The water sector is, currently and for the foreseeable future, challenged by rising levels of uncertainty in demand and availability of water, in a context of aging infrastructure and limited investment. In order to support strategic planning, water companies need a way to assess how their system behaves when faced with a range of changing conditions (climatic trends, asset deterioration, behavioral patterns, etc.) as well as accidents/incidents and/or extreme events (wildcards). In this study, a resilience assessment methodology was demonstrated, with ‘stress tests’ alternative water system configurations (including systems designed with decentralized or distributed philosophies) under a range of scenarios and extreme events. A ‘resilience profile graph’ was developed to quantify the performance of each configuration. The methodology was applied to the real-world urban water system of Oasen, which supplies the eastern part of the Province of South Holland, where the current system configuration and two potential future configurations were tested (one decentralized and one distributed). We show how the concept of resilience, operationalized through this methodology, can assist long term decision making and support strategic infrastructure planning.

Centralized urban water management currently faces multiple challenges, both at the supply side and the demand side. These challenges underpin the need to progress to the decentralization of urban water, where multiple distributed technologies (water-aware appliances, rainwater harvesting, greywater recycling, sustainable urban drainage) are applied in an integrated fashion and as a supplement to centralized systems to design more resilient neighborhoods. However, the methods and tools to assess the performance of these distributed solutions and provide management support for integrated projects are still few and mostly untested in real, combined cases. This study presents a simulation-based framework for the quantitative performance assessment of decentralized systems at a neighborhood scale, where different technologies can be linked together to provide beneficial effects across multiple urban water cycle domains. This framework links an urban water cycle model, which provides a scenario-based simulation testbed for the response of the whole system, with key performance indicators that evaluate the performance of integrated decentralized solutions at a neighborhood scale. The demonstrated framework is applied to provide an ex ante evaluation of SUPERLOCAL, a newly developed area in Limburg, the Netherlands, designed as a circular, water-wise neighborhood where multiple decentralized technologies are combined.

Sustainable Urban Water Management (SUWM) is a paradigm in which decentralisation is key. There has been little work directed towards the large-scale possibilities of decentralised water systems and their implications on the functioning of the centralised (potable) water system. This study includes both a historical and future (scenario) analysis of decentralised developments. Integrated morphological socio-technical scenarios are combined with quantitative water flows for a case study (the Province of Limburg, the Netherlands) and examined by a transdisciplinary group of experts. The study shows how SUWM measures which focus on climate adaptation and circularity can have a significant impact on existing centralised potable water systems. In turn, influencing the total water and peak demands and thus resulting in different utilisation rates. This can result in more system failures (e.g., longer residence time, bacterial growth, reduced self-cleaning capacity), significant changes in the centralised infrastructure (e.g., more wells), increasing water bills (e.g., inequalities), and the preservation of aquifers for future generation. Different scenarios either have regime-reproducing or regime-diversifying impacts. SUWM measures are studied in isolation and thus externalities are not fully considered. Therefore, when planning for decentralised SUWM solutions, a systems thinking approach is recommended, which takes into account externalities.

As Europe is faced with increasing droughts and extreme precipitation, countries are taking measures to adapt to these changes. It is challenging, however, to navigate through the wide range of possible measures, taking into account the efficacy, economic impact and social justice aspects of these measures, as well as the governance requirements for implementing them. This article presents the approach of selecting and analysing adaptation measures to increasing extreme weather events caused by ongoing climate change that was developed and applied in the H2020 project BINGO (Bringing Innovation to Ongoing Water Management). The purpose of this project is (a) to develop an integrated participatory approach for selecting and evaluating adaptation measures, (b) to apply and evaluate the approach across six case-study river basins across Europe, and (c) to support decision-making towards adaptation capturing the diversity, the different circumstances and challenges river basins face across Europe. It combines three analyses: governance, socio-economic and social justice The governance analysis focuses on the requirements associated with the measures and the extent to which these requirements are met at the research sites. The socio-economic impact focuses on the efficacy of the measures in reducing the risks and the broad range of tools available to compare the measures on their societal impact. Finally, a tentative social justice analysis focuses on the distributive impacts of the adaptation measures. In the summary of results, we give an overview of the outcome of the different analyses. In the conclusion, we briefly assess the main pros and cons of the different analyses that were conducted. The main conclusion is that although the research sites were very different in both the challenges and the institutional context, the approach presented here yielded decision-relevant outcomes.

This chapter comparatively analyses the policy and governance contexts of six European regions that are affected by different hydrological impacts of climate change. The results demonstrate that a major governance strength across regions lies in the organization of management capacities to deal with existing water-related risks. For example, the Dutch context focuses on water safety, Cyprus has a clear policy framework to deal with water scarcity and in the Norwegian city of Bergen, wastewater is well managed. As a consequence of this focus on present-day risks, climate adaptation governance also focuses on historical risks. New or exacerbated risks posed by climate change remain largely untreated, and responsibilities for dealing with climate-related risks remain unspecified, as also becomes clear in the German and Spanish cases. A high degree of governmental fragmentation is identified as another point of weakness. Identified most clearly in the Portuguese case but recognizable in all regional contexts, different subdomains of water management are dealt with under separate policies and are governed by different responsible agencies. Consequently, information about current performance of the water system is scattered and coordinative efforts, which are key to developing adaptation strategies, are hampered.