Water Asset Management International 4.1 (2008) 02-06

Whole life optimisation model for water distribution: using modelling optimisation techniques to explore cost effective mains rehabilitation in Kampala City, Uganda

H. Mutikanga

National Water and Sewerage Corporation, Kampala, Uganda

J. Sseguya and K. Vairavamoorthy

UNESCO-IHE, Delft, The Netherlands

As the assets in the ground continue to age, concern is growing about their continuing performance and the risks of future failure. Like most other utilities, water authorities must manage many aging capital assets that are in varying degrees of deterioration; some of which are nearing the end of their useful lives. Rehabilitation and or/ replacement of deteriorating pipe components demands huge sums of money from annual budgets of water utilities worldwide and yet the funds available for rehabilitation of these assets is limited. It is important, therefore that the available funds are used in the most effective manner. In order to ensure that the available funds are used in the most effective manner, it is important that their capital maintenance decisions not only reflect costs borne now but also the likely costs in the future, and how these can be optimised. This paper attempts to address the issue of optimal Whole Life Costing (WLC) rehabilitation and maintenance strategy of water distribution assets using genetic algorithm technique. The whole life cost approach for rehabilitation and maintenance of water distribution systems is aimed to optimise the present value of pipe replacement, repairs and cleaning costs over a defined analysis period while requirements for water standards are fulfilled. The WLC analysis depicts a rehabilitation strategy over a defined analysis period together with the corresponding cost profile. H. Mutikanga, J. Sseguya & K. Vairvamoorthy use a case study in Kampala City, Uganda to demonstrate that the genetic algorithm can assist in planning of rehabilitation of water distribution systems.

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