Emerald Lifeline Implementation – Water Infrastructure Design Development through 3D Modelling

Abstract

The town of Emerald is supplied by two existing water treatment plants (WTP’s); the Opal Street WTP (installed in the early 1970’s) and the East Nogoa WTP (installed in 2015). The Opal Street WTP requires significant maintenance and upgrade works to ensure the ongoing reliability and compliance of the plant. Recent planning works completed by AECOM for Central Highlands Regional Council (CHRC), identified the need for augmentation of existing pipework at the Opal Street WTP to allow the plant to be taken offline to enable these much needed upgrade works. Further, the upgrade to the existing media filter outlet and chlorine dosing pipework was identified by CHRC as priority works for the site. AECOM utilised 3D digital survey and modelling technologies to undertake the detailed design for these works. There were several complexities involved in completing the design at the Opal Street site that prompted this approach, including: • Space constraints around existing buildings, filters, clarifiers and pipework; • The majority of connections into existing network were above ground and little to no flexibility due to flanged joints; and • Limited available shutdown times and operational flexibility within the plant due to water demand. Due to the nature of the brownfield site, AECOM and CHRC opted to use a combination of point cloud survey of the area around the existing filters and a topographical feature survey for the remaining site to complete the design works. Using the point cloud survey ensured maximum location accuracy of the existing filters, above ground network and most importantly the existing flanges for connections. This allowed for the creation of a 3D model to ensure conflicts with surrounding pipework and structures were avoided during the early design stages. The 3D point cloud survey was found to have the following benefits / challenges: • Theoretical accuracy of the scan was within +/- 1 mm even though accuracy of the scan was influenced by constraints at the site, or on where the point cloud stations could be set up. • The scan was completed with red-green-blue (RGB) colours to match the colours of existing infrastructure on site The computational power required to process the raw point cloud due to the extremely large data set. From the point cloud survey, a 3D model was created of the proposed network upgrades utilising AutoCAD Civil 3D. The model was created with pipes and fittings based on manufacturers dimensions and where possible, the manufacturer supplied individual 3D fitting models. This maximised the accuracy of the work by representing all pipework and fittings in the model as they would be constructed on site. Use of these tools provided the ability to visualise and detail complex fitting arrangements, avoid clashes, and optimise constructability. Due to the accuracy of the models, greater confidence was achieved. As a result, construction cost and program risks were reduced. As the water industry matures in its use of Building Information Modelling (BIM), this project represents a practical and scalable approach for water utilities that can be applied on a wide range of projects.