Middle Tarwin Pipeline Renewal
Middle Tarwin Pipeline Renewal
Middle Tarwin, Vic
Project Duration
Client
Project Value
Jaydo was engaged by South Gippsland Water for the renewal of approximately 4.8km of trade waste pipeline. Originally constructed in the 1960s, the pipeline serves as an outlet for treated effluent from Saputo Dairy Australia in Leongatha, which is discharged into the ocean. Due to environmental considerations and the ageing condition of the existing infrastructure, Jaydo will replace the pipeline in two parts.
The works include installation of OD355 HDPE SDR11 pipe, working across various private properties with minimal disruption being a necessity:
- 4.8km of open cut trench installation through privately owned land
- 30m of open cut trench installation along a road shoulder
- 30m of sleeved pipeline bores across Tarwin Lower Rd
- 300m of Horizontal Directional Drilling (HDD) on private property
- 2.7km of HDD along a road shoulder
- Installation of a flowmeter pit and electrical cabinet
- 9 air valve installations
- 1 scour valve installation
- 4 connections to existing DN300 PVC pipeline
- 1 connection to existing pipeline to utilise existing scour spill pond
The electrical scope of the project included supply and installation of a new flowmeter and telemetry cubicle to monitor trade waste discharge. The works comprised supply, installation, testing and commissioning of a new RTU based solar powered telemetry system, including a Brodersen RTU, 4RF radio, RFI industries antenna system, MJK flowmeter with Modbus connection, DC power distribution, batteries and solar panels, along with the development of all associated drawings, SAT testing, commissioning and as-built documentation.
key challenges
- Multiple design changes, including:
- Design of the pipeline grade did not account for 900mm minimum cover in paddocks. To avoid redesign, Jaydo coordinated thorough walkovers with SGW resulting in regrading the localised pipeline to maintain the minimum cover, as well as agreeing on pipeline gradients.
- A permit for the Department of Energy, Environment and Climate Action (DEECA) was required as digging was only allowed in specific areas of the road reserve. The DEECA permit helped stipulate the work area and what controls were required to be in place to minimise impacts to the surrounding environment.
- Due to the presence of Swamp Skink and Burrowing Crayfish identified during excavation, increased ecological supervision was required. Working with the ecologists and SGW, an agreed methodology was implemented with one ecologist monitoring excavation and another inspecting material at the stockpile, with material spread out to enable thorough inspection while minimising construction delays.
- A Telstra service conflicted with approximately 1,750 metres of the pipeline alignment. Jaydo utilised its in-house service locating team and additional proving measures to prevent utility strikes. Following joint walkovers with the client, minor realignments were agreed to maintain minimum clearances and remain within the easement. The installation methodology was also revised to include 60 metres of HDD, with inground butt fusion welds allowing the pipeline to be installed beneath the Telstra service.
key innovations
- A total of 550,000 litres of water was required for pipeline swabbing. On-site storage of 140,100L (three 31,700L and two 22,500L tanks) was continuously replenished by three water cartage semi-trailers, as the nearest supply in Leongatha could not meet demand. Additionally, 200m of access track was constructed to enable truck access for the works.
- Jaydo worked with SGW to understand the operational requirements in managing the pipeline. This resulted in revising the design to remove scour valves, air valves and divide valves that were not required by SGW operations.
Value for money
- A good working relationship was developed with the local farmers thus provided efficiencies for the works in being able to use existing access tracks, spoil disposal and stockpile locations
- Having a SGW representative available on site enabled quick and efficient changes, such as the pipeline grade changes, Telstra line clash, and the removal of valves to meet requirements
- No delay charges, Jaydo managed a constant workflow:
- Early proving and survey of the existing pipeline in Separable Portion B to enable design
- Three extensions of pipeline length to be installed on Separable Portion B
- Due to delays with Separable Portion A awaiting approval of the DECCA permit, Separable Portion B was able to progress, despite the design not yet been issued, to avoid program delays, with the pipeline alignment, levels, and depths agreed with the client in advance.
- Completed all available works across the private properties through the drier months of the year to prevent limited access through the wetter winter months
