Capacity and Condition - The Critical Elements for Infrastructure Planning

Parliament is debating the Local Government Act 2002 Amendment Bill (No. 3), that includes a requirement for local authorities to prepare an infrastructure strategy for a 30 year period. Although this may seem onerous, infrastructure planning for water and wastewater utilities can be effectively streamlined by focusing on two main elements: capacity and condition. 

Cardno BTO carried out capacity and condition assessments for the Wanganui District Council’s Beach Road Pumping Station (that also contains wastewater pre-treatment), as a basis for preparing a 30 Year Infrastructure Plan. Two specific asset management tools were used in the assessments that were vital in streamlining the process: the visual assessment methodology (NZWWA, 2008), and pump performance testing. 

The visual assessment methodology ensures that the condition assessments of the civil, structural, mechanical, and electrical components were systematic and concise in identifying components of concern. 

Pump performance testing helps determine the deterioration in capacity as well as in efficiency (and therefore operational cost), by comparison to benchmark performance tests. The rate of deterioration compared with the expected gain from refurbishment identifies when a replacement or refurbishment should take place, which is a critical factor in infrastructure planning. 

The outcomes of the above assessments were used as the basis for scheduling improvements in the 30 Year Infrastructure Plan.