Water4Cities: An ICT platform enabling Holistic Surface Water and Groundwater Management for Sustainable Cities

To enable effective decision-making at the entire city level, both surface water and groundwater should be viewed as part of the extended urban water ecosystem with its spatiotemporal availability, quantity, quality and competing uses being taken into account. The Water4Cities project aims to build an ICT solution for the monitoring, visualization and analysis of urban water at a holistic urban setting to provide added-value decision support services to multiple water stakeholders. This paper presents the main stakeholders identified, the overall approach and the target use cases, where Water4Cities platform will be tested and validated

A Resource Nexus Analysis Methodology for Quantifying Synergies and Trade-Offs in the Agricultural Sector and Revealing Implications of a Legume Production Paradigm Shift

Resource management in the sustainability context has increasingly been a key object that makes the application of holistic approaches an imperative need. The water–energy–food nexus concept offers tools for such system analysis in an integrated manner, through the identification and quantification of synergies and trade-offs. The agricultural sector often constitutes one of the main resource depletion hotspots. In this article, a nexus assessment methodological approach is developed for an agricultural context. Water, energy, food, land uses, and greenhouse gas emissions are perceived as nexus components. The methodology considers resource uses within and outside the biogeographical system boundaries, interpreting them as direct and indirect interlinkages. The methodology is validated on an actual case study, in Thessaly, Central Greece. Four nexus indicators are introduced to assess the impact of different land use planning scenarios. Legume production, which has been considered as a relatively beneficial land use among other crop choices, is tested against the four nexus indicators. Multiple advantages of such a land use paradigm shift are revealed, specific to the directions of food security, energy security, and economic sustainability

Simulation of a Water Distribution Network with Key Performance Indicators for Spatio-Temporal Analysis and Operation of Highly Stressed Water Infrastructure

An annual and lumped water balance assessment of a water distribution network is recommended by the International Water Association as a first step and prerequisite for improving the performance of the network by minimizing real/physical water losses, burst incidents, water theft, nonrevenue water, and energy consumption, among others. The current work suggests a modeling approach for developing the water balance of a network spatio-temporarily, in hour time-scale and neighborhood granularity. It exploits already established key performance indicators and introduces some new ones to highlight the potential in improving the management of a water distribution network when having a detailed spatio-temporal supervision, especially when the spatial and temporal conditions are variable. The methodology is applied in a seasonally touristic and hilly case study. Additionally, a pressure management scheme is applied to further exploit the potential of such a toolkit. For the investigated case study, the town of Skiathos, the annual real losses are estimated equal to 50.9–52.2% of the system input volume, while apparent losses are estimated to be about 5.6–6.6%. Losses depict intense seasonal variability. Real losses range from 38.8–39.6% in summer months to 63.3–64.7% in winter months, while apparent losses range from 8.4–9.3% in summer to 1.3–2.5% in winter. Annual water theft is estimated to be at least 3.6% of system input volume. Spatial variability, which is linked to the elevation and the different urban land uses is proven to play a significant role in the neighborhoods’ water balances and various key performance indicators are suggested and applied for the pressure control scheme. The annual potential savings due to the applied scheme rise up to 51,300 m3 for leakage and 53,730 m3 for pressure-driven demand

Modelling the Water‐Energy‐Food‐Land Use‐Climate Nexus: The Nexus Tree Approach

The United Nations Food and Agriculture Organization (FAO) has established the Water-Energy-Food Nexus, implying that the three commodities are inextricably linked forming a complex system of interrelations. Perceiving water, energy and food as a system variable with dependencies rather than a singularity suggests an approach of a more holistic view that can offer a sustainable plan for managing resources. In this article, the already established three-way Nexus is expanded to include two more dimensions, namely land use and climate and a framework for modelling the interlinkages among these dimensions is presented

Towards Ranking the Water–Energy–Food–Land Use–Climate Nexus Interlinkages for Building a Nexus Conceptual Model with a Heuristic Algorithm

The concept of the Water⁻Energy⁻Food nexus (WEF), as documented by the United Nations Food and Agriculture Organization (FAO), suggests that the three resources are thoroughly interrelated, shaping a complicated web of interlinkages. Perceiving the three commodities as an interdependent variable system, rather than isolated subsystems is a step towards a more holistic approach, and thus a prerequisite to introducing a sustainable scheme for better managing resources. In this work, the well-documented WEF nexus is broadened to a five-dimensional nexus, also involving land use and climate. A methodology for drawing the interrelations among the five dimensions and unreeling the complicated system of direct and indirect interlinkages is given. The intensity of interlinkages among nexus components is initially assessed through a three-point typology with interlinkage scoring corresponding to resource use in Greece. The typology is used and is further expanded to quantify successfully all interlinkages among nexus components with a proposed heuristic algorithm. Results are used to create the cross-interlinkage matrix that identifies food as the most influencing resource and water as the resource mostly influenced by other nexus elements. Results show that indirect interlinkages of multiple resources can be very significant and should not be ignored when planning nexus-coherent policy initiatives and investments in different sectors, in order to promote resource efficiency

Operationalizing the Nexus Approach: Insights From the SIM4NEXUS Project

Over the past decades, the understanding and assessment of cross-systems interactions have gained momentum in research and policy-support. As such, scientific literature on Nexus assessment methods and applications continues to grow, followed by numerous state-of-the-art reviews. Among the flexibility and variety of Nexus approaches, comprehensive, transferable and accessible methodologies with operational potential are missing. To address this gap, we introduce the SIM4NEXUS approach, which emerged from twelve test cases. Fledged from practice, the approach is a unique output in the Nexus research field. It is informed by the development of twelve case studies, which differ in spatial scope, socioeconomic and biophysical contexts, and Nexus challenges. The studies were conducted under similar conditions (e.g., timeframe and multidisciplinary teams of experts and dialogues with practitioners from policy and business). We find that transdisciplinarity and the integration of qualitative and quantitative methods are vital elements in Nexus assessments for policy support. Additionally, we also propose steps to advance Nexus assessments: 1) integration of the policy cycle in research (including monitoring and evaluation, and offer support during the implementation process), 2) multidisciplinary collaboration with different levels of engagement and financial support, 3) inclusion of ecosystems and other relevant dimensions (e.g., health) in the Nexus. Ultimately, the SIM4NEXUS approach provides practice-based guidance on conducting a Nexus assessment, and we recommend it for future Nexus assessments by the research community, institutions, and private actors

Smart Water Management for Cities

The deployment of real-world water monitoring and analytics tools is still far behind the growing needs of cities, which are facing constant urbanisation and overgrowth of the population. This paper presents a full-stack data-mining infrastructure for smart water management for cities being developed withinWater4Cities project. The stack is tested in two use cases - Greek island of Skiathos and Slovenian capital Ljubljana, each facing its own challenges related to groundwater. Bottom layer of the platform provides data gathering and provision infrastructure based on IoT standards. The layer is enriched with a dedicated missing data imputation infrastructure, which supports coherent analysis of long-term impacts of urbanisation and population growth on groundwater reserves. Data-driven approach to groundwater levels analysis, which is important for decision support in flood and groundwater management, has shown promising results and could replace or complement traditional process-driven models. Data visualization capabilities of the platform expose powerful synergies with data mining and contribute significantly to the design of future decision support systems in water management for cities