Assessment of lifecyle cost of urban water distribution infrastructures
Having good and working infrastructure is the dream of every urban resident. Having good and passable roads that make an area accessible and the presence of good drainage system makes life better and easier. However, the availability of water distribution is paramount to all urban lives. Having a proper and working water distribution network aids in improving the quality of life of the urban residents considering that it provides services to the high-density population in all urban centers. Slight or minimal disruptions in any of the urban center infrastructure especially water distribution can result in economic, social, political and environmental consequences (Marques 2014). To be in a position to maintain an ever working infrastructure network particularly the water distribution network, there is the need to develop a comprehensive infrastructure development and management needs lifecycle perspective. Designing the infrastructure for a particular useful lifetime and maintaining them in a good atmosphere and state in their entire life service, is the secret of having a well functioning infrastructure network. An integrated lifecycle assessment (LCA) lifecycle cost (LCC) simulations will aid any urban authority in enhancing the sustainability of any infrastructure network including the concrete bridge infrastructures.
Considering that all areas and regions are not equal, there is the need to independently examine each area before embarking on any water distribution plans. Moreover, the lifecycle of water distribution is varied which may result in physical flunks that prevents the plans or rather the infrastructure from meeting the initial expectations. Some of the reasons for the physical failure include: Variation in infrastructure’s physical condition and deterioration, variations in infrastructure operating conditions and inappropriate application of on-time maintenance and replacement activities. The author of this article has gone a step further in informing all the readers on the phases and the stages in each phase that are associated with the assessment of water distribution network (WDN)during its lifecycle. Moreover, these steps can be exploited to identify the optimal time of lifecycle extension activities application. Below are the proposed steps and phases:
Phase 1: Model development
Stage 1: data collection – at this stage the engineers and infrastructure planners collect data and information that is necessary to create and develop a water distribution network simulation and analysis (Higuchi 2008). Stage 2: Determining the network expected remaining life duration – at this stage there is the need to develop the network expected remaining life duration which is estimated regarding its design. Stage 3: developing the hydraulic simulation model of the network – hydraulic simulation model helps in determining the WDN performance under different failure scenarios
Phase 2: WDN evaluation
Stage 4: Generating failure scenarios – the generation of failure scenarios helps in evaluation of the WDN failure conditions in regard to the random nature of the pipe breaks. Stage 5: analysis of the network performance under generated failure scenarios – EPANET 2.012 software is utilized in this analysis to determine the performance of the network. Stage 6: Evaluation of total network reliability in each time stage – this stage deals with the calculation and development of WDN performance desirability which is quantified using the reliability-based indicators
Phase 3: LCC assessment
Stage 7: calculation of total lifecycle revenue – the sole revenue of the urban WDN is from subscribers’ payments which are divided into the cost of consumed water and the subscription cost for each demand node (Marques 2014). Stage 8: lifecycle cost calculation – it involves the calculation of water distribution network lifecycle from an economic perspective.
Phase 4: Setting strategies
Stage 9: Network cost-revenue analysis – the obtained network revenues and costs in stages seven and eight are put to use at this stage to develop the cost-revenue trade-off graph to show the reliability aspect of the network. Stage 10: Decision masking – infrastructure managers and engineers make their decisions based on the cost-revenue graph, funding constraints, and the network reconstruction costs.
However, not all data may be available when making all these decisions and at times, planners and engineers are forced to work with an assumption as in the case provided in the article of the Chahardange water distribution network in central part of Iran. The design life of this project is 25 years of which five years had already passed during the time of this study. Some of the important assumptions associated with water distribution network projects include: The rate of population growth rates in an area and the roughness coefficient of the pipes.
In conclusion, we can say the author succeeds in showing the importance of infrastructures to all urban residents especially water distribution network. With proper infrastructures an urban region stands a better chance of developing and witnessing an improvement in the living standards of the residents. Moreover, it is vital for planners and engineers to find a way to determine the optimal operation and maintenance periods of these networks in order to achieve highest efficiency and effectiveness.
Higuchi, S., and Macke, M. “”Cost-benefit analysis for the optimal rehabilitation of deteriorating structures.”.” 2008.
Marques, J., Cunha, M., and Savic, D. “”using real options in the optimal design of water distsribution networks.”.” J. Water Resour. Plann Manage.,, 2014.