Qualla: Shigang Dam

Shigang Dam: Introduction

Sat, 13 Jun 2026 00:00:00 GMT

Photo credit 李元顥, Public domain. On the morning of September 21, 1999, at 1:47 a.m., the earth beneath central Taiwan moved so violently that a dam split open. The 921 earthquake — named for its date — ruptured the Chelungpu Fault and killed approximately 2,400 people across the island. At the Shigang Dam on the Dajia River, the northern end of the structure simply collapsed, dropping several meters as the ground beneath it lurched. The broken section was never repaired. Instead, the twisted concrete was preserved exactly as the earthquake left it, an open wound in the landscape that now draws visitors from across Taiwan who want to understand, in physical terms, what seismic force actually looks like.

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Image: 李元顥 | Public domain

Shigang Dam: Built to Last, Then Broken

Sat, 13 Jun 2026 00:00:00 GMT

Photo credit Kai3952, CC BY-SA 4.0. Construction of Shigang Dam began in 1974 and was completed in 1977, a concrete gravity barrage dam stretching 357 meters across the Dajia River and standing 35.2 meters high. Its reservoir, originally capable of holding 3.38 million cubic meters of water, served two purposes: fl...

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Image: Kai3952 | CC BY-SA 4.0

Shigang Dam: The Memorial That Stayed

Sat, 13 Jun 2026 00:00:00 GMT

Photo credit Fcuk1203, CC BY-SA 3.0. After the collapse, engineers built an embankment cofferdam to prevent water from flowing uncontrolled through the gap. That practical solution allowed the reservoir to continue functioning for agricultural use, even though the original flood-control capacity was gone. What it di...

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Image: Fcuk1203 | CC BY-SA 3.0

Shigang Dam: Water That Still Flows

Sat, 13 Jun 2026 00:00:00 GMT

Photo credit Kai3952, CC BY-SA 4.0. Despite the damage, Shigang Dam continues to serve the region. It is no longer rated for flood control — the breach means that function is impossible — but water still collects in the reduced reservoir and still supplies irrigation channels that feed Taichung's agricultural distr...

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Image: Kai3952 | CC BY-SA 4.0

Shigang Dam: Reading the Fault

Sat, 13 Jun 2026 00:00:00 GMT

Photo credit 李元顥, Public domain. The 921 earthquake registered 7.6 on the moment magnitude scale. Beyond the approximately 2,400 people who died, more than 100,000 homes were damaged or destroyed across central Taiwan. The economic and psychological impact on the island was enormous. In the years that followed, ...

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Image: 李元顥 | Public domain