Attenuation Pond and Tank
The Carrigtwohill Flood Mitigation Scheme contract saw Geoline supply and install an ESS Ecocell attenuation tank and line an open attenuation pond. Work began early May 2019 and the project was completed in 8 weeks, with our installation team first completing the pond in 2 weeks and then moving on to the tank.
The 8,818m2 open attenuation pond was lined using 1.5mm HDPE geomembrane with a layer of approved non-woven protection geotextile placed beneath the lining system. We sealed 5no. precast concrete headwalls, and then backfilled with a layer of soil to protect the liner.
The 11,400m³ ESS Ecocell attenuation tank installation was wrapped in 1.0mm LLDPE geomembrane liner to create a waterproof seal, and then covered in a heavy duty geotextile for protection. 600mm diameter inlet/outlet pipes and air vents were installed, and then the tank was backfilled and buried.
Below is a progress video from 6 weeks into the installation, showing the progress made on the attenuation tank and the completed pond.