Scope:
1.This project includes the construction of a new stilling basin structure, protective works, secant piles, improvements to the existing stilling basin, and other associated works.
2.The stilling basin measures 38 meters in length and 66 meters in width, with a 1.5-meter-thick base slab and a 0.5-meter-thick abrasion-resistant layer.
3.At the downstream section of the stilling basin, concrete interlocking blocks were used for scour protection, transitioning seamlessly with the existing ground elevation using hollow concrete armor blocks.
4.A total of 173 secant piles, each 1.5 meters in diameter and embedded over 3 meters into the bedrock, were installed to prevent excavation-induced impacts on existing structural and slope foundations.
5.Additional work included consolidation grouting under the existing gates and intermediate overflow weir foundations,
Benefits:
The Qingtan Weir has long suffered from scouring caused by typhoons and heavy rainfall, resulting in downstream riverbed erosion, significant displacement or loss of energy dissipation blocks in front of Gates 3 through 6, and seepage issues beneath the dam foundation. Continued scouring posed a threat to the weir structure due to potential riverbed undermining. Moreover, during peak flood events, the water level downstream of the weir falls below the tailwater level required for proper energy dissipation, indicating insufficient dissipation capacity in the stilling basin. This project was therefore undertaken to enhance the long-term safety of the Qingtan Weir, restore its functional performance, and ensure effective energy dissipation under design flood conditions.
Project Cost:USD 5.6 million
Construction Period:November 2019 – June 2021
![Taiwan.gov.tw [ open a new window]](/images/egov.png)
