Watercare's central interceptor wastewater model - Improving accuracy by including seasonal variation
Annual Conference
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Watercare Services are in the process of developing a consent application and concept level design for the Central Interceptor – a proposed sewer tunnel that seeks to address the key business drivers of asset duplication, capacity for growth and mitigation of targeted combined sewer overflows. This new sewer tunnel will extend approximately 15 kilometres under the city, replacing the existing Western Interceptor, and connect to Watercare’s wastewater treatment plant at Mangere.
A crucial aspect of the Central Interceptor is optimising the wastewater system’s conveyance, storage, and treatment capacities to ensure the least whole of life cost. To achieve this, Watercare is working closely with AECOM to update and enhance their trunk sewer system model – known as the Project Storm 2 model.
A key aspect of enhancing the model’s accuracy is to upgrade it to better represent the significant effects of the seasonal variations in base flows.
This paper will present the methods and results of this model enhancement and improved correlation to long-term flow data records. This paper also discusses the importance of this work in ensuring an optimal configuration of the Central Interceptor and how it allows for a best-practice assessment of the upgrade requirements of the wastewater system - as an integrated unit.