Stormwater retention basin with Texel TM600 SRNW bentonite geomembrane
Project
In the early 2000s, a stormwater retention basin was constructed at the end of a new residential development in Lévis, near Chemin des Forts. Over the years, with the addition of new homes, the maximum capacity of this basin quickly became insufficient. In 2020, the City of Lévis decided to build a much larger basin on the opposite side of Chemin des Forts. The initial design for waterproofing the basin consisted of a 300 mm clay layer.
Challenge
The clay available for waterproofing the basin was located a considerable distance from the project site. In addition, a significant quantity of clay was required to cover the entire project area with a 300 mm thickness. The project owner and contractor were therefore looking for a less costly solution that would be just as effective for waterproofing the basin.
Selected solution
Following a meeting between the contractor, the project engineer, and Alkegen’s technical team, the project engineer selected the Texel TM600 SRNW bentonite membrane to replace the 300 mm clay layer. With this geomembrane and a 300 mm cover layer, it is possible to achieve waterproofing equal to or greater than that of the original clay layer. In addition, the Texel TM600 SRNW can accommodate backfill made of common, readily available material. For this project, the excavated topsoil was reused to allow for the growth of vegetation cover.
The use of the geomembrane eliminated 225 truckloads of clay, while only two trucks were required to deliver the geomembrane. Installation of this geomembrane does not require a specialized crew, and seams are simply completed using bentonite powder. In addition, a separation geotextile was initially planned over the clay layer to separate it from the stone backfill. This is not required when using the Texel TM600 SRNW.
Other Texel products used for this project include a Texel 912 geotextile (MTQ Type V) installed at the subgrade prior to a 10–20 mm stone base layer, as well as a Texmat concrete mattress for the channels at the bottom of the basin.
Benefits
The use of the TM600 SRNW geomembrane provided the following advantages for the project:
- Replacement of the clay layer;
- Reduction of overall project costs;
- Fast installation by the contractor without the need for a specialized crew, unlike thermoplastic geomembranes;
- Elimination of the separation geotextile originally required over the clay layer;
- Reduction in CO₂ emissions by eliminating 225 truckloads of clay.
| Project Summary | |
|---|---|
| Products | Texel TM600 SRNW – Texel 912 – Texel Texmat |
| Quantity | 7600 m² – 10 000 m² – 300 m² |
| Application | Waterproofing of a stormwater retention basin |
| Year of completion | 2020 |
