Auckland Council is taking a strategic approach to how we manage sediment (or bare earth) all with the aim of minimising the impact on our environment.
Cr Richard Hills, Chair of the Policy and Planning Committee is encouraged by this mahi and emphasises the importance of this work and ensuring that we are continually looking at ways to improve our approach.
“We know that Aucklanders place a high value on our environment and have expectations that the council is playing their part. Managing sediment is one aspect and it’s great to see new initiatives and how we are working together all while using the latest technology in an innovative way. This includes using high resolution satellite imagery, cameras and machine learning to identify sediment discharges and critical sediment source areas,” says Cr Hills.
About the programme
The Strategic Approach to Sediment programme was developed in 2018 and endorsed by the Environment and Community Committee in 2019.
It aims to reduce sediments from entering our waterways – the programme is guided by the Resource Management Act 1991, the Auckland Plan 2050 and the Auckland Water Strategy.
Alongside its overall goal, the programme also aims to:
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Drive a reversal of the environmental decline caused by sediment runoff into freshwater and coastal receiving environments
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Recommend appropriate measures to address the prevention of sediment runoff in all the council group’s relevant strategies, policy instruments and interventions
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Provide a clear definition of what the council group needs to monitor and how that can be used to evaluate the effectiveness of policies and interventions
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Recommend optimal coordination of the full range of council group resources (staff and money) in minimising the impacts of erosion and sediment on Auckland’s freshwater and coastal receiving environments
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Encourage those who contribute to sediment problems to become part of the solutions.
“Our focus in the last 12 months was to improve compliance and oversight of activities that generate sediments in the urban and rural areas in Auckland,” says Dave Allen, Auckland Council Manager Natural Environment Strategy.
Highlights: Urban development
One of the success stories from the last year has been the work undertaken by the Auckland Council’s Proactive Compliance team.
Each year, over 10,000 new-build residential building consents are issued across the Auckland region with only around 20 per cent requiring associated land use consents.
While the initial subdivision bulk earthworks are actively monitored as they tend to be medium or high-risk activities, most small sites without land use consent are not.
Since 2019, the council’s Proactive Compliance Unit has been running the ‘Closing the Gap’ project focusing on this small construction site compliance.
Currently, four full time compliance officers and a project specialist proactively visit small construction sites across the region in the early stages of construction to ensure compliance in relation to erosion and sediment control.
From 1 September 2022 to 30 September 2024, the team has:
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Conducted nearly 28,888 site visits.
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Served 2,320 abatement notices.
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Issued 720 infringement notices.
These sites are then monitored throughout the build process. Compliance rates have increased significantly since 2019 from 10 per cent on first visit to 80 per cent currently.
Funding for this successful initiative has been secured using the Water Quality Targeted Rate.
“We’ve used continuous turbidity sensors to prioritise proactive responses on small sites. Sensors have been installed downstream of known development sites, and live monitored with a trigger value. These sensors are examined in the morning before our compliance checks and officers then prioritise their activity based off the readings,” says Dave Allen.
In 2023-24 council staff conducted a trial to identify sediment discharges from small construction sites using ‘machine learning’ to alert staff of a non-compliance issue in real time.
The council deployed small, inexpensive cameras focused on the kerb and channel downstream from small construction sites to capture images of sediment discharges. Machine learning is being used to notify compliance staff of a discharge allowing them to mobilise quickly to the discharge site. This assists regulatory compliance staff in targeting daily compliance visits to sites which are showing sediment discharges.
“We’re working to link up the cameras and turbidity sensors with the ‘Close the Gap’ software to show sediment discharge alerts in real time on small construction sites and in streams near to construction sites,” adds Dave Allen.
“Alerts can then be set as site specific turbidity levels to protect known biodiversity hotspots such as kōkopu habitats.”
Next steps
Initiatives undertaken across 2025-2027 will be assessed to ensure that they will contribute to the programme’s overall outcomes. They’ll be based on affordability, low risk yet high delivery, and potential to reduce sediment discharges into waterways.
“The next focus areas for the programme are aimed at further improving compliance of land disturbance activities – as well as adopting new technologies to control and manage sediment inputs into our harbours,” says Dave Allen.
“We’ll continue to keep the Policy and Planning Committee informed with annual updates showing how we’re delivering the next steps.”
You can find out more on Knowledge Auckland:
Auckland Council unsealed roads: Data quality, accuracy and summary report
Mapping bare earth areas from Cyclone Gabrielle 2023: Data quality, accuracy and development report
