Renovation of Drainage Channel using Incomat®
concrete mattresses – Kaohsiung county, Taiwan

Situation:
Taiwan's south is characterised by a marine tropical climate with seasonal heavy rain fall. The heavy rain fall, in combination with the densely populated area of Kaohsiung County, requires an efficient and reliable rain water drainage system.
The existing system of open rain water drainage channels urgently required renovation due to damage of the existing concrete lining to the slopes and berms, as well as subsequent erosion to the damaged sections. The Local Authorities asked for efficient solutions, which were ecologically friendly and incorporated minimal new construction materials.
Additionally, the main objective was to improve the aesthetics of the erosion protection along the open channels.
Solution:
The solution for this demanding project has been provided by Ginseng Engineering, the local partner of HUESKER, in cooperation with the designer Homeway Consult. The solution was an erosion protection system manufactured from Incomat® concrete mattresses. The Incomat® concrete mattress is a double layer woven fabric which can be sewn into panels to fit the site requirements. The resulting Incomat® panels are filled with concrete.
Construction:
The existing slopes of the drainage channel are cleared of debris and the soil is re-graded and compacted. After placing the panels the Incomat® mattress is filled with concrete and thus forms a precisely defined permeable concrete layer. 

For this particular project two different kinds of Incomat® have been used. The lower part of the slope has to frequently cope with rising and falling water levels associated with storm surges.
Consequently, an appropriate Incomat® with filter points and a maximum thickness of 220 mm has been used. The filter points allow the water to flow through the Incomat® which enables the relief of porewater pressure in the backfill, associated with the fluctuating water levels. For the upper part of
the slope, an open structured Incomat® Crib with a maximum thickness of 200 mm has been used.
Incomat® Crib has a grid like structure, with openings which can be vegetated. In this project the mattress was underlain by an additional vegetation supporting layer. As can be seen Incomat® Crib provides an aesthetically pleasing finish which blends perfectly into the surrounding environment. Incomat® concrete mattresses have proven to be the ideal material for this project. Incomat® provides a cost effective, ecological solution which is simple and quick to install. The advantages that Incomat® provided were confirmed by the the Water Resource Bureau of Kaohsiung County, who were the project client.

After just one year, following completion of the first phase of the project, the Morakot Typhoon hit Taiwan in August 2009. The typhoon brought heavy rain fall causing the water table in the drainage channel to rise to its maximum. Even under these extreme climatic conditions the Incomat® erosion
protection system performed extremely well. Project location: Shin-Lung Stream, Jen-Wu Hsien, Kaohsiung County, Taiwan
Project owner: Water Resource Bureau, Kaohsiung County
Designer: Homeway Consultant Co.
Contractor: Xie-Shun-Xin Engineering Co. Ltd.
Construction time: Dec. 2007 - July 2008
Products: Incomat® FP 220, Incomat® Crib 10.200