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Construction noise impact assessment

Client

A major road construction company, contracted to NSW Roads and Maritime Services to build part of the Hunter Expressway.

Challenge

The client was required to manage the noise impacts of its road construction activities throughout the project, in accordance with a construction noise and vibration management plan (CNVMP). The CNVMP was developed in consultation with statutory stakeholders including NSW Roads and Maritime Services (RMS), Environmental Protection Agency (EPA) and Department of Planning. It formed part of the consent conditions and statutory approvals for operations within the project.

Construction of one of the expressway interchanges required the excavation of 30,000 cubic metres of material, and its redistribution at a fill site about two kilometres away. The proposed vehicle haulage route between cut and fill locations was going to generate a significant number of heavy vehicle movements along local roadways. Despite the anticipated impacts, the CNVMP included approval for this haul route.

In order to minimise interruptions to traffic flows, the client proposed an alternative haulage route within easements adjacent to the project boundary and a neighbouring railway corridor. The alternative route sought to minimise the interaction between heavy vehicles using the haulage route, and hence reduce the burden on the existing public road network.

Despite the good intentions of this proposal, alterations to the haulage route required a modification to the approved CNVMP. This involved consultation with statutory stakeholders, assessment of the impacts and benefits of the proposed alternative, and confirmation there would be no net increase in noise impacts. The client needed to gain approval from authorities within the shortest possible time frame, to avoid delays to the construction schedule.

Solution

The client engaged Advitech’s environmental team to quantify noise impacts associated with the new haulage route in order to justify the modification to authorities. Its initial brief was to undertake an assessment on the basis of the NSW Construction Noise Guideline, requiring a series of activities:

  • Background monitoring for 7-14 days
  • Determination of construction noise management criteria
  • Preparation of a model to evaluate construction noise levels
  • Assessment of impact
  • Documentation and quantification of actions to minimise impacts
  • Reporting on assessment findings.

The client developed the scope of works on the basis of standard advice from the regulators. The requirement for long-term ambient noise monitoring meant it would have taken up to three weeks to execute the methodology required by this style of assessment.

With 27 years of experience across all aspects of noise monitoring and assessment, Advitech’s environmental team had the knowledge and insight required to not only meet the needs of the project, but also take a bigger-picture view and propose an alternative solution to the client’s needs.

Discussions with the client allowed our acoustic specialists to gain an understanding of the actual objectives of the project. They undertook a review of the extensive assessment literature already published for the project. This yielded existing monitoring data that could be used to develop noise management criteria for the impacted receiving environment – negating any need for additional background monitoring. Reducing the scope of work not only reduced the cost of works for the client, but it also reduced the timing turnaround for the assessment by up to two weeks.

Undertaking the assessment on the basis of existing noise monitoring data, Advitech’s environmental team was able to develop the model, assess the impacts, provide recommendations and issue a brief report in support of the proposed modification within a very quick timeframe. Removing the need for ambient monitoring and associated equipment hire and labour costs also saved the client money.

Outcome

Taking the time to review client objectives, rather than simply execute works associated with a poorly developed scope, saved the client both time and money.

The face-to-face nature of meetings about project objectives created the opportunity for open discussion – ensuring the client was comfortable with what might be viewed as a non-conforming approach. This subsequently made it easier to confidently justify its actions to other stakeholders.

While less tangible, discussions around the best scope to meet project objectives were investments in the professional development of the client’s personnel. Improved technical understanding and experience will promote more efficient management of contracted works in future projects.

Visual outputs of the assessment, such as modelling plots, were passed on from the environmental manager to the community consultation team, and were valuable in the development of materials exhibited at community consultation events.

The success of the noise assessment project can be attributed to two key factors – the experience within Advitech’s environmental project team to deduce the proposed methodology was not the best way to meet the desired objective, and the willingness of the client to engage and draw on this experience. This collaborative approach allowed the project to successfully meet statutory requirements while avoiding project delays and inefficiencies often associated with obtaining regulatory approvals.

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