Over five years we helped Watercare establish a comprehensive carbon baseline based on business-as-usual construction practices in New Zealand. Many of the projects – ranging from treatment works to pipelines – were in early planning stages with minimal information, requiring close collaboration with Watercare project managers to fully understand and accurately scope each project.

“You have to make a lot of big assumptions and make allowances for future, unplanned items,” says Jonny Breen, principal carbon consultant at Mott MacDonald. However, Jonny and colleagues were able to build on carbon models already created in the UK for utility company Anglian Water. These were adapted, taking account of different carbon emissions factors for New Zealand, to provide an advanced starting point for Watercare projects.

Moata Carbon Portal is linked with building information modelling (BIM). Over the last decade we have built a huge library of BIM assets – a virtual warehouse of components and assemblages – all of which are tagged with carbon data. Every Watercare project was first broken down into assets that could be matched with those in our BIM library. Updated with New Zealand carbon data, the BIM models gave instant figures for total carbon.

Our Watercare team set up workshops with the team responsible for Anglian Water’s carbon models. “One of the key pieces of this work was knowledge transfer,” Jonny explains.

The link between BIM design software and Moata Carbon Portal allowed Watercare and its designers and contractors to explore multiple construction and operational scenarios, and see the carbon implications as design changes were made. With a clear understanding of the programme’s carbon footprint, Watercare can use the information to start making reductions through project requirements, innovative design and efficient construction.