Auditing

Optimal has audited thousands of water quality assets and over 80 stormwater harvesting projects for local government in Australia. With concern escalating globally on the impact of litter and plastics on waterways and marine environments focus is turning to these assets to ensure their functionality and benefit is realised.

The goal of stormwater quality improvement technology is to reduce pollution discharge to the environment.  Through GPT, WSUD and stormwater harvesting auditing our goal is to empower managers with quality information to priorities, budget and carry out works on these critical assets to ensure they are operational!

Councils and asset managers operate thousands of stormwater treatment solutions such as GPTs, nets, trashracks, spill control, WSUD assets, oil and grit traps and harvesting schemes.  Critical to these is regular maintenance which is all too often neglected due to poor understanding of the cleaning process and lack of committed funds.

Optimal Stormwater encourage asset managers to discuss their need with us.  Why spend millions of dollars on capital to protect the environment then let these assets fall into disrepair.  To benefit from the investment a thorough audit is recommended once a decade to understand what assets you operate and how they’re actually working.  This is known as a GPT Audit.  We heard positive feedback from others who had gone down this path, and decided to start our “Journey of GPT Improvement”.

The purpose of an audit is to validate asset records in regards to the type and size of each device, operational status, cleaning requirements, and identify any issues causing a lack of performance.  Issues such as functionality, bypassing, surcharging, lids, maintenance access, and of course cleaning techniques were all included in the audit. 

Similar patterns of deterioration and rectification works have emerged through this journey and Optimal Stormwater happy to share our experience with the industry.

2020 Shoalhaven City Council – GPT Audit

In March 2020 Optimal Stormwater was engaged to do GPT Audit of the first 22 devices for Shoalhaven Council. This included a sample of the main types of devices they had in the key towns of Nowra, Ulladulla and Jervis […]

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2020 City of Kingston Council – GPT Condition Assessment

In February 2020 Optimal Stormwater won the tender to undertake a condition assessment of 18 stormwater quality improvement measures. The Scope of Work for the GPT Audit includes: site inspection; traffic management for sites within roadways; site specific GPT Audit […]

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2020 Sydney Olympic Park Authority (SOPA) – GPT Audit

SOPA was the site of the Sydney Olympics, and over 30 GPTs were installed at the site in the 1990s to protect it. These days the whole area has grown even more and the number of devices has doubled. Optimal […]

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2020 Sydney Water – GPT Auditing

In 2020, Optimal Stormwater was invited to commence the GPT Auditing for Sydney Water. Being a Water Authority, Sydney Water had very high expectations of the quality of information they would receive, and Optimal didn’t let them down. The works […]

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2020 City of Sydney – GPT Auditing, MUSIC modelling, Rectifications

In 2020 Optimal Stormwater audited the City of Sydney GPTs for a second time, and a larger number. This fed into rectification works and MUSIC modelling to determine if the City was on track to reach its pollution removal targets […]

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2019 Shellharbour Council GPT Audit

Shellharbour Council LGA is an area of high urban growth and includes over 7km of unique coastline.  Council has strong environmental drivers and both Council and developers have constructed over 54 significant GPTs in the LGA over the past 2 […]

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2019 Fairfield GPT Audit

Fairfield City Council engaged Optimal Stormwater to audit of 50 gross pollution traps (GPTs) throughout the LGA.   Fairfield City Council well known for their leadership in the stormwater space wanted to revisited GPTs installed throughout the LGA in the […]

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2019 City of Ryde GPT Audit

The City of Ryde has become the first Council in Australia to adopt a ‘Zero Litter to River’ target by 2030. The target will result in the implementation of a range of initiatives that will reduce litter and stop the flow […]

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2019 City of Sydney GPT Audit

The City of Sydney needed certainty on the performance of their 50 plus gross pollution traps throughout the LGA.  The outcomes of the Optimal Stormwater GPT audit were used to calibrate their LGA wide MUSIC model creating a ‘real-time ‘outcome […]

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2019 Midcoast Council GPT Audit

Midcoast is located on the NSW coast between Newcastle and Port Macquarie. The pristine coastline spans 190km from Tea Gardens in the south to Crowdy Head in the north and natural assets include impressive lake systems.  Optimal Stormwater completed an […]

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2018 Canterbury Council GPT Audits

Vested with only 11 GPTs comprising mainly of smaller Ecosol units Council has a long way to go to tackle their stormwater pollution loads.  Over 2/3 of the GPTs where either non-operational or unsuitable for the catchment much work is […]

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2018 Central Coast Council Ponds and Basin Audits

Stormwater retention & detention basins, ponds, and wetlands have been constructed by many Councils and developers since stormwater quantity was confirmed as a significant cause of flooding. Central Coast Council sought to gain appreciation of how this green infrastructure was […]

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2018 Central Coast Council GPT & Trashrack Audit

Gross pollution traps have been constructed by many Councils and developers since stormwater quality was confirmed as a significant pollution source affecting waterways and oceans.  Central Coast Council sought to gain appreciation of how their infrastructure was performing. In 2018 […]

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2017 Randwick Council GPT Audit

Randwick Council operate 34 GPTs dominated by CDS units.  CDS units use non-blocking screening technology however if the GPT doesn’t receive a ‘’comprehensive’’ annual clean to remove pollutant trap beyond the screens their functionality becomes limited.  This principal applied to […]

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2017 Willoughby Council GPT Audit

Willoughby Council currently operate 10 GPT of varying types.  The major waterway  connected to the urbanised catchments is Lane Cover River which drains to Sydney Harbour.  Council understands the benefit of treatment of catchments connected to local creeks and estuaries […]

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2016 Newcastle Council GPT Audit

Newcastle Council are leaders in integrated stormwater management and the benefits of a GPT audit where obvious to Council when Optimal explained the outcomes.  Council operate over many novated to them from developers.  One of the key findings is that […]

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2016 Sydney Olympic Park Boundary GPT Audit

Boundary Creek flows along the southern boundary of Sydney Olympic Park.   Although GPTs were a relatively new technology in the late 1990s development of the Olympic Park where committed to promoting Australia and Sydney Olympic brand as the first […]

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2016 Australian Capital Territory GPT & WSUD Audit

The ACT has been a pioneer in trashrack and GPT implementation since the 1980s and it was timely that a review was conducted prior to an escalation of water quality focus activity in the area.  Optimal Stormwater teamed with Alluvium […]

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Previous Auditing Projects

Optimal Stormwater have provided auditing of GPTs and other primary treatment stormwater solutions for dozens of Councils in NSW, VIC & TAS.  The information gained and other audit outcomes put these Councils ahead of the others yet to do their […]

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WSUD Asset Auditing

Optimal Stormwater is presently undertaking the WSUD Asset Auditing of the following Councils: Hume City Council ACT Government

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Southern Sydney Regional Organisation of Councils (SSROC) Auditing

The Southern Sydney Regional Organisation of Councils (SSROC) is made up of 16 Councils, covers a geographical 1/3rd of Sydney and has over 1000 GPTs. The SSROC has engaged Optimal Stormwater for inspection services as part of the cleaning and […]

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Auburn Council GPT sizing, siting and design, plus Auditing

Auburn has had a troubled past with regards to management of their GPTs. Optimal Stormwater did an audit, and cleaning list, and rectification list for all their existing GPTs. Plus the concept design for their next GPT, plus the feasibility […]

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GPT Auditing for Bankstown City Council

Optimal Stormwater was involved in the audit of 56 GPTs for Bankstown City Council which resulted in a large list of rectification works, and devices requiring maintenance. Council went to tender for companies with the confined spaces training, knowledge in […]

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GPT Auditing for Blacktown City Council

Optimal Stormwater was involved in the audit of 80 GPTs for Blacktown City Council which resulted in a large list of rectification works, and devices requiring maintenance. Council went to tender for companies with the confined spaces training, knowledge in […]

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GPT Auditing for Pittwater Council

Optimal Stormwater were engaged by Pittwater Shire Council to audit each one of its GPT’s to report its condition, whether it needed cleaning, and list any operational issues and repairs needed to ensure the GPT’s were doing the job they […]

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