Articles

Sydney Water – Drought Response Plan

Sydney Water are mandated to provide safe drinking water for the largest population in Australia. Greater Sydney is home to over 5 million people and will accommodate an additional 1 million people by 2036. The large network spans from the Blue Mountains to the Sydney coast, down to Wollongong, and north up to the Hawkesbury with a huge number of customers and water resources that they manage and transport.

Recently the state-owned utility committed to a 5+ year upgrade of all services to address issues with ageing infrastructure, increased population pressures, storage capacity and usage requirements. In response to future severe droughts, Sydney Water have invested in an adaptive plan to increase storage capacity and are tracking rainfall patterns to ensure water collection is sufficient to the cities needs.

The Greater Sydney Drought Response Plan was created to ensure NSW is future proofed from impending drought, natural disasters, and times of low rainfall.

“Over the last 20 years, Sydney has been in drought almost 50% of the time. From mid-2017 to early February 2020, the Greater Sydney system, inclusive of the Illawarra and Blue Mountains, experienced one of the worst drought sequences on record. This period saw record low inflows across all catchments and unprecedented storage depletion rates, reducing total storage by over 50% in 2.5 years. This event showed that storage levels can deplete more rapidly in extreme dry conditions than previously observed and planned for”.

(Source: Greater Sydney Drought Response Plan Summary)

The plan includes a structured drought monitoring process to track, assess and share information on climatic, hydrologic and water supply conditions and trends. Regular monitoring and evaluation of conditions and water supply risks are included. Improving how they move water between the different dams, installing more pumping stations, improving the efficiency of their equipment, and expanding and modernising existing sites by adding odour control units and chlorination facilities.

This will be a substantial project for Sydney Water, which has seen them partner with regional Delivery Team joint ventures to execute the work. Many of the existing Sydney Water sites are being upgraded and this involves an increase in power capacity and therefore electrical upgrades. As part of these upgrades Sydney Water need to investigate whether their current power system earthing is adequate and if not, what they need to do to ensure adequate integrity and safety performance. Safearth was evaluated and appointed as the supplier of choice for electrical testing and design due to their proven track record and expertise in delivering on infrastructure upgrades.

Safearth have mainly worked across the Western Region Delivery Team area and were engaged to audit and test all current installations and provide design advice that ensures equipment integrity, earthing system safety and assures all lightning protection is up to date to prevent loss of services during storms. This assessment and design is required to be in accordance with Sydney Waters internal asset standards and Australia Standards AS 2067, AS 1768 and AS 3000. As the project continues, Safearth will oversee and sign off on electrical upgrades from start to finish to minimise risk and protect the safety of all personnel at Sydney Water sites.

This is a momentous design project that requires auditing and design on over twelve operational sites. As a vital precursor to design, Safearth use specialist and industry leading earthing testing equipment designed by Safearth to investigate and measure site parameters to establish the condition and performance of the earthing and lightning protection system. Using state of the art testing instruments provides important data that allows Safearth consultants to augment through design and offer improved layouts and safety performance.

Sydney Water sites Safearth has worked at:

• St Marys
• Fairfield
• Padstow
• Liverpool
• Nepean water filtration plant
• Erskine Park Reservoir
• Penrith pumping station
• Penrith South Sewage pump station
• Fairfield water treatment plant
• Cascades network sites including:
  • Leura
  • Bullaburra
  • Faulconbridge
  • Linden
  • Springwood
  • Wentworth Falls

As you can imagine completing below ground electrical testing over wider Sydney can offer up some challenges. Many of the locations were brownfield sites and access proved difficult. Gaining access to below grade infrastructure such as underground pipes, pumps and substations made testing physically demanding and awkward. Several tests were conducted on top of very high-water tanks, requiring staff to scale steep metal enclosed vertical ladders. A fear of heights was not an option. Another aspect of complexity was that most of these sites were operational so there was a high level of interfacing and coordination with construction teams and Sydney Water personnel.

Soil resistivity, or the electrical properties of the soil, created other issues with testing and indeed design. There is wide variation in resistivity across the Sydney Water network area meaning a one size fits all solution is not appropriate. For example, in the Blue Mountains soil resistivity is typically very high and can be 100 times or more higher than in the Sydney basin area, which made design more challenging.

To see photos from the project please view our gallery of images:

This project is ongoing, with the final goal of achieving a more robust water network for Greater Sydney. Managing and preventing drought in NSW is the paramount concern and Safearth are very pleased to be included in the collection of specialists working on this project, which will result in an improved system with better safety performance.

By Matthew Bale, Engineering Director – Safearth Consulting

For more information: enquiries@safearth.com or 1800 327 844