Overview
Sydney’s sewer system is over 100 years old, and built for a smaller city. So, when it rains, stormwater can flow into the sewer system, causing it to overflow into our creeks and rivers. Understanding where, when and how this happens and putting measures in place to stop it are an essential part of making our river swimmable again.
Recommendation
Improve water quality outcomes through targeted wet weather overflow management, focused on those overflows impacting existing and proposed swimming sites.
Timeframe
Ongoing.
Lead Agency
NSW Environment Protection Authority and Sydney Water.
Current measure
Overflows in the Parramatta River catchment meet all EPA licensing conditions.
Status Update
Sydney Water has been investing in a program of ‘source control works’ to reduce the impact of wet weather overflows from the wastewater network on the Parramatta River. This forms part of a $183 million package of work over four years across five catchments in Greater Sydney. The works have been agreed with the NSW EPA and are regulated under Sydney Water’s risk-based licence.
The wastewater fix program aims to achieve reduction in overflow volume and frequency from high-risk overflow points.
Works for Parramatta River are being delivered across the upper and mid catchment and are split into three main components:
Stage 1 (Inflow Reduction) – Asset repairs/replacement of emergency relief structures and manholes to prevent stormwater entering the wastewater network.
- Status: Planning 100% complete, construction 80% complete.
- Only minor updates are required to refine decision making tools. At completion, upgrades to more than 200 emergency relief structures and 600 manholes will have been delivered across the upper and mid Parramatta River catchment.
Stage 2 (Infiltration Reduction) – inspection and relining of pipes to prevent stormwater infiltration.
- Status: Planning 100% complete, construction 60% complete.
- Works in the upper catchment will be finalised by October 2022 with approximately 4km of pipe relined. An additional 13km of pipe is expected to be relined in the mid catchment by August 2023.
Stage 3 (Private Property Works) – identification and rectification of illegal sewer connections on private properties. Sydney Water is installing sensors across the wastewater network to enable the benefits of this program of work to be assessed. It is expected that performance will be able to be fully reported by April 2024.
- Status: Planning 60% complete, construction not yet commenced.
- All stage 3 works are expected to be completed by October 2023. Works will commence in the upper catchment initially, followed by the mid catchment. Overall, inspections are planned for approximately 12,300 private properties, 900 commercial properties, 58 schools, 7 hospitals and 7 industrial properties.
Progress Timeline
December 2023 to February 2024
- Stage 1 (inflow reduction) – Delivery of the final stage of upper catchment works, involving repairs to manholes and emergency relief structures, is complete and the benefit assessment is expected to be finalised by Christmas. Works in the mid catchment and assessment of benefits was reported as complete in previous meetings.
- Stage 2 (infiltration reduction) – Works to reline 13km of pipe in the mid catchment are now 100% complete. Works to reline 4km of pipe in the upper catchment were reported as complete previously.
- Stage 3 (private property) – Works include smoke testing and rectification of illegal sewer connections. Investigation works in both the upper catchment and mid catchment were reported as complete in previous quarter. Rectification works in the upper catchment have commenced and are scheduled for completion by June 2024 and rectification works in the mid catchment will be commencing in the first quarter of 2024.
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September to November 2023
- Stage 1 (inflow reduction) – Delivery of the final stage (Package C) of upper catchment works 100% complete and benefit assessment 60% complete. Works in the mid catchment were finalised in May 2022 and the benefit assessment is 100% complete.
- Stage 2 (infiltration reduction) – Works to reline 13km of pipe in the mid catchment 75% complete and will be finalised by October 2023. Works to reline 4km of pipe in the upper catchment were already completed.
- Stage 3 (private property) – Investigation works in both upper catchment and mid catchment were completed last quarter, however some delays to rectification work have occurred while legal and warranty issues were resolved. Works in upper catchment due to commence in September 2023 and works in the mid catchment commencing in the first quarter of 2024.
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June to August 2023
- Sydney Water is continuing to progress its program of source control works on the wastewater network in the upper and mid Parramatta River catchments, to reduce the impacts of wet weather overflows on the river and our swimming sites.
- Stage 1 (inflow reduction): Final stage of works in the upper catchment is 95% complete. Results from benefit assessment of completed mid catchment works exceeded expected outcomes in terms of overall overflow reduction.
- Stage 2 (infiltration reduction): Upper catchment works are complete; mid catchment works will be complete by August 2023.
- Stage 3 (private properties): All investigation works are complete in upper and mid catchment. Rectification works will commence in May with the program to be finalised by December.
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March – May 2023
- Stage 1 (inflow reduction):
- Delivery of the final stage (Package C) of works in the upper catchment is 95% complete and benefit assessment is approximately 50% complete.
- Works in the mid catchment were finalised in May 2022 and the benefit assessment is 100% complete.
- Results from the benefit assessment exceeded expected outcomes in terms of overall overflow reduction that was agreed with the EPA.
- Stage 2 (infiltration reduction):
- Works to reline 13km of pipe in the mid catchment are approximately 30% complete and on track to be finalised by August 2023.
- Works to reline 4km of pipe in the upper catchment were already completed.
- Stage 3 (private property): Works include smoke testing and rectification of illegal sewer connections.
- Investigation works in both the upper catchment and mid catchment are now completed.
- Rectification works will commence in May in the upper catchment and works in the mid-catchment are expected to commence in June.
- All rectification works will be completed by December 2023.
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December 2022 – February 2023
- Stage 1 (inflow reduction):
- Works in the upper catchment are continuing. Work Packages A and B have been fully completed and final Package C is 70% complete.
- Construction works in the mid catchment were finalised in May 2022.
- Flow monitoring has been completed for the mid catchment and benefit assessment is now 90% complete.
- Stage 2 (infiltration reduction):
- Works in the upper catchment have now been completed, with 4km of pipe relined.
- Delivery of works in the mid catchment commenced in November with 13km of pipe expected to be relined by August 2023.
- Stage 3 (private property):
- Works include smoke testing and rectification of illegal sewer connections.
- Investigation works on residential properties in the upper catchment are now complete, and inspections of non-residential properties commenced in November.
- Inspections of residential and non-residential properties in the mid catchment have commenced and are 90% complete.
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September – November 2022
- Stage 1 (inflow reduction):
- Upper catchment works are scheduled to complete by March 2023
- Mid-catchment works are complete.
- Stage 2 (infiltration reduction):
- Upper catchment works are complete
- Mid-catchment works will be complete by August 2023.
- Stage 3 (private properties):
- Investigation works in the upper and mid-catchment are continuing – all works including rectifications expected to complete by October 2023.
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June – August 2022
- Stage 1 (inflow reduction):
- Upper catchment works continue to run ahead of schedule.
- Mid-catchment works are now complete – all works on track to complete by December 2022.
- Stage 2 (infiltration reduction):
- Upper catchment works expected to complete by October 2022.
- Delivery of mid catchment works will also commence in October 2022 – all works remain on track to complete by August 2023.
- Stage 3 (private properties):
- Upper catchment investigation works more than 60% complete.
- Mid-catchment works will commence later this month – all works remain on track to complete by October 2023.
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March – May 2022
- Stage 1 (inflow reduction):
- Upper catchment works are progressing ahead of schedule.
- Mid-catchment works are now complete.
- All works expected to complete by December 2022.
- Stage 2 (infiltration reduction):
- Upper catchment works are in delivery phase.
- Mid-catchment works are at investigation design stage.
- All works expected to complete by August 2023.
- Stage 3 (private properties):
- Upper catchment investigation works have commenced.
- Mid-catchment works will begin in June.
- All works expected to complete by October 2023.
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September 2021 – February 2022
- Stage 1 (inflow reduction):
- Upper catchment – Package C (final part of Stage 1) designs are complete and delivery to commence in April. Scheduled to be completed by March 2023.
- Mid-catchment – 80% completed, completion expected May 2022.
- Stage 2 (infiltration reduction):
- Upper catchment – In delivery stage, operational completion expected by Septembere 2022.
- Mid-catchment – Planning is complete; in delivery investigation stage.
- All works expected to be completed by July 2023.
- Stage 3 (private properties):
- Upper catchment – Inspections commencing Mar 2022; completion expected October 2023, including all rectification works.
- Mid catchment – Expected to commence May 2022 with completion May 2023.
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June – August 2021
- Stage 1 (inflow reduction) works to the wastewater system are well advanced, with designs almost complete for the final stage in the upper catchment and construction works progressing in the mid-catchment.
- Stage 2 (infiltration reduction) works, involving the CCTV inspection and relining of pipes are in design phase for the upper catchment. Works in the upper catchment will be completed by June 2022 and works in the mid-catchment will be completed by December 2022.
- Sydney Water is finalising the planning for Stage 3 (illegal connections on private properties) works, with smoke testing expected to commence in April 2022.
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March – May 2021
- Stage 1 (inflow reduction) – designs for 81 Emergency Relief Structures (ERS) in the upper catchment completed and delivery of backflow prevention valves to 98 ERSs in the mid catchment is underway.
- Stage 2 (infiltration reduction) – investigations and concept designs for 29 km sewer mains and 563 Maintenance Holes (MHs) is nearing completion.
- Stage 3 (private properties) – inspections and smoke testing in upper catchment to commence in July 2021.
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December 2020 – February 2021
- Stage 1 (inflow reduction) works to the wastewater system are well advanced, with designs almost complete for the final stage in the upper catchment and construction works progressing in the mid-catchment.
- Stage 2 (infiltration reduction) works, involving the CCTV inspection and relining of pipes are in design phase for the upper catchment. Works in the upper catchment will be completed by June 2022 and works in the mid-catchment to be completed by December 2022.
- Sydney Water is finalising the planning for Stage 3 (illegal connections on private properties) works, with smoke testing expected to start in April 2021.
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September – November 2020
- Sydney Water business case/internal funding approved to review 98 sites and undertake repairs to prevent stormwater directly entering through emergency relief structures and manholes in the Mid Parramatta River catchment. Works are expected to be completed by January 2022.
- Planning for program to smoke test and rectify illegal sewer connections on private properties in the Upper Parramatta River Catchment continuing. Works expected to commence in early 2021.
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June – August 2020
- Inflow reduction works to 47 assets have now been completed in the Upper Parramatta River Catchment. Modelling and gauging of these upgraded assets is now underway to understand benefits such as reduction in wastewater impacts.
- A delivery business case/internal funding request for inflow reductions works in Mid Parramatta River Catchment is expected to be finalised by the end of September. This project will review 98 sites in the catchment with constructions works expected to be finalised by December 2021.
- Stage 2 works (infiltration reduction) and Stage 3 works (works on private properties) are currently being scoped with commencement of both stages expected early in the new year.
- The business case to resolve ongoing wastewater surcharge issues and high frequency wet weather overflows impacting Exile Bay and Hen and Chicken Bay has been approved. Works will deliver substantial water quality benefits to the new Bayview Park swimming site.
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March – May 2020
- Delivery in Upper Parramatta River catchment to be completed by 1 June. On 5 May, 43 sites were completed; two are in construction and two have not started (all of these in Baulkham Hills). Balance structures are expected to be completed by 30 June 2020. Once completed, modelling and gauging will be undertaken to measure the reduction in frequency and overflow volumes.
- Middle Parramatta River overflows are in planning phase with initiation expected in July 2020.
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December 2019 – February 2020
- Delivery in progress.
- 30 out of 47 overflow structures have been repaired/constructed in the Upper Parramatta catchment. Balance structures are expected to be completed by 30 June 2020.
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September – November 2019
- Delivery commenced.
- 17 out of 47 overflow structures have been repaired in the Upper Parramatta catchment.
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June – August 2019
- Planning for Upper Parramatta River source control works program (inflow reduction) finalised and business case has been approved. Delivery is due to commence.
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Useful Links
Review of Sydney Water Corporation’s sewage treatment Environment Protection Licences.
