies and reducing waste.
Water is the source of life and foundation of economic development. On this beautiful island, we must treasure every drop of water, wisely manage water resources, and ensure future generations can also enjoy abundant clean water sources. This is not only the government's responsibility but everyone's mission.
Further Reading: