Wastewater Infrastructure Planning - Combining Renewals and Catchment Modelling Studies

Wastewater infrastructure expenditure is often planned through wastewater Catchment Modeling Studies and Renewals Programming. Catchment Modeling Studies are focused on meeting level of service criteria and providing for predicted growth, while renewals focus on maintaining reliability and operability of an ageing network.

Catchment Modeling Studies and renewals are often considered in relative isolation; however there is significant advantage to coupling the two processes and maintaining both programs as live documents. The results of continued investigations and condition assessments can have a major impact on the priority of planned projects along with directly impacting the preferred upgrade option and resulting cost. Running the two processes in parallel ensures that upgrade projects fully utilise the useful life of existing infrastructure while ensuring that upgrades to meet level of service requirements. This also resolves areas identified as being of high risk as much as possible. This can result in significantly different results from the Catchment Modeling Studies that if capacity and growth requirements are considered in isolation.

The following paper uses case studies to demonstrate the effect of this holistic approach.