Katalin Bene

Solar photovoltaic systems are the most dynamically expanding renewable energy technology, their capacities have doubled globally over the last two years. The transition to solar energy offers numerous advantages, it poses significant challenges for the electricity grid stability. These systems have high production fluctuation within the day and vast overproduction in peak hours. To improve stability, economic operation and efficiency of electricity network, both fluctuation balancing and excess energy storage are essential. Presently two technologies are mostly used: battery-based and pumped hydropower energy storage systems. This study focuses on evaluating the operating efficiency of solar-driven pumped hydropower energy storage system in the catchment of Lake Velence under changing weather conditions. Lake Velence has been struggling with severe drought problems for years, posing challenges to water experts, and making fair water distribution difficult for water users. The nearby northern hilly region of the lake provides suitable location for municipal-scale pumped hydropower developments in terms of social, techno-economic and topographical conditions. Furthermore, due to scarce water resources, inefficient operation could cause additional tension among water users, therefore, detailed evaluation of system efficiency is required, along with life-cycle economic analysis and hydrodynamic optimization of reservoirs and pipelines. Using potential reservoir locations identified in a case study from 2025 for pumped hydropower energy storage, together with meteorological data, we analyze and optimize in a self-developed Matlab model 1) the hydrodynamics of the system and 2) evaporation losses of reservoirs, on a daily basis over years, under changing weather conditions. Hydrological evaporation and hydrodynamic friction losses, together with possible interventions to reduce their negative effects, were assessed with life-cycle cost analysis to present environmental-social and economic benefits. Changing weather conditions have significant impact on operational efficiency and can negatively affect water requirements that raise conflicts among water users. The solely solar-driven pumped hydropower systems are spreading but still in their early stages of development. Long-term and extended data on their operation is still limited and their performance under changing weather conditions requires further research. This research investigates hydrodynamic and hydraulic operation efficiency and couples with economic life-cycle cost analysis, supporting guidance for optimization and evaluation of future developments.

This study presents a data-driven methodology to develop and close the continuous water balance of a cascaded hydrological system consisting of two upstream regulating reservoirs and a downstream lake. The analysis is based on monthly hydrometeorological and hydrographic data for the period 1998–2024. A baseline water balance model using raw measured data was first implemented, followed by two bias correction approaches based on multiple linear regression coefficient estimation. The first approach applies uniform coefficients across all months, while the second accounts for seasonal variability by estimating coefficients only for the December–May period, when systematic errors are most pronounced. Model performance was evaluated using calibration (1998–2017) and validation (2018–2024) periods, with Nash–Sutcliffe efficiency (NSE) and residual diagnostics used as evaluation metrics. The baseline model showed substantial cumulative deviations due to systematic errors (NSE: −0.28 and −5.13 for the two reservoirs and −18.70 for the lake), confirming the need for bias correction. Both correction approaches significantly improved model performance, with NSE values up to 0.89 for reservoirs and 0.83–0.86 for the lake during calibration. In validation, the seasonally adjusted model performed more stably in simulating water levels for Lake Velence (NSE = 0.72) than the uniform coefficient model (NSE = 0.60), particularly under extreme hydrological conditions. Residual analysis further indicated improved independence and homoscedasticity when seasonal structure was considered. The results demonstrate that water balance closure in the system is affected by distributed errors across multiple components rather than a single dominant source. The proposed methodology provides a practical, scalable framework for reconstructing consistent water balance time series in data-limited, regulated systems and supports the development of water management scenarios.

A Magyarország szomszédjában zajló háború következtében emelkedtek az energiaárak és az ellátási kockázatok, miközben az éghajlatváltozás hatására az extrém aszályos, vízhiányos nyarak konfliktusokat és gazdasági károkat eredményeznek. A hagyományos, fosszilis villamosenergia termelés hozzájárul az üvegházhatású gázok légköri kibocsátásához, amely tovább súlyosbítja az aszályos időszakokat. A Velencei-tó környéki népesség évtizedek óta dinamikusan növekszik, amely változó területhasználatot eredményez. A vízgazdálkodási problémák megoldása akuttá vált, a vízgyűjtő szűkös vízkészlete negatívan hat az ökoszisztémákra, a turizmusra, a mezőgazdaságra és a gazdasági kilátásokra. A dombvidéki településeken növekszik a villámárvizek kockázata, miközben alacsony a vízvisszatartás mértéke, de a telepített napelemes rendszerek aránya jelentősen meghaladja az országos átlagot. A kutatás a megújuló napenergia termelő kapacitások és a villámárvizek visszatartásának komplex vizsgálatát és integrált hasznosítási lehetőségét mutatja be egy dombvidéki település példáján keresztül. Megvizsgáltuk a napelemes kapacitások és a földrajzi adottságokat kiaknázó multifunkciós záportározók közös, többcélú hasznosítási lehetőségeit. Hidrodinamikai modellel vizsgáltuk a szivattyús energiatározó rendszer áramlási viszonyait, valamint azok multifunkciós használatát: csapadékvíz-gazdálkodás villámárvíz-mérsékléssel, évszakon átívelő zöldenergia tározás, mezőgazdasági, vadgazdálkodási, rekreációs és kék-zöld infrastruktúrák integrálása. A tározók tervezése figyelembe vette a földrajzi jellemzőket, a csapadék adatokat és lefolyást, az energiaigényeket, a napelemek teljesítményét. Az integrált rendszer optimalizálása többcélú, fenntartható vízhasználatra és alacsony karbon-lábnyomra történt. Egy dombvidéki település példáján bemutattuk az alacsony szén-dioxid-kibocsátású, költséghatékony, fenntartható vízgazdálkodás és energiatárolás kombinálási lehetőségével elérhető hasznokat. A módszertan elősegíti a fenntarthatósági célok - környezeti, társadalmi, gazdasági – térnyerését, továbbá a csapadékvíz visszatartással és többcélú felhasználásával csökkenti az éghajlatváltozás okozta negatív hatásokat, valamint elősegíti a helyi és regionális fejlődést. Ez az integrált megközelítés és módszertan mintaként szolgálhat más dombvidéki települések számára, valamint szomszédos önkormányzatok együttműködéséhez is.

Groundwater modeling in semi-arid regions presents significant challenges due to complex aquifer dynamics, limited data availability, and heterogeneous hydrogeological conditions. This study presents a comprehensive comparative analysis of three fuzzy expert system strategies for monthly groundwater level forecasting in the Al-Hsain Basin, Syria: localized models based on hydrogeographical grouping, a unified basin-wide approach, and an innovative behavioral clustering methodology. Using synchronized rainfall and temperature data from 35 monitoring wells over four years (2020–2024), we developed and evaluated fuzzy inference systems’ directional classification accuracy as the primary performance metric, categorizing groundwater level changes into rise, stable, and decline states rather than predicting continuous values. This choice reflects the qualitative nature of fuzzy expert systems and their suitability for groundwater management under data-limited conditions. The behavioral clustering approach achieved excellent overall performance with a mean accuracy of 0.74, outperforming localized models (0.71) and unified models (0.67). Behavioral clustering demonstrated effectiveness in 66% of wells, with individual accuracy improvements reaching up to 0.23, while reducing model complexity from five group-specific systems to three behaviorally coherent clusters. Localized models achieved optimal performance in 29% of wells where hydrogeological conditions aligned with spatial assumptions, whereas unified models provided consistent moderate performance across 89% of locations. The incorporation of lagged variables and seasonal indices in behavioral clustering models proved essential for capturing temporal complexity in semi-arid groundwater responses. Statistical analysis revealed lower intra-group variability in behavioral clusters (standard deviation 0.06–0.09) than in geographical groupings (0.08–0.14), confirming improved functional homogeneity through response-based organization. These findings indicate that fuzzy modeling strategy selection should be context-dependent, with behavioral clustering offering an effective balance between accuracy, interpretability, and generalization for regional groundwater management applications. The novelty of this work lies in isolating the effect of fuzzy system organization logic (localized, unified, and behavioral) on forecasting performance, robustness, and transferability, evaluated under an identical inference and time-series validation framework.

Climate change and irregular precipitation patterns have increasingly threatened groundwater sustainability in semi-arid regions like the Eastern Mediterranean. Specifically, in coastal Syria, the lack of quantitative understanding regarding aquifer recharge mechanisms hinders effective water resource management. To address this, this study investigates the dynamic relationship between rainfall and groundwater levels in the Al-Hsain Basin coastal plain using 48 months of monitoring data (2020–2024) from 35 wells. We employed a unified analytical framework combining statistical methods (correlation, regression) with advanced time–frequency techniques (Wavelet Coherence) to capture recharge behavior across diverse Quaternary, Neogene, and Cretaceous strata. The results indicate strong climatic control on groundwater dynamics, particularly in shallow Quaternary wells, which exhibit rapid recharge responses (lag < 1 month). In contrast, deeper aquifers showed delayed and buffered responses. A dual-variable model incorporating temperature significantly improved prediction accuracy (R² = 0.97), highlighting the role of evapotranspiration. These findings provide a transferable diagnostic framework for identifying recharge zones and supporting adaptive groundwater governance in data-scarce semi-arid environments.

The Lake Velence watershed faces increasing challenges driven by local and global factors, including the impacts of climate change, energy resource limitations, and greenhouse gas emissions. These issues, particularly acute in water management, are exacerbated by prolonged droughts, growing population pressures, and shifting land use patterns. Such dynamics strain the region’s scarce water resources, negatively affecting the environment, tourism, recreation, agriculture, and economic prospects. Nadap, a hilly settlement within the watershed, experiences frequent flooding and poor water retention, yet it also boasts the highest solar panel capacity per property in Hungary. This research addresses these interconnected challenges by designing a solar-hydrodynamic network comprising four multi-purpose water reservoirs. By leveraging the settlement’s solar capacity and geographical features, the reservoirs provide numerous benefits to local stakeholders and extend their impact far beyond their borders. These include stormwater management with flash flood mitigation, seasonal green energy storage, water security for agriculture and irrigation, wildlife conservation, recreational opportunities, carbon-smart winery developments, and the creation of sustainable blue-green settlements. Reservoir locations and dimensions were determined by analyzing geographical characteristics, stormwater volume, energy demand, solar panel performance, and rainfall data. The hydrodynamic system, modeled in Matlab, was optimized to ensure efficient water usage for irrigation, animal hydration, and other needs while minimizing evaporation losses and carbon emissions. This research presents a design framework for low-carbon and cost-effective solutions that address water management and energy storage, promoting environmental, social, and economic sustainability. The multi-purpose use of retained rainwater solves various existing problems/challenges, strengthens a community’s self-sustainability, and fosters regional growth. This integrated approach can serve as a model for other municipalities and for developing cost-effective inter-settlement and cross-catchment solutions, with a short payback period, facing similar challenges.

A Víztudományi és Vízbiztonsági Nemzeti Laboratórium Projekt (RRF-2.3.1-21-2022-00008) 6C alprojektje keretében jelenleg is folyamatban levő feladatunk a felszíni vizekre vonatkozó ökológiai vízigények meghatározási módszertanának felülvizsgálata. E tanulmányban az eddigi eredményeinket mutatjuk be. Az ökológiai vízigény jogszerű alkalmazása az operatív vízkészlet-gazdálkodás területén napjaink alapvető feladatává válik, ugyanakkor a klímaváltozás hatásainak csökkentése, és az azokhoz történő alkalmazkodás keretében egy folyamatosan felülvizsgálandó feladatot is jelent a vízkészlet-gazdálkodók számára. Fontos egy konszenzusos módszertan elfogadása, hogy az ökológiai vízigényre a vízkészlet-gazdálkodás keretében ne csak, mint korlátozó tényezőre tekintsünk, hanem úgy is, mint egy olyan fontos vízhasználatra, amely hozzájárul a vizeink jó állapotának eléréséhez, vagy megtartásához, a természetes élővilág fennmaradásához és ezen keresztül a fenntartható és méltányos vízhasználatokhoz is elegendő és jó minőségű vízkészletet biztosít. A fontosabb fogalmak használatára nemzetközi szakirodalmi áttekintést követően adunk javaslatot. Javasoljuk a környezeti vízigény (environmental flow) fogalmának a bevezetését, amely lehetővé teszi az integrált vízgazdálkodás keretében az élőlényegyüttesek szükségleteit leíró ökológiai vízigény és a társadalom vízigényének konszenzusos összehangolását. A környezeti vízigény meghatározására első lépésben egyszerű, standardizálható, hidrológiai módszertant javaslunk. A módszertan újdonságát adó lényegi eleme, hogy havi bontásban, a vízfolyás vízgyűjtőjének méretétől függően kerül meghatározásra a minimum ökológiai lefolyás értéke és szintén havi bontásban kell meghatározni a 80%-os tartósságú természetes vízkészlet értékét is. A kettő különbözeteként számítható hasznosítható vízkészlet pedig a társadalom számára maximálisan hasznosítható vízkészletet – azaz egyfajta felső korlátot – jelentene. Ez biztosítaná, hogy az így kialakuló – vízhasználatok által befolyásolt – tehát az ökoszisztéma számára ténylegesen rendelkezésre álló lefolyás követné az adott évben megjelenő természetes vízjárás dinamikáját, ugyanakkor lehetővé tenné a vízkészletek hatékonyabb hasznosítását is. A környezeti vízigény fogalmához igazodva a leírt hidrológiai módszerrel meghatározott ökológiai vízigények egy első közelítését adják a természetes ökoszisztéma fennmaradásához szükséges valós vízállapotoknak. A természet megőrzése érdekében az ökológiai vízigény így kiszámított konkrét értékei felülvizsgálhatók a vízfolyás hidromorfológiai paramétereinek és a biológiai elemek igényeinek figyelembevételével. Szükség esetén – például adathiányos vízgyűjtőkön, védett természeti értékek és/vagy fokozott társadalmi vízhasználati igények mellett – az ökológiai vízigény holisztikus meghatározási módszertan alapján, a társadalmi szereplők által kötött kompromisszum szerint módosítható.

Iraq has faced escalating water scarcity over the past two decades, driven by climate change, upstream water withdrawals, and prolonged economic instability. These factors have caused deterioration in irrigation systems, inefficient water distribution, and growing social unrest. As per capita water availability falls below critical levels, Iraq is entering a period of acute water stress. This escalating water scarcity directly impacts water and food security, public health, and economic stability. This study aims to develop a general framework combining decision support systems (DSSs) with Integrated Comprehensive Water Management Strategies (ICWMSs) to support water planning, allocation, and response to ongoing water scarcity and reductions in Iraq. Implementing such a system is essential for Iraq to alleviate its continuing severe situation and adequately tackle its worsening water scarcity that has intensified over the years. This integrated approach is fundamental for enhancing planning efficiency, improving operational performance and monitoring, optimizing water allocation, and guiding informed policy decisions under scarcity and uncertainty. The current study highlights various international case studies that show that DSSs integrate real-time data, artificial intelligence, and advanced modeling to provide actionable policies for water management. Implementing such a framework is crucial for Iraq to mitigate this critical situation and effectively address the escalating water scarcity. Furthermore, Iraq’s water management system requires modifications considering present and expected future challenges. This study analyzes the inflows of the Tigris and Euphrates rivers from 1933 to 2022, revealing significant reductions in water flow: a 31% decrease in the Tigris and a 49.5% decline in the Euphrates by 2021. This study highlights the future 7–20% water deficit between 2020 and 2035. Furthermore, this study introduces a flexible, tool-based framework supported by a DSS with the DPSIR model (Driving Forces, Pressures, State, Impacts, and Responses) designed to address and reduce the gap between water availability and increasing demand. This approach proposes a multi-hazard risk matrix to identify and prioritize strategic risks facing Iraq’s water sector. This matrix links each hazard with appropriate DSS-based response measures and supports scenario planning under the ICWMS framework. The proposed framework integrates hydro-meteorological data analysis with hydrological simulation models and long-term investment strategies. It also emphasizes the development of institutional frameworks, the promotion of water diplomacy, and the establishment of transboundary water allocation and operational policy agreements. Efforts to enhance national security and regional stability among riparian countries complement these actions to tackle water scarcity effectively. Simultaneously, this framework offers a practical guideline for water managers to adopt the best management policies without bias or discrimination between stakeholders. By addressing the combined impacts of anthropogenic and climate change, the proposed framework aims to ensure rational water allocation, enhance resilience, and secure Iraq’s water strategies, ensuring sustainability for future generations.

On steep-sloped watersheds, high-intensity, short-duration rainfall events are the leading causes of flash floods. Typical overland flow analysis assumes sheet-like flow with a shallow water depth. However, the natural creek beds in steep watersheds produce complex and intense flows with a shallow depth and high velocity. According to the hydrodynamical modeling processes for open channel turbulent flow, calculating rainfall-induced overland flow becomes a complex task. Steep topography requires a highly refined numerical mesh, which demands a more complex simulation process. Depth-integrated models with distributed parameters provide useful methods to capture the behavior of steep watersheds. This study investigates the watershed’s overland flow behavior by varying turbulent flow parameters and monitoring possible model errors. The refined modeling places a heavy demand on numerical solvers used for simulating the overland flow motion. This paper examines different depth-integrated model solvers applied to artificial watersheds and compares results produced by the different solver types. This study found that the Shallow Water Equation solutions produced the most consistent and stable results, with the Local Inertia Approximation solutions performing adequately. Adding Large Eddy Simulation to these solutions tended to overcomplicate Shallow Water solutions but generally improved Large Eddy solutions. The Diffuse Wave Equation solutions produced erratic results, losing stability and accuracy as watershed slopes steepened and flow paths became complex.