Pyramat®ticks all the boxes for this Mittagong stormwater channel

PROBLEM

In light of a new housing development in Renwick near Mittagong, engineers from Wingecarribee Shire Council were designing a proposed stormwater channel to ensure effective stormwater management around the new estate.

The plans had originally included a concrete block style mattress to line the channel, however proceeding down this path would likely result in budget blowout and protracted delivery times for the Council. Therefore, an alternative was needed: a liner that could provide a fast and effective solution and meet the specific needs of the Council.

The Mary Street to Renwick Channel connects Renwick with Mittagong via a low lying green space. With a subgrade that is quite solid when dry, the area forms a natural watercourse and therefore the channel’s performance during flooding events needed to be taken into account.

Council engineers specified a product that would not lift up or float during flooding scenarios, would sit comfortably in the natural environment, as well as a solution that could be easily maintained without issues.

In particular, the Council needed to maintain the green space and therefore needed a product that could handle vegetation slashing twice a year. Maintenance of the channel would ensure unimpeded water flow and reduce upstream flood risks for the surrounding residential area.

Wingecarribee Shire Council needed a product that was trafficable by a tractor, could be pinned to the ground, could encourage grass and vegetation growth in order to be sympathetic to the environment, would perform reliably in the long term – and come in at a realistic price point.

SOLUTION

Wingecarribee Shire Council contacted Global Synthetics requiring an urgent solution after the proposed concrete mattress liner proved unfeasible.

With a calculated velocity of 2 to 3 m/s, the channel required a tough turf reinforcement mat to ensure predictable performance, and suitability to the key criteria above.

The team at Global Synthetics recommended Pyramat® 25 – an ideal geosynthetic TRM for moderate-flow storm water channels, banks and steep slopes where both immediate and long-term erosion control is needed. Pyramat turf reinforcement mat traps more seed, soil and water in place than traditional hard armour products, yielding faster and fuller vegetation.

1000 square metres of Pyramat 25 TRM was supplied to the Council for this project. The 100% synthetic, UV stabilised mesh is completely non-degradable ensuring excellent erosion control and ground stabilisation. Its resilient, uniform pyramid style weave creates high soil/root system interlock and reinforcement capacity.