200 University Avenue, Department of Civil and Environmental Engineering, University of Waterloo, ON, Canada N2L 3G1.
Water Res. 2011 Oct 15;45(16):4737-50. doi: 10.1016/j.watres.2011.06.001. Epub 2011 Jul 5.
Recently enacted regulations in Canada and elsewhere require water utilities to be financially self-sustaining over the long-term. This implies full cost recovery for providing water and wastewater services to users. This study proposes a new approach to help water utilities plan to meet the requirements of the new regulations. A causal loop diagram is developed for a financially self-sustaining water utility which frames water and wastewater network management as a complex system with multiple interconnections and feedback loops. The novel System Dynamics approach is used to develop a demonstration model for water and wastewater network management. This is the first known application of System Dynamics to water and wastewater network management. The network simulated is that of a typical Canadian water utility that has under invested in maintenance. Model results show that with no proactive rehabilitation strategy the utility will need to substantially increase its user fees to achieve financial sustainability. This increase is further exacerbated when price elasticity of water demand is considered. When the utility pursues proactive rehabilitation, financial sustainability is achieved with lower user fees. Having demonstrated the significance of feedback loops for financial management of water and wastewater networks, the paper makes the case for a more complete utility model that considers the complexity of the system by incorporating all feedback loops.
最近在加拿大和其他地方颁布的法规要求供水企业从长期来看实现财务自给自足。这意味着向用户提供供水和废水服务要全额收回成本。本研究提出了一种新方法，以帮助供水企业规划如何满足新法规的要求。为实现财务自给自足的供水企业制定了一个因果关系图，将水和废水管网管理框定为一个具有多重相互关联和反馈回路的复杂系统。采用新颖的系统动力学方法为水和废水管网管理开发了一个示范模型。这是系统动力学首次应用于水和废水管网管理。模拟的网络是一个典型的加拿大供水企业，该企业在维护方面投资不足。模型结果表明，如果没有主动的修复策略，该企业将需要大幅提高用户费用才能实现财务可持续性。当考虑到水需求价格弹性时，这种增加会进一步加剧。当企业采取主动修复策略时，通过较低的用户费用即可实现财务可持续性。本文通过展示反馈回路对水和废水管网财务管理的重要性，提出了更完整的公用事业模型，通过纳入所有反馈回路来考虑系统的复杂性。
