Prioritizing rehabilitation interventions of water supply infrastructures using infrastructure value index

Abstract

Water utilities face the problem of dealing with assets of very different nature, useful life, cost, age and condition. Asset valuation is important to establish rehabilitation priority of infrastructures in short-term and to analyse the different strategies of rehabilitation in order to maintain the service sustainable in the long-term. One of the most important steps of the asset valuation is the construction of cost functions. These cost functions are important for determining the fair value and the current replacement cost for water supply assets and for estimating the capital cost of future infrastructure. The current paper aims at the valuation of assets of water supply infrastructures in order to prioritizing rehabilitation interventions of water supply infrastructures using infrastructure value index. The methodology adopted was a three-step procedure: 1. Inspection and characterization of existing infrastructures; 2. Estimation of the replacement cost; and 3. Estimation and sensitivity analysis of the current value of existing infrastructures. This methodology was applied to a case-study in the south of Portugal. Results include the IVI calculation for different distribution pipe materials, ground storage and pumping stations, using the corrected useful life taking into consideration the conservation status of the respective assets. One of the most important factors in planning and managing water systems is to maintain the water service sustainable, which presupposes to prioritize the rehabilitation interventions in short and long-terms.