The global and local environments are experiencing profound transformations in the 21st century, primarily due to the adverse impacts of climate change. Increasing temperatures and shifts in precipitation patterns present challenges to the natural world and human-made structures. Countries and settlements strive to reduce carbon dioxide emissions through the broader use of renewable energy sources. Adaptation to changing conditions is highly emphasized. These circumstances can be improved by more efficient and multipurpose uses of existing infrastructures or with small-scale expansions and broader, more complex use of renewable resources. A small settlement at Lake Velence, Nadap, has the highest ratio of solar panels in Hungary. It can be achieved by combining this advantage with its hilly location, sustainable energy security, and economic benefits. This paper develops a theoretical methodology for how rainwater and gravity energy storage can be utilized using the geographical characteristics of the settlement and its existing solar panel capacities. The methodology uses rainwater budget modeling, local solar-cell capacity calculation, and the selection of state-of-the-art mechanical gravity energy storage systems based on a literature review. Additionally, this paper aims to develop a rainwater management system that optimizes crop irrigation and maximizes energy storage in hilly settlements, with the cooperation of stakeholders, in a multidisciplinary approach.

Climate change has further exacerbated long-standing water use conflicts in the Lake Velence catchment area in Hungary. The lake is the ecological, social and economic central element of the area, with water scarcity as water levels having fallen to record lows in recent years due to severe summer droughts. As a result of infrastructure developments in the 20th century and the significant waves of immigrants in recent decades, the lake and its surroundings have been heavily modified, transformed into an artificial waterbody, while land and water use has significantly altered. Besides these negative effects on water resources and the lake’s water level, settlements in the catchment area have become the top solar energy producers per housing in Hungary in recent years. The aim of this research is to identify and develop a possible inter-basin water recharge solution that meets societal needs based on the suggested development ideas formulated in questionnaire responses. A sustainable alternative of these solutions is pumping from a nearby catchment, that was evaluated in detail. Based on ecological considerations, a multi-criteria analysis summarizing nearly 100 water quality and quantity parameters was developed to ensure that water supply meets qualitative requirements. To ensure economically sustainable operating costs, the nearby solar capacities were used for pumps operation and energy storage. For energy demand and carbon emissions reduction, the uphill pumping was complemented with a downhill turbine hydropower recovery system. Several scenarios of the pumped water recharge system were considered and hydrodynamically optimized in Matlab. The return on investment of the inter-basin pumped water replenishment systems were evaluated as well as the carbon emissions to assure additional economic benefits and low carbon-footprint. A bottom-up methodology with large scale stakeholder involvement that assesses social needs and applies well-balanced the three pillars of sustainable development, can achieve a Pareto effective displacement even during the development of a water replacement system at the catchment level and beyond, on an inter-basin level. With a comprehensive methodology developed for pumped water recharge from an external catchment using existing renewable energy sources, the deteriorating social atmosphere and ecological conditions caused by climate and land use changes may be improved. In the meantime, even economic benefits can be increased, all with a low energy demand and carbon footprint, in a sustainable way.

Climate change manifested its adverse impacts last year, with an extreme drought leading to a drastically low water level in Lake Velence, Hungary. Nature-based solutions have the potential to alleviate these impacts locally. While a few initiatives have been implemented in Hungary, widespread adoption of these solutions is expected to be a goal for the more distant future. This research focuses on one catchment at Lake Velence to evaluate decision-maker's readiness and urban water management infrastructure for broadly implementing nature-based solutions. Methods include delineating the stormwater system and creating a numerical model to evaluate rainfall-runoff processes and the possible impacts of nature-based retentions. Surveys among local mayors were conducted to assess their perception of existing water infrastructures and implementations of nature-based solutions. Its widespread use may become significant, but its effect on the lake's water level remains negligible.

Szigetköz—a large island of the Danube in Hungary—is attracting a new wave of interest in water-related regional development projects from the public and private sectors alike. The revived interest in the Szigetköz floodplain area, which has historically endured the adverse effects of large-scale water management initiatives, draws attention to the necessity for careful consideration and the active involvement of local stakeholders in the decision-making process. In our research, we conducted various stakeholder engagement activities, including interviews, questionnaires, and workshops. These activities helped define the problems and objectives of each stakeholder group. Through collaborative consultations, we gathered over 100 proposed water related development project ideas. Additionally, to address key issues in project development and selection, we evaluated the integrative potential of each proposed project, considering the number of distinct water management issues it addressed. We also assigned an attitude score to each project, derived from the diverse objectives of various stakeholder groups, and analysed these quantities using a multiple-criteria analysis. This paper details a novel approach to assess and rank the proposed water-related regional development project ideas based on the calculated integrative potential and attitude scores. The goal was to prioritise and further develop these proposed projects to benefit Szigetköz and its surrounding areas. Main results of the study have shown the average project scored between 0.33–0.50 in integrative potential out of a maximum of 1.00 For positive attitude score the average was between 0.28–0.43, out of a maximum of 1.00 while for the negative attitude score the average project scored between -0.14–0.00 out of a minimum of -1.00. The ranking of projects that was based on these scores, highlighted three types of proposed projects that need to be further developed in different ways. The top-ranked positive attitude integrative projects need cost-benefit calculations involving all ecosystem services to justify their economic sustainability. Top-ranked opposing attitude integrative projects need conflict resolution to be socially sustainable. Finally, project ideas that scored low on integrative potential need to be developed to make use of blue-green infrastructure, and circular economical advancements to foster their environmental sustainability.

Traditionally, stormwater management strategies were designed to evacuate water swiftly and efficiently to mitigate flood risks. However, water conservation has become a crucial concern with growing environmental awareness, raising damage costs due to climate change and sustainability goals. Urban stormwater capture and utilization are essential for maintaining soil moisture levels, irrigating green spaces, reducing urban heat islands, supporting diverse wildlife, fostering ecological balance, and improving living conditions. This study focuses on a dynamically growing Hungarian city, Érd, with rapidly changing land use and utilizes the numerical Storm Water Management Model to simulate various water resources management scenarios. The simulations revealed multiple vulnerabilities in the channel network, leading to a comprehensive reevaluation and redesign. This redesign integrates nature-based solutions, enhancing the system's effectiveness and climate resilience with limited territorial possibilities. By comparing various design approaches, this research demonstrates that incorporating nature-based infrastructure at residential and subwatershed levels substantially improves flood mitigation and increases precipitation retention capabilities, making traditional infrastructure developments unnecessary. The findings underscore the need for innovative, adaptive infrastructure solutions. Implementing nature-based solutions mitigates flooding and contributes to resilient, sustainable urban water management systems that are better prepared to handle the challenges of a changing climate. This study underscores the critical importance of innovative infrastructure solutions and the positive benefits of nature-based solutions in fostering resilient and climate-adaptive urban water management systems in cities with small open spaces, rapid population growth, and scarce financial resources.

The adverse effects of climate change on water resources have been demonstrated recently. The shallow surface and groundwater levels throughout Europe in 2022 have not been restored, even during the winter-spring recharge period. Water scarcity causes economic damage and may lead to food supply shortages and social tension. For Lake Velence, extreme drought caused damage throughout the watershed. The record low water levels kept away tourists and reduced the revenues. Stakeholder cooperation on sustainable water-related developments is essential to overcome the water deficit in the area. Surveys among local mayors confirmed that there is an affinity and possibility to sustainably utilize rainwater with the application of nature-based solutions. These infrastructures have low impacts on the lake’s water level while noticeably improving plant and agricultural irrigation, though the benefits are mostly unknown among stakeholders. Consequently, profitability per area unit for agricultural and farming activities can be increased. The research quantifies the possible positive effects of economic incentives used to implement nature-based solutions in the hilly settlements of Lake Velence; they sustainably increase the yield of agricultural production and food security and economically beneficial tools for mayors to optimize placement of nature-based solutions within the catchment to achieve adequate soil quality and additional social benefits.