Dynamics of Coupled Natural-Human-Engineered Systems: An Urban Water Perspective on the Sustainable Management of Security and Resilience

Elisabeth H Krueger, Purdue University

Abstract

The security, resilience and sustainability of water supply in urban areas are of major concern in cities around the world. Their dynamics and long-term trajectories result from external change processes, as well as adaptive and maladaptive management practices aiming to secure urban livelihoods. This dissertation examines the dynamics of urban water systems from a socialecological-technical systems perspective, in which infrastructure and institutions mediate the human-water-ecosystem relationship.The three concepts of security, resilience and sustainability are often used interchangeably, making the achievement of goals addressing such challenges somewhat elusive. This becomes evident in the international policy arena, with the UN Sustainable Development Goals being the most prominent example, in which aspirations for achieving the different goals for different sectors lead to conflicting objectives. Similarly, the scientific literature remains inconclusive on characterizations and quantifiable metrics. These and other urban water challenges facing the global urban community are discussed, and research questions and objectives are introduced in Section 1.In Section 2, I suggest distinct definitions of urban water security, resilience and sustainability: Security refers to the state of system functioning regarding water services; resilience refers to ability to absorb shocks, to adapt and transform, and therefore describes the dynamic, short- to medium-term system behavior in response to shocks and disturbances; sustainability aims to balance the needs in terms of ecology and society (humans and the economic systems they build) of today without compromising the ability to meet the needs of future generations. Therefore, sustainability refers to current and long-term impacts on nature and society of maintaining system functions, and therefore affects system trajectories. I suggest that sustainability should include not only local effects, but consider impacts across scales and sectors. I propose methods for the quantification of urban water security, resilience and sustainability, an approach for modeling dynamic water system behavior, as well as an integrated framework combining the three dimensions for a holistic assessment of urban water supply systems. The framework integrates natural, human and engineered system components (“Capital Portfolio Approach”) and is applied to a range of case study cities selected from a broad range of hydro-climatic and socio-economic regions on four continents. Data on urban water infrastructure and services were collected from utilities in two cities (Amman, Jordan; Ulaanbaatar, Mongolia), key stakeholder interviews and a household survey conducted in Amman. Publicly available, empirical utility data and globally accessible datasets were used to support these and additional case studies.The data show that community adaptation significantly contributes to urban water security and resilience, but the ability to adapt is highly heterogeneous across and within cities, leading to large inequality of water security. In cities with high levels of water security and resilience, adaptive capacity remains latent (inactive), while water-insecure cities rely on community adaptation for the self-provision of services. The framework is applied for assessing individual urban water systems, as well as for cross-city comparison for different types of cities. Results show that cities fall along a continuous gradient, ranging from water insecure and non-resilient cities with inadequate service provision prone to failure in response to extant shock regimes, to water secure and resilient systems with high levels of services and immediate recovery after shocks.

Degree

Ph.D.

Advisors

Borchardt, Purdue University.

Subject Area

Climate Change|Aquatic sciences|Ecology|Economics|Hydrologic sciences|Management|Sustainability|Urban planning|Water Resources Management

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