Taiwan Water Resources & Management

Despite receiving substantial annual rainfall averaging around 2,500 millimetres — roughly 2.6 times the world average — Taiwan faces persistent water security challenges. The island's steep terrain causes rapid runoff into the sea, while rainfall is concentrated in the typhoon season (May to October) and unevenly distributed across geographic regions. Managing this paradox of abundance and scarcity is central to Taiwan's water policy.

Governance and Institutional Framework

The Water Resources Agency (WRA), established under the Ministry of Economic Affairs (MOEA), serves as the national authority for integrated water resource management. WRA is responsible for water rights administration, reservoir operations, river channel management, groundwater regulation, and drought and flood response coordination. Regionally, eight River Management Offices oversee specific river basins, while Taiwan Water Corporation and local water bureaus manage municipal supply systems.

Taiwan's water governance framework is grounded in the Water Act, which regulates water rights allocation, permits for water extraction, and inter-agency coordination. The WRA also maintains a comprehensive real-time monitoring network encompassing over 1,200 hydrological stations measuring rainfall, river flow, reservoir levels, and groundwater depths. This data is integrated into the Drought Early Warning System (DEWS) and published publicly to support transparent resource management decisions.

Reservoir Infrastructure and the Sedimentation Challenge

Taiwan relies on 21 major reservoirs for public water supply, irrigation, hydroelectric generation, and flood control. The combined design storage capacity is approximately 2.5 billion cubic metres. Key facilities include Tsengwen Reservoir in Tainan (the largest, with a designed capacity of 708 million cubic metres), Shimen Reservoir in Taoyuan, Wushanto Reservoir in Chiayi, and Feitsui Reservoir in New Taipei (dedicated to Taipei metropolitan supply).

Sedimentation is the most significant structural challenge facing Taiwan's reservoirs. Typhoon Herb (1996) and Typhoon Morakot (2009) deposited catastrophic quantities of sediment into multiple reservoirs, with Tsengwen Reservoir losing an estimated 70 million cubic metres of capacity following Morakot. WRA has deployed hydraulic flushing, sluicing operations during flood events, and mechanical dredging programs to recover capacity. The Reservoir Sedimentation Management Master Plan outlines long-term strategies including upstream watershed revegetation, check dam construction, and sediment bypass tunnels to intercept sediment before it enters reservoirs.

Drought Response and Climate Adaptation

Taiwan experienced one of its most severe droughts on record in 2020-2021, when 56 years of accumulated data were broken as major reservoirs dropped below 20% capacity in several regions. The WRA activated Stage 3 and Stage 4 water rationing — suspending agricultural irrigation, requiring industrial users to reduce consumption by 7-11%, and implementing rotational supply cuts for households. The government deployed six emergency mobile reverse osmosis desalination units in coastal areas and fast-tracked approval for temporary deep aquifer drilling.

In response to increasing climate variability, Taiwan's climate adaptation strategy focuses on three pillars: diversifying water sources (expanding seawater desalination capacity, promoting rainwater harvesting at the building level, and accelerating reclaimed water treatment plant construction), upgrading distribution efficiency (replacing aging pipes to reduce pipeline leakage losses, which currently account for approximately 13% of supply), and strengthening demand management (tiered pricing structures, industry water efficiency audits, and public conservation campaigns).

Water Recycling, Reuse, and Future Policy

Taiwan enacted the Reclaimed Water Resources Development Act in 2015 to provide a legal basis for reclaimed water as a public resource. Under this framework, major industrial parks and science parks — particularly in water-stressed southern Taiwan — are required to progressively meet water reuse targets. The Southern Taiwan Science Park and the Tainan Technology Industrial Park operate advanced membrane bioreactor (MBR) treatment systems supplying reclaimed water for cooling and process applications.

By 2025, the government targets a reclaimed water supply capacity of 1.32 million cubic metres per day nationwide. Additionally, the Water Resources Agency has promoted smart water management technologies, including sensor-based leakage detection in distribution networks, AI-assisted reservoir inflow forecasting, and real-time demand response platforms. Taiwan's experience in balancing high rainfall with structural scarcity positions it as a reference model for other island and mountainous economies facing similar climate-driven water security dilemmas.

Frequently Asked Questions

Which agency oversees water resource management in Taiwan?

The Water Resources Agency (WRA) under the Ministry of Economic Affairs (MOEA) is the primary authority responsible for water resource planning, development, conservation, and allocation in Taiwan.

How many major reservoirs does Taiwan have?

Taiwan has over 20 major reservoirs with a total design storage capacity of approximately 2.5 billion cubic metres. Sedimentation remains a significant challenge reducing effective capacity.

How does Taiwan handle water supply during droughts?

Taiwan activates a tiered water rationing system including agricultural water suspension, industrial reduction schedules, household conservation appeals, and emergency aquifer pumping.

What is Taiwan's strategy for managing typhoon-related flooding?

Taiwan invests in flood management infrastructure including retention ponds, flood diversion tunnels, river levee reinforcement, and real-time monitoring systems integrated with weather bureau alerts.

Is Taiwan expanding its water recycling and reuse capacity?

Yes. Under the Reclaimed Water Resources Development Act (2015), Taiwan targets 1.32 million cubic metres per day of reclaimed water capacity by 2025, with mandatory reuse quotas for industrial parks.