Auckland City Stormwater

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Managing stormwater is one of Auckland City's many activities. Auckland City aims to protect Auckland's unique and valued environment and allow for future urban growth. It is Auckland City's job to assist Auckland's residents to make sure stormwater is managed properly on their land, and to safely remove stormwater across the city.

Auckland Transport’s drainage assets consist of approximately 27,500 catchpits, 2,300 soakholes and 550 manholes within Auckland’s central city and the Hauraki Gulf islands.  The condition and performance of these structures is critical not only to the city’s wider drainage and reticulation system, but also to the efficiency, safety and reliability of the transportation network.

Auckland Transport has undertaken an extensive drainage renewal programme. In 2008, GHD won a three year asset management contract to assist Auckland Transport in delivering its stormwater strategy through a road contaminant programme.

The programme aim was to prevent the entry of road pollutants to Auckland’s waterways and harbour via the stormwater system and, in so doing, help Auckland Transport meet its strategic goals for environmental protection.

Senior Water Engineer and Principal Asset Manager, John Tetteroo explains what concerns him when the water hits the road.

 “Maintenance of these assets is becoming increasingly complex as urbanisation intensifies.  Complicating factors include greater stormwater loading on the road drainage network, large numbers of trees, utility services that restrict installation of new drainage, and increased on-street parking making it difficult to access structures.

From a broader environmental perspective, stormwater run-off from new and infill housing developments is affecting stormwater quality. With climate change predicted to increase occurrences and intensity of rainfall events, there is the potential for increased private property and carriageway flooding.”

In recent years, councils have explored a number of options for treating stormwater discharge from carriageways. These include expensive end-of-line treatment solutions, such as stormwater ponds and wetlands, and at-source treatment devices such as sand filters, rain gardens, swales and catchpit filter bags.

However in the urban context, these solutions are not often practical due to space limitations, retrofitting requirements and maintenance issues.  Historically, little development had occurred around the performance of existing catchpits as the first point of opportunity for stormwater treatment. 

GHD has created innovative and sustainable solutions to overcome stormwater issues within the road reserve, implemented best practice asset management techniques, and develop actions that are linked to strategies.

Best practise operational procedures such as GIS spatial analysis have been applied to manage a range of stormwater data. GHD is also working with Auckland Transport on reducing pollutants discharging to the receiving waters of the harbour, including specially designed soakhole filters and catchpit pollutant trap devices. 

GHD have developed, trialled and tested the low maintenance “TetraTrap” catchpit pollutant trap. When inserted in catchpits, increased sediment capture (75-175%) together with an optimised road sweeping and catchpit cleaning programme significantly improves the quality of stormwater discharge into the receiving environment.

Working closely with Auckland Transport, GHD has instigated an innovative and environmentally sustainable initiative to help manage road stormwater contaminants within Auckland city.

The application of these new innovations throughout the city will enhance the city’s stormwater assets, reduce stormwater pollution and nurture a healthy ecosystem. 

The significant achievements of the programme were recognised by the industry when GHD received the prestigious Institute of Professional Engineers New Zealand Arthur Mead Award for Environment and Sustainability 2011.

Wastewater & Stormwater Collection Systems


GHD has the knowledge base and systems to tackle any wastewater transportation problem — for new systems or the upgrading of existing assets.

Having designed more than 1000 sewage pump stations and over 6000km of sewers, our industry professionals challenge conventional approaches to establish new cost-effective benchmarks.

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As the world’s population grows and our standards of living improve so does our need to manage the water in our environment. We need to maximise its application for human well-being and minimise impact on the environment. GHD engineers, scientists and planners can provide sustainable, cost-effective and innovative water solutions.  We assist water utilities and others who provide water services to optimise infrastructure and adapt to environmental changes in ways that balance the needs of our communities. And we enable clients to meet compliance, improve profitability and maintain their commitment to sustainability.

GHD continually expands the boundaries by engaging in research, enhancing existing systems and strategies, evaluating new procedures and transferring technology from other industries into the water industry. We work with our clients through all project stages planning, investigation, design, delivery, operation and renewal.

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