Preparing a consultant brief for a large wastewater infrastructure planning project - A case study of Project Storm 2

In 1996, Watercare Services commissioned its first dynamic computer model of its trunk wastewater collection network. Known as Project Storm, it was the largest water utility modelling project in New Zealand at the time. The construction of the model required interrogation, rationalisation and data cleansing of approximately 6,000 network components from both corporate asset management and GIS systems. The calibration of the model made use of 180 rain and flow gauges over its 400 square kilometre catchment area.

Project Storm was completed in 1999 and an international review panel concluded that the Project Storm model produced predictions that were as accurate as could realistically be achieved. Moreover, the panel noted that the project was well thought out and was delivered to a high standard of practice, and completed in accordance with recognised best practices. This fact was also recognised locally when Project Storm received an ACENZ Award.

Watercare has a programme in which its wastewater collection model is updated on a 10-yearly cycle, timed to coincide with the national census. The updates include the capture of latest rainfall and flow information to facilitate a full recalibration of the model and to reflect changes within sub-catchments. These changes include land development, population changes, and operational changes within the network itself. The update also provides an opportunity to utilise advances in modelling software technology and computer processing power. The 2006 update of the Watercare wastewater collection model was known as Project Storm 2.

In 2005, Watercare began work to prepare the project brief for Project Storm 2. A key focus in the development of the brief was an underlying objective that the Project Storm 2 model would be better than the original Project Storm model. Fundamental to this was to encourage the tendering consultants to bring innovation into the project and not to provide “regular old modelling”.

Project Storm 2 was completed in 2008 on budget. A peer review determined that the project was innovative, applied sound engineering judgement as well as an appropriate quality assurance procedure. The peer review also concluded that the Project Storm 2 model was a substantial improvement on the previous Project Storm model.

This paper comments on the challenges in preparing the Consultants’ Brief for Project Storm 2. It also provides discussion on the lessons learnt through the process, and ideas that may be useful for the planning and preparation of modelling briefs by client organisations in the future.