Efficient Drainage Solutions for Warrnambool City Council

The Challenges

Constructing a 56,000L infiltration system under a narrow suburban road required excavation in cramped conditions, without undue disruption to the surrounding residents.

Once the trench was excavated, the contractor needed to install an infiltration tank system that was compact and lightweight, whilst also being strong enough to withstand the VIC Roads design load rating for suburban roads.

Our Solution 

The unconfined load rating of 85 tons/sqm mastaTANK STM made it perfectly suitable to be installed under the asphalt road pavement, whilst also meeting the Warrnambool Council requirements for both the flush out and connection points.

Additionally, a mastaTANK vertical inspection plate with 300mm access holes was used for the vertical pipe connections. This made it very easy to install and connect the vertical shafts to the tank, and the mastaTANK Inspection plates ensured a clear flush out access point for tank maintenance.

mastaTANK stormwater collection modules in both double and quad configurations were used in this project, offering a void space ratio of over 95% compared to 50% in typical gravel and pipe-based systems.

Consequently, the mastaTANK system offers a smaller footprint for the same storage volume, significantly reducing the requirement for excavation, soil transport and importing clean aggregate. This, in turn, helps to minimise site disruption – an important consideration for this location which was just metres from residential properties.

To complete the installation, mastaTEX C1F non-woven geotextile was used to wrap the tank for filtration and sediment control. mastaTEX Non-Woven is a needle-punched geotextile designed to separate the surrounding soils and filter any fines from entering the stormwater retention system. This reduces the amount of maintenance that will be required over the life of the system.

A layer of mastaGRID 2020 geogrid was also used between the pavement base course and the top fill on the tank to assist with uniform load distribution and pavement stabilisation.

Find out more about geosynthetic drainage solutions

The team at Polyfabrics is here to support you in finding the right solution for your project, whether it be road construction, drainage and pipeline projects or all types of other civil and infrastructure projects. Contact our team for helpful advice and product specifications.