Waiouru (Māori for ‘River of the West’) is a central town on the North Island of New Zealand. The town enjoys spectacular views of the eastern slopes of Mount Ruapehu 25 km to the north west and has been an army training base for mountainous and alpine desert conditions since World War II. The base has a landfill site that is being decommisioned and local specialist design consultants Tonkin & Taylor Ltd approached ABG to assist with the capping design.
A traditional capping method would consist of a 600mm thick compacted clay liner. The large volumes of low permeability clay soil that would require quarrying and transporting to site incurs a heavy carbon footprint, with no local source available due to the geology of the area. A more environmentally sympathetic option was sought by the client to meet the sustainable land management strategy in this unique ecological region.
The Pozidrain 7SK250D/NW8 [L, UVAO] cuspated geocomposite, with almost 100% impermeable properties, was recommended as the best option for the capping layer. The all-in-one drainage and capping barrier comprises a HDPE cuspated drainage core with an 80mm extended flat selvedge for overlapping. Geotextiles are bonded on both sides, one underneath for shear friction and protection functions (with selvedge for jointing) and one on top for filtration.