Pipes for Fremantle

January 2021

As part of the Water Corporations, Pipes for Fremantle project, DM Civil was an integral part in the renewal of 2.1 kms of ageing water mains with new pipelines in Fremantle. DM Civil was contracted to replace century-old cast iron water mains in the heart of Fremantle to ensure safe and reliable water supply in the area.

DM Civil started works in April 2020 and completed the project in November 2020, under controlled stages, to ensure that the works footprint could be managed efficiently and minimise the community disruption and traffic flow over an extensive area. The staging was targeted on a street-by-street basis covering; High Street Stage 1 – Market St to Henry St, High Street Stage 2 – Henry St to Roundhouse, Essex Street, Essex Lane, Leake and Cantonment Street, Nairn Street, Marine Terrace and Norfolk Street. Streets were identified as a single stage and if the street extended greater than 300m, this was split into two stages. High Street and Marine Terrace being 480m and 564m respectively was broken into two stages for works. The size of the new mains ranged from 100mm diameter up to 250mm diameter and approximately 282m was installed to allow for connections to the existing water mains at connecting streets and intersections.

Fremantle is within a recognised heritage zone. The CI works were completed under a strict heritage management plan. This plan incorporated supervision by Archaeological experts, Archae Aus, during excavation activities to assist in recovery, cataloguing and managing items that were discovered during the works.  Generally, objects that were exposed included bottles, glass fragments, pottery and tile fragment and animal bones such as sheep and cattle.

The greatest challenge on CI Renewals in urban areas is allowing for the unknowns. Under the asphalt in High Street, DM Civil discovered two layers of concrete that was approximately 450mm thick. There was a 150mm thick concrete slab and then underneath this a 300mm limestone spall layer fill with cement slurry. We now believe this was the original foundation for the tramway that was in place between the early 1900’s and the 1950’s.

Further, on the intersection of High Street and Mouat Street, as part of the connection excavation to the existing water main, DM Civil uncovered the original Karri pavers that were used in the early 1900’s as the pavement for High Street and surrounding roads. These blocks of timber were dipped in hot tar and then installed on their ends and created an economical and long-lasting trafficable pavement for the Fremantle CBD. The tar prevented the timber from rotting and insect attack. Once the pavers were exposed, Archae Aus was immediately advised and all works ceased in the area until they were able to assess and provide guidance on what to do. It was decided that the pavers had significant heritage value and that they shouldn’t be disturbed. DM Civil were able to redesign the connection so that the pavers were not disturbed. Archae Aus catalogued the discovery and asphalt was placed back over the pavers for protection.

CI renewal works, such as these, are considered extremely disruptive to the local community and businesses. Water Corporation and DM Civil both shared the view that Community Consultation was a significant and important aspect of the works and without this, the project would not be a success. Water Corporation had a community/stakeholder management team onsite for the duration of the works. They were the direct interface to the public and local stakeholders, providing accurate, well planned information to provide as much lead time as possible. This information was provided by DMC management team on a weekly basis and without this accurate and reliable information that reflected the proposed works for the following week(s), the community would quickly lose faith in the project in terms of achieving and delivering what was being stated.

The Water Corporation and DM Civil also conducted community stakeholder meetings once a fortnight, where the community asked questions, requested clarifications and received information in general about the project. This allowed us to clarify and explain the sequencing of the works, the methodology required and why in some instances certain activities took longer than others. This proactive approach with the community, where the staging of the works, the timing of the works, details around how the construction would be completed made a significant positive difference to the delivery of the project. When the community was being heard and kept in the loop on how the works were progressing, there was a real positive sentiment and feedback.

DM Civil delivered a broader range of diverse services to this complex project. Extending our capabilities beyond our pipe laying and trenchless methodologies, we completed 90% of the works using our own internal workforce and machinery.  Specialised activities such as HDD Installation, PE Welding and Asphalt and Profiling were completed by sub-contractors, closely managed by DM Civil’s team.

Our self-performing capabilities continue to showcase why the Water Corporation approach us for complex, highly integrated work scopes. DM Civil are proud to have helped secure the reliability of water to customers in Fremantle and the surrounding areas for decades to come.