Developing a system dynamic plus framework for water-land-society nexus modeling within urban socio-hydrologic systems

Urban ecological security evaluation and spatial correlation research-----based on data analysis of 16 cities in Hubei Province of China

When water utilities establish water loss control programs, they traditionally focus on apparent loss rather than real loss when considering economic feasibility in the water sector. There is an urgent need for new management approaches that can address complex relationships and ensure the sustainability of natural resources among different sectors. This study suggests a novel approach for water utilities to manage water losses from the water-energy (WE) Nexus perspective. The Nexus model uses system dynamics to simulate twelve scenarios with the differing status of water loss and energy intensities. This analysis identifies real loss as one of the main causes of resource waste and an essential factor from the Nexus perspective. It also demonstrates that the energy intensity of each process in the urban water system has a significant impact on resource use and transfer. The consumption and movement of resources can be quantified in each process involved in the urban water system to distinguish central and vulnerable processes. This study suggests that the Nexus approach can strongly contribute to quantifying the use and movement of resources between water and energy sectors and the strategic formulation of sustainable and systematic water loss management strategies from the Nexus perspective.

Regional complex system simulation optimization through linking governance and environment performance: A case study of water environmental carrying capacity based on the SDES model

Focal Area: This white paper proposes advanced data-driven and computing techniques to improve the predictability of extreme climate events (precipitation) and focuses on comprehending their impact dynamics to enhance resilience of urban systems. Science Challenge: In urban systems, climate change has presented significant challenges related to accurate spatiotemporal prediction of extreme climate events (heavy precipitation) and their impacts, i.e. flooding. The occurrence of extreme climate events and their compounding repercussions on the built environment make urban systems increasingly more vulnerable. The interactions between extreme climate events, urban systems, and the corresponding impacts are irregular, non-linear, and dynamic, making it difficult to standardize resilience. As it stands, the management of complex urban systems is affected by uncertainties related to the nature of short- and long-term consequences caused by extreme events.

Non-technical summary: The world is facing multiple interconnected crises, from climate change and economic instability to social inequalities and geopolitical tensions. These crises do not occur in isolation; instead, they interact, reinforce each other, and create unexpected ripple effects – forming what is known as a polycrisis. Traditional ways of analysing problems often fail to grasp these interdependencies, making it difficult to find effective responses. We draw on system archetypes to describe and exemplify three polycrisis patterns. These provide a structured way to analyse how multiple crises unfold and interact, as well as insights into how to navigate such complexity. Technical summary: The concept of a polycrisis describes the complex interconnections between global issues, which can lead to unexpected emergent behaviours and the possible convergence of undesirable impacts. Understanding these dynamics is crucial for anticipating compounded effects and for identifying leverage points for effective intervention. We propose that system archetypes – generic structures in system dynamics that capture recurring patterns of behaviour – can serve as a useful analytical tool to study polycrises. Specifically, we reinterpret three key system archetypes in this context: Converging Constraints (based on the Limits to Growth system archetype), Deepening Divides (based on Success to the Successful system archetype), and Crisis Deferral (drawing from the Policy Resistance system archetype). These patterns illustrate how resource limitations, structural inequalities, and short-term solutions can sustain or worsen crisis dynamics. Using real-world examples, we show how polycrisis patterns can be employed to map feedback structures between interacting crises and to guide effective interventions. Our work contributes to a more structured and systemic understanding of polycrises, by providing a tool to help researchers and policymakers better anticipate, navigate, and mitigate their effects. Social media summary: ‘Polycrisis patterns reveal how crises like climate change, economic instability, and inequality interact, amplifying their impacts’.

In the body of systems thinking, system dynamics (SD) is considered to be a powerful tool. However, when dealing with a social entity such as a smallholder group, SD is considered to be a researcher-centrist methodology that may not accurately reflect perspectives and social power sensitivities of all stakeholders. This paper reports on research in which, in an effort to enhance SD, these deficiencies are addressed through complementary application of soft systems methodology, which has strength in acknowledging multiple perspectives, and critical systems heuristics, which can explicitly address power asymmetry. A series of interviews and workshops was undertaken to identify the problematic situation of smallholder beef farming in Java. To describe its linkages, this problematic situation was then translated into a causal loop diagram from which the systems archetypes were identified. The nature of each archetype is described, and the implications for identification of the possible system leverage points are discussed. Copyright © 2014 John Wiley & Sons, Ltd.

The share of renewable resources in electricity generation, e.g. in Germany, is increasing. The power sector is thus becoming more dependent on climate/weather parameters. During the summer months of the last decade, numerous thermal power plants in Europe had to be throttled due to water shortages and high water temperatures. At the same time, Europe was confronted with a reduction in hydropower production. One method of securing a future electricity supply is to increase the reliability of the water supply for power plants. In this paper, scenarios are presented for future electricity production by hydropower and thermal power plants in the Elbe river basin. Electricity production in hydropower plants will decline by approximately 13 % by 2050. This decline is due to climate change and it could be compensated for by optimizing and modernizing existing hydropower plants. Due to higher efficiencies and the conversion of plant cooling systems, no water shortages are expected in most thermal power plants. However, water shortages are expected to affect the plants in the city of Berlin. Inter- and intra-basin water transfers constitute a possible adaptation option. While the transfer of water from the river Oder would be the most cost-efficient solution from Berlin’s perspective, the transfer of water from the river Elbe would have additional positive effects in the upstream Spree river sub-basin.

A novel hybrid systemic modeling into sustainable dynamic urban water metabolism management: Case study

Urban systems are dynamic, complex, and often involve multiple stakeholders, resulting in responses with distinct time lags. A resilient urban mobility system should be able to neutralize the effects of disruptive events (threats) while maintaining its essential state of functionality. Given the lack of studies addressing threats to urban mobility and the concurrent impacts on the urban mobility system, a holistic analysis considering key elements of transport systems and their interactions is necessary. Thus, this study aims to describe and analyze the dynamics involved in a resilient urban mobility system using qualitative system dynamics modeling. We start by identifying the main system components, threats, interrelations, and interconnections. Then, we create causal loop diagrams (CLD) of the urban mobility system under different conditions: (i) in the essential state of functionality, (ii) affected by a disruptive event and (iii) still functioning due to its resilience. Analyzing the CLDs indicated that the dynamics involved in a resilient urban mobility system have a preventive nature as it reflects the importance of transport policies considering climate change and disaster prevention policies/measures. In addition, the results showed that public opinion and incentives to use sustainable transport play an important role in balancing the system. Therefore, the negative effects of threats on the system, such as deaths, damage to transport infrastructures, and collapse of mobility performance, can be prevented. The outcomes of this study may be used to support the process of planning and building resilient cities.

Prospective Health Technology Assessment allows early decision making for innovative health care technologies. The main idea is to combine available domain knowledge with advanced simulation techniques in order to predict the effects of medical products and to find bottlenecks and weaknesses within the health system. In our recent publications a hybrid simulation approach with System Dynamics and Agent-Based Modeling has been presented. Hospital workflows have been modeled by state charts within agent behavioral models and have to be instantiated each time an agent is entering a hospital. This paper presents a mechanism to generate agents dynamically from SD models and extends the previously presented hybrid approach by process-oriented Discrete Event Simulation for hospital modeling. It connects processes to health care institutions and not to persons traversing them. Two extended example case studies show potentials for medical decision making using the three simulation paradigms in a common environment.

Multi-objective cooperative optimization of reservoir scheduling and water resources allocation for inter-basin water transfer project based on multi-stage coupling model

<p>Cities face increasing droughts and water shortages as a result of extreme meteorological conditions and expanding human pressure. Future projections estimate that over one billion urban residents will experience severe droughts and water shortages in the near future. Most scientific and policy debates emphasize climate change, population growth and urbanization as the major forces at the genesis of this apocalyptic future. In this paper we argue instead that the root causes of urban water crises have to be retraced in the socioenvironmental injustices enmeshed with the development of a city. For it is not society as a whole that reshapes drought events or trigger water shortages. Usually, the most powerful groups with greater privileges and access to resources, are those who play a more prominent role in decisions on water resource use and allocation, thereby shaping the propagation of drought phenomena more significantly.  Accounting for the heterogeneity of human societies is thus key to understand the dynamics of human-water systems and, more specifically, the temporal and spatial propagation of drought phenomena. Sociohydrological models have not yet accounted for the manners in which heterogeneous social groups intersect with drought propagation. This work advances current analyses by modelling heterogenous interactions between human and water systems alongside their unequal influences on the transformation of drought into uneven water crises. The Day Zero crisis in Cape Town constitutes the empirical basis of this work. On the one hand Cape Town’s urban geography epitomizes an unequal landscape of water access and vulnerabilities. On the other hand, Day Zero exemplifies an extreme drought event that will most likely occur across many urban areas. Using a system-dynamic framework we retrace the uneven consumptions of water across Cape Town metropolitan area and estimate the drought resilience trajectories for different social groups. In turn, the socio-hydrological model explores the distinctive implication that each trajectory has for the sustainability of urban water systems. Ultimately, we argue that the unsustainable water uses of the elite can transform a meteorological drought into an urban water crisis.</p>

Evolution of urban land and population system coupling micro–dynamics and macro-stability: Trends and paths

Due to the great complexity and the nonlinear and dynamic characteristics of joint optimization operations in inter-basin water transfer-supply systems (IBWTS), rational operating rules (water-transfer rules and hedging rules) are essential in water resources management at the planning stage. Currently, the water-transfer rules in optimization operation model are not reasonable as there is only one water-transfer rule curves for each recipient reservoir, so that they cannot reflect the refined water transfer especially when there is a small water shortage. Therefore, the purpose of this study is mainly to develop new water-transfer rules to improve the effectiveness of water transfer. That is, upper-and-lower water-transfer rule curves for each recipient reservoir and one water-transfer rule curve for one donor reservoir are developed to make water-transfer decisions. In the proposed rule, water transfer involves a combined decision-making process in consideration of water storages of both the recipient and donor reservoirs. Most importantly, when there is less water shortage in recipient reservoirs, the actual transferred water is no more than the water flow interpolated within the designed delivery capacity instead of only the designed delivery capacity in other existing rules. Because it is an interactive process of water transfer and water supply in the IBWTS operations, operation models coupled with the improving water-transfer rules and hedging rules are established for solving the operation problems. Finally, a North-line IBWTS located in Liaoning Province in China is employed as a case study. And a coarse-grained parallel PSO algorithm with a simulation model is employed for effectively deriving the operating rule curves (water-transfer and hedging rule curves). The operation results show that the proposed rule-based operation model are reasonable and can significantly reduce water transfer with less influence on the water-supply capability than other existing operating rules.

The process that, the equipment regulates internal voltage's amplitude and frequency (A/F) to generate changes in the electric network terminal power, plays a critical role in determining a power system's dynamic behavior. Traditional system analysis relies on the “quasi-steady state” assumption of constant frequency to investigate the network, and the results are often reasonable due to the network's time constant being fast enough compared to the internal voltage dynamics. However, the increasing integration of converter-interfaced equipment with fast A/F dynamics raises concerns about the network's power variations concerning the A/F, including the characteristics of potentially impacting power system dynamics. To address these concerns, this paper emphasizes the demands for analyzing the network's stimulation-response relationships under the dynamic practice of time-varying A/F. It provides a generalized method to establish explicit expressions for the original stimulation-response relationship of the network. On this basis, the dynamic characteristics potentially impacting the system dynamic processes are analyzed and elaborated. In addition, this paper identifies differences in the system's dynamic behaviors that may arise from commonly used static network relationships, even for system electromechanical dynamics. This work aims to lay the foundation for further understanding of the physics and analytics of the network under the equipment-regulated time-varying A/F.