Water is an essential requirement for all, and is particularly critical in urban areas like Virar's Chikhaldongari, where the demand is significant. The water distribution network plays a crucial role in supplying water to all users amidst the city's growing population. To meet increasing demands, advanced computing systems, including modern hydraulic modeling and design software, are essential. In this study, WaterGEMS software was employed to evaluate and enhance the water distribution system's serviceability in Chikhaldongari. This includes steady-state analysis to determine hydraulic parameters such as pressure, velocity, head loss, and flow rate. Rapid urbanization exacerbates the pressure on existing networks, necessitating a forecast-based assessment of future water requirements. Therefore, to account for the growing population, this study also projects a population of approximately 28,783 by 2031 using arithmetic and geometric methods, growing to 39,773 and 40,189 by 2061, respectively. These data notify the need to design a new distribution system to meet future demand, assess current flaws, and optimize system efficiency. The WaterGEMS model incorporates 94 pipes covering 17.917 km and 94 demand nodes serving 17,792 end users. The simulation identifies critical areas with inadequate water supply pressure, guiding targeted infrastructure improvements. The main achievement of this research is that the new distribution system not only satisfied the anticipated water demand, but also made sure that the water delivery system would be durable and long-lasting. The research's novelty is characterized by its use of sophisticated modeling tools, dynamic simulation, comprehensive network analysis, future demand forecasting, focus on safety and sustainability, and targeted infrastructure improvements. In conclusion, the application of advanced modeling tools like WaterGEMS is pivotal in enhancing water distribution networks, ensuring they meet evolving demands sustainably. This proactive approach not only addresses current challenges but also prepares the infrastructure for future growth, thereby supporting the community's well-being and development.

This research aims to study the best technical-economic solution, for a hydropower plant located on Madeira Island. In this system exists three reservoirs. The first is in Covão, which supplies water for a small community and the others are located in Socorridos, where there is a turbine and a pump, and in Santa Quitéria, which contains another turbine. From Covão to Socorridos, there is only one pipe, which means the water is pumping and turbining along the operation day.

Simulations were developed in EPANET, to understand the pressure and velocity variations, along the entire system depending on the population needs. For these simulations, it was defined the pump and turbine characteristic curves.

This case study integrates solar and wind energy to compensate the pumping costs. Several scenarios were tested, to obtain the best solution.

In the optimization multipurpose project, it was used the Excel Solver to estimate the operation of the system and to increase the NPV. To solve this problem six different solutions were tested, varying the daily volume to turbine in Socorridos.

It was studied the integration with other energy renewable sources and selected a small land with approximately 5 ha near Covão, to install these energy sources. It was considered an average wind speed at 10 m height and the energy that is possible to produce by each solar panel with 787 Wp, along the day, for the selected location.

Based on this information, it was calculated the minimum number of wind turbines and solar panels, that is necessary to satisfy the energy consumption, for each scenario. The optimal solution was obtained based on the optimization function to maximize the NPV or the profit.

A treatment wetland (TW) is a nature-based solution for wastewater treatment that utilizes engineered systems to enhance processes that naturally occur in the environment. Computational Fluid Dynamics (CFD) is a consolidated technique used to design and perform the optimization of wastewater treatment systems. However, few CFD studies have addressed TW as this requires additional assumptions to properly include the porous flow modeling. This study aims to investigate the hydraulic patterns in horizontal subsurface flow treatment wetlands by using CFD coupled with the discrete element method (DEM), which provides a detailed representation of flow movement and porous media. The simulations were carried out in the software CFD-DEM. In terms of model settings, laminar flow and unsteady simulation were assumed. A case study using a 2 m long pilot-scale treatment wetland was used, as this model was previously validated for this setup. In order to support the design of a system with higher flow rates, three different flow rates were applied to check the differences in the system from the point of view of hydraulic behavior, in terms of flow direction, preferential flows, and hydraulic retention time. The results of the three scenarios were compared and a significant change was noted in the hydraulic behavior from the lower to the higher flow rate applied. The CFD-DEM simulations were effective to model the hydraulic patterns of the case under study and shown to be a good approach to accurately investigate hydraulics in TW, enabling operation optimization.

The macroturbulent dissipation in hydraulic jumps is accompanied by pressure fluctuations that act on the component structures of the stilling basin (slabs and anchors, walls) and on the forced dissipation elements (chute blocks, baffle piers and end steps) and may exposed them to fatigue, vibrations and cavitation due to pressure pulses. The National Water Institute (Argentina) has developed extensive research on pressure fluctuations in macroturbulent flows, contributing to define the influence of fluctuating pressures on the design of hydraulic jump stilling basins.

Macroturbulent energy dissipation generates dynamic actions on the component slabs, which are exposed to small relative displacements and the kinetic energy can be partially transformed into additional sub-pressure. Dimensionless coefficients related to fluctuating forces and moments were obtained by means of instantaneous measurements on piezometric taps distributed on an area that represents different rectangular slabs. Free hydraulic jumps on horizontal stilling basins downstream of a vertical sluice gate were considered, with Froude numbers between 3 and 6.

The characteristics of the coherent structures of the hydraulic jump downstream of a bottom gate were contemplated, considering the longitudinal position along the stilling basin. The autocorrelation coefficients of fluctuating forces were analyzed for different sizes of slabs, determining the magnitude of the time scale of the turbulence and the peak frequency of main vortices at different positions along the bottom.

A first conclusion is that Strouhal numbers coincide with those determined through energy density spectra obtained from records of fluctuating pressures. In addition, the slabs are subjected to stresses whose frequency is approximately constant for values of dimensionless size of slabs less than a critical value, and invariant with a distance up to 70% of the length of the hydraulic jump, adopting a monotonically decreasing trend towards downstream. Finally, pressure wave celerities are somewhat higher than those determined for jumps formed downstream of spillways.

Remote communities face challenges related to traditional power grids and distribution systems. Centralized generation and long-distance transmission cause energy losses and higher tariffs, and they affect the lifestyle in these villages. Local energy generation based on hybrid renewable sources and storage systems offers a solution. This approach not only reduces losses but is also a solution to the recent wave of negative or no electricity prices on the spot electricity market, as it adds flexibility and reliability to the system. By generating their electricity, communities can reduce their reliance on a centralized grid, mitigating the impact of price volatility. Microgrids that combine renewable energy with storage methods give communities further options. This study is divided into two main parts. The first part is a theoretical study on the integration of energy storage systems, particularly pumped storage power plants and hydrogen storage, in decentralized systems with more than one renewable generation source (hydropower and/or wind power and/or solar energy), detailing the main requirements and the technologies involved. The second part focuses on the application of these systems to an existing energy development plan for Marruge, a small municipality in northern Portugal threatened by desertification. Based on the generation and surplus forecast, two storage systems were dimensioned and optimized through simulations with the WaterGems/Hammer software. The main storage system is a pumped storage system supplemented by a hydrogen storage system. Improvements to the storage system were achieved by integrating a ram pump to increase the pressure in the hydrogen system using a hydropneumatic tank. Compared to a scenario without storage, better adjustment of the demand and supply curves was demonstrated. In the context of a local hydrogen economy, additional benefits for the community could be achieved by extending the payback period and shortening the payback period.

As the demand for water and energy increases, the interdependency between these two resources, known as the water-energy nexus, becomes a pressing concern. Energy is required for water treatment and distribution, while virtually all energy production processes require significant amounts of water. Renewable energy sources now make up nearly 38% of the world's total energy consumption, indicating a sharp increase in recent years driven by the growing awareness of the depletion of non-renewable energy and the destructive impact of fossil fuels. However, these energy plants require substantial amount of water, primarily for cooling, stressing the already limited water resources. Conversely, the emergence of new persistent contaminants has necessitated the use of advanced, energy-intensive water treatment methods. Coupled with the energy demands of water distribution, this has significantly strained the already limited energy resources. Therefore, it is important to understand both the water footprint of renewable energy technologies as well as the energy consumption associated with water treatment and distribution. Regrettably, no straightforward, universal model exists for estimating water usage and energy consumption in power and water treatment plants respectively. Current approaches rely on data from direct surveys of plant operators, which is often unreliable and incomplete. This study evaluates the potential of mathematical modeling and simulation in the water-energy nexus. We formulate a mathematical framework and subsequent simulation in Java programming to estimate the water use in hydroelectric power and geothermal energy and the energy consumption of the advanced water treatment processes, particularly the advanced oxidation processes (AOPs) and membrane separation processes and water distribution considering the hydrodynamics and hydraulic transients. The paper also addresses the challenges and prospects of actualizing mathematical modeling and simulation to the water-energy nexus. The findings of this study demonstrate mathematical modeling and simulation as reliable approach in navigating the complexities of the water-energy nexus.

The Dinaric karst, a globally recognized geological phenomenon, is prominent in the Republic of Croatia; it is characterized by numerous karst fields known for their exceptional water quality and quantity. This region hosts the highest concentration of hydroelectric power plants in Croatia, reflecting its significance in electricity production. With increasingly extreme precipitation events and surface runoff patterns, there is a growing interest among energy institutions to optimize water utilization. Leveraging natural features like karst fields as managed retentions presents a viable solution.

A specific focus lies on the catchment area surrounding the Gojak hydroelectric power plant near Ogulin, Croatia, where several karst fields experience seasonal flooding. However, uncontrolled water runoff leads to Lake Sabljaci overflowing. To address this issue, a proposal involves controlled water release from the Drežnica field to minimize losses and enhance water management efficiency. The initial step includes sealing the abyssal zone of the field and constructing a hydrotechnical facility for regulated water release.

By integrating the Drežnica field as a retention area alongside the existing infrastructure at the Gojak hydroelectric power plant, a more efficient water management system can be established. This coordinated approach aims to maximize the utilization of water resources for electricity generation, while reducing wastage through uncontrolled overflow. Ultimately, this strategy underscores the sustainable utilization of natural resources to enhance energy production in the region.

This paper investigates the integration of hydropower within Poland's waterenergy nexus, emphasizing its contribution to the country's renewable energy mix and sustainability goals. Introduction: Amidst Poland's energy transition, hydropower presents an opportunity to balance renewable energy production with water management practices. Methods: Utilizing a mixed-methods approach, we analyze data from Poland's energy sector, policy documents, and case studies of hydropower projects. Results: The analysis underscores hydropower's potential to enhance Poland's energy stability, reduce carbon emissions, and support sustainable water management. However, it also identifies barriers such as environmental concerns and regulatory challenges. Conclusions: Hydropower is pivotal in Poland's energy landscape, offering a renewable solution that aligns with both energy security and environmental sustainability objectives. For optimal integration into the national energy strategy, future efforts should focus on innovative technologies to minimize ecological impacts and enhance the efficiency of hydropower systems. This study highlights the necessity for policy frameworks that support the development of hydropower within the water–energy nexus, ensuring Poland's successful transition towards a more sustainable and resilient energy future. For optimal integration into the national energy strategy, future efforts should focus on innovative technologies to minimize ecological impacts and enhance the efficiency of hydropower systems. This requires a collaborative approach involving stakeholders across sectors to address regulatory, environmental, and technological challenges. Additionally, the adoption of advanced hydropower technologies and practices can serve as a model for other countries looking to harness the water–energy nexus for sustainable development.

Water and energy are each recognized as indispensable inputs for the sustainable development and economic growth of any country. Efficient water management and renewable energy can improve sustainable development and energy efficiency by advocating for the multifaceted integration of systems to optimize the utilization of water and energy resources.

The proposed integrated systems include smart water management for the real-time monitoring of water flow and quality, coupled with a leak detection mechanism to reduce wastage and associated energy costs. The incorporation of on-site renewable energy sources, such as solar or wind, is used to power the water treatment plants, thereby reducing reliance on convenient energy, as is the implementation of the pumps-As-turbine (PAT) system for energy recovery from the water networks. In a real case study in Africa, the Nampula water supply system, located in Mozambique, was selected as having promising potential for energy recovery. The application of a pumps-as-turbine (PAT) systems allows for a reduction in the initial system costs and its environmental impacts,. The micro-hydropower (MHP) project, with a capacity of ~23MWh/year, indicates significant efficiency gains. The economic analysis reveals an impressive internal Rate of Return (IRR) of ~40%, dependent on the energy selling price. The environmental benefits are also significant, with the potential avoidance of over 12 tons of CO2 emissions and a reduction in real losses by more than 10,000 m3/year, contributing to a total economic benefit of 7604 EUR/year, particularly in the African context.

This study emphasizes the need for proactive policy and regulatory frameworks that incentivize the adoption of water and energy-efficiency technologies. Public awareness and education campaigns play a crucial role in promoting responsible consumption practices and reducing overall resource demand. By integrating these technologies into a cohesive strategy, not only Pakistan, but also similar developing countries, can optimize water and energy use, promoting sustainability and environmental stewardship.

Water scarcity is a significant global challenge, particularly in agrarian countries like Pakistan, where 80% of freshwater resources are dedicated to agriculture. As an arid and semi-arid region, Pakistan needs to adopt efficient irrigation practices to ensure sustainable water use. This study calculates Crop Water Productivity (CWP) to identify the most feasible irrigation methods, using the Mirpur Khas (MPK) District in Sindh, Pakistan, as the study area. Wheat, a crucial crop in Pakistan, was selected for analysis during the Rabi season (November to April), which spans 160 days. By employing processed Landsat 8 imagery and the EEFlux model, based on the METRIC (Mapping ET at high Resolution with Internalized Calibration) approach, this study estimated the actual evapotranspiration (ETa) and CWP for the wheat crop. The results revealed that the ETa averaged 296.26 mm throughout the growing season, with the highest ETa values observed during the crop development stage (approximately 152 mm), indicating increased water requirements during midseason. The calculated CWP was 1.17 kg/m³, significantly higher than Pakistan's national average of 0.80 kg/m³, suggesting that the wheat crop in MPK is utilizing water more efficiently. These findings emphasize the potential of advanced remote sensing techniques and models like EEFlux to enhance water use assessments in agriculture, enabling more sustainable management of water resources. The method used in this study is both time-efficient and resource-efficient, offering a viable alternative to traditional methods that require extensive human resources. The method is quite feasible and can be applied to different areas with various crops. This study demonstrates that adopting technological advancements in water resource management can significantly improve irrigation practices, making it a crucial step toward sustainable agriculture in water-scarce regions like Pakistan.