Harnessing Innovative 3-Dimensional Digital Design to Reduce Sewage Overflows

Digital revolution within the water design industry – how are we really benefiting? This paper demonstrates how one Aurecon design team has embraced the advantages of current digital innovations to enhance the traditional design process.

Using the example of a small-sized yet technically complex project with many mutually interactive elements of design needing to be coordinated, the design team made a conscious decision at the start of the design process to utilise various industry leading 3-dimensional (3D) modelling software packages. However, this decision was taken much further than just undertaking 3D design modelling – the design team purposefully integrated the results from each modelling package into a cohesive, interactive modelling ‘space’ for the project. This paper provides details on this data coordination and integration process, and how the integrated model was used to produce the detailed design faster and more accurately than using traditional methods by removing the need for manual design updates for each design iteration.

The project hydraulic functionality was particularly sensitive to the physical arrangement and levels of the final designed storage structure and associated structures such as the overflow weir. This project provides an example of how the customary gap between theoretical hydraulic modelling and detailed engineering design can be effectively bridged by a design team who can use the hydraulic model to successfully support the design optimisation process. In particular the design team was driven to find balance between reducing the construction complexity and reducing the cost.

This paper then describes how the project 3D model used was updated to incorporate other key design and construction constraints on the project such as the predicted future sea level rise, and local geotechnical conditions. Changes to the hydraulic design model, and to the baseline 3D geological and surface terrain model in turn informed the detailed structural and mechanical design. The ability to coordinate 3D information between each model was key to getting this optimisation completed quickly and without the risk of manual error. By using and integrating the various 3D models, the whole project design (structural, mechanical, hydraulic, geotechnical and civil) was produced as a coordinated package and completed in a shorter time period compared with a traditional design process and without the risk of mis-aligned design elements.

In summary, using the hydraulic model and coordinated 3D design models has meant that the project engineers were able to quickly and accurately develop a cost effective, constructible configuration for the storage structure, whilst also robustly demonstrating that the project would result in a more than 95% reduction in total annual wastewater flows to the foreshore. The client has also been delivered a design that will be faster, safer and easier to construct.