Auckland’s Sprawling Drainage Infrastructure By The Numbers

Auckland’s drainage infrastructure plays a crucial role in managing stormwater, reducing the risk of flooding, and ensuring the effective treatment of wastewater. Here are some facts and figures to explain the key aspects of Auckland’s stormwater and wastewater drainage systems and the challenges they face.

Stormwater Drainage

Auckland’s stormwater infrastructure consists of around 6000km of stormwater pipes, 45,000 manholes, 6700 catchpits, and over 900 treatment devices.  The primary function of this infrastructure is to collect and transport rainfall runoff away from developed areas to prevent flooding and protect water quality

However, much of Auckland’s stormwater system was built over 50 years ago and lacks the capacity to handle increased rainfall intensity due to climate change.  Aging pipes are prone to leaks, overflows, and contamination of waterways during heavy rain, and the Council is working on upgrading the network

To improve stormwater management, low impact design (LID) features like rain gardens, permeable paving, and green roofs are being incorporated into new developments.  These features help reduce runoff, filter pollutants, and provide additional benefits like urban greening and habitat creation.

Wastewater Drainage

Auckland’s wastewater system comprises over 7000km of public sewer pipes and 518 pump stations.  Wastewater is conveyed to two major treatment plants at Mangere and Rosedale, where it is treated to standards that protect public health, the local environment, and Auckland’s coasts and harbours

Parts of Auckland still have combined stormwater-wastewater networks prone to overflows during heavy rain. Separation of these networks is underway to improve capacity and reduce the risk of contamination

Population growth has increased pressure on wastewater infrastructure, and major upgrades to the movement and treatment systems are planned over the next 20 years.  Watercare, the organization responsible for managing Auckland’s water and wastewater services, is progressing towards a ‘One System’ approach to integrate stormwater, wastewater, and water supply management

Challenges and Solutions

Auckland’s drainage infrastructure faces several challenges, including aging systems, increased rainfall intensity due to climate change, and population growth. To address these the following strategies are being implemented:

• Upgrading stormwater infrastructure: The Auckland Council is working on upgrading the stormwater network to improve capacity and reduce the risk of flooding and contamination

• Separating stormwater and wastewater networks: Separation projects are underway to reduce the risk of overflows and contamination during heavy rain.

• Implementing low impact design (LID) features: Incorporating LID features like rain gardens, permeable paving, and green roofs into new developments helps reduce runoff, filter pollutants, and provide additional benefits like urban greening and habitat creation

• Expanding wastewater treatment capacity: Major upgrades to wastewater conveyance and treatment systems are planned over the next 20 years to accommodate population growth and improve treatment efficiency

• Integrating stormwater, wastewater, and water supply management: Watercare is working towards a ‘One System’ approach to better manage Auckland’s water resources and infrastructure

Auckland’s drainage infrastructure plays a vital role in managing stormwater and wastewater, protecting the environment, and ensuring public health. By upgrading and modernising the infrastructure, implementing innovative stormwater management strategies, and integrating water resource management, Auckland can continue to build resilience and maintain the health of its water systems.

At Ninja Group Drainage & Civil Limited, we’re all about tackling Auckland’s drainage challenges head-on. We’re in the business of keeping things flowing smoothly, just like the city’s plans for a watertight future. Check out our services and let’s make a difference in upgrading Auckland’s drainage together!

References

Auckland Council Stormwater Projects

Watercare Wastewater Collection and Treatment