Riverbank Erosion Control, Zhuoshui River, Changhua, Taiwan

Zhuoshui River, located in Central Taiwan, encounters the problems of the shrinkage of flood plain during the rainy season from May to October during which the riverbanks are markedly vulnerable to erosion. At the downstream of the river which is primarily composed of sediment threatens the stability of the river dyke because of the shrinkage of flood plain.

Used to apply spur dam to serve as the river bank protection with the defense flood level could be up to 24000 m³/s; yet, due to the long-term erosion against foundation at the spur head, it caused the loss of soil and local settlement of the structure resulting in the destruction of gabion shield and the exposure of the pier head.

The ACETube^® geotextile tubes were used to protect the flood plain slope and shelter the foundation of the PC spur dam. First, a layer of polypropylene ACETube^® paved both sides of the dam’s foundation to retard base subsidence. The ACETube^® were then filled to different heights or stacked together to stabilize the foundation, and to reduce the effects of scour and improve the effectiveness of siltation at the pier heads. Also, at the most severe erosion sites, gabions overspread the ACETube^® and gaps were filled with local sand to amplify the overall erosion resistance of the structure. On the flood plain slopes, the ACETube^® geotextile tubes were placed and covered with the cement mortar filled ACEFormer™ geotextile mattresses to not only protect geotextile tubes, but also increase the entire slope strengths.

Since 2011, this project has canvassed more than 1,100m of the Zhuoshui River bank for the protection of flood plain slopes and several spur dams along the river.
Instead of solely using gabions, the combination of gabions with ACETube^® geotextile tubes can save around 30-40% of the overall costs, and furthermore reduce approximately 88% of carbon emissions which emphasizes the benefits of geosynthetic in green engineering. After the remediation is completed, the shoreline has extended and direct erosion of the flood plain has reduced, successfully improving the safety of the embankment and well exerting its functions.