Using a Condition Model for Improved Renewals Forecasting of Stormwate Pipeline Assets

Managing limited fiscal resources to maintain service levels on ageing buried infrastructure requires a sound understanding of the condition of the assets, and how they deteriorate. The prohibitive cost of obtaining condition data and the need to improve renewals forecasting provided the impetus to develop a deterioration-based condition model for the Hutt City stormwater pipeline network.

This paper outlines the approach adopted and presents the fiscal and operational benefits of adopting a rigorous approach to renewals forecasting.

Deterministic analyses are used to define deterioration profiles that reflect the actual materials and operating conditions and require limited calibration. Modules developed within the InfoNet environment apply the deterioration profiles to the asset attribute and unit rates databases. The Infonet tools enable spatial representation of network condition profiles and provide broad reporting functionality. This provides the asset planning team with the ability to:

• Forecast asset renewal requirements based on physical deterioration
• Identify problem areas of the network in a spatial context
• Assess renewals requirements against criticality

Using a physical deterioration-based model demonstrated a significant adjustment of forecast renewals requirements, enabling the asset managers to defer renewals with added confidence that service levels will not be significantly affected.