As climate change and a growing global population are putting increased pressure on our already stressed water resources, improving the ways we assess and manage clean water supply has quickly become one of our generation’s most pressing issues. While the emergence of new water treatment- and extraction techniques has allowed previously unobtainable water resources to be made accessible, there are still large quantities of water, while available at first glance, are unavailable from an allocation perspective. This includes water needed for the continued maintenance and operation of vital ecosystems services, water under quality constraints, and water deemed to be technically unfeasible or economically too expensive to obtain.
In this study we introduce a new flexible framework for assessing the total clean water supply for a predefined area and time period. We first defined the stored volume of water within the area through the spatial delineation of relevant water bodies, for which the maximum capacity and current storage was calculated. Next, a water budget was constructed on the basis of the stored volume and involving the assessment of societal and environmental needs within the area, local priorities, and constraining factors, including water under quality constraints and technical constraints. We then assessed the difference between the total allocated volume of water and actually water usage to account for and to identify areas of potential reuse and/or targeted measures. Finally, the total reclaimed and reusable water supply at the end of the period was assessed accounting for any legal and regulatory constraints, as well as any potential additional losses due to evapotranspiration. This finally resulted the quantification of “clean water supply”.
To test the performance of the framework, a case study was carried out in the Goulburn River catchment, Australia, over the period of July 1st, 2023, and June 30th, 2024. Preliminary results show the potential of combing hydrological assessments with detailed data on water usage, water quality and technical constraints to better support water management and decision making. Furthermore, we found that of the total storage of 3.67 km3 available at the start of the period, roughly 50 % (1.88 km3) were either left unused or unclaimed at throughout the period. Of this, 0.09 km3 (5%) were removed to account for losses due to evapotranspiration. Next, a total volume of 1.73 km3 (92%) in the form of carryover rights and storage requirements were removed from the assessment, resulting in a mere 0.06 km3 (3%) of the remaining water were categorized as “Available clean water supply”. While this suggest that there is a misconception of clean water supply in the Goulburn River catchment, more importantly the result of the assessment suggests that the framework to a great extent can be used to assess a wide range of technical, qualitative, and managerial constraints, while at the same time tracking water usage. This combined with the possibility to adjust both the spatial and the temporal aspects, suggest that the framework could be useful for clean water supply calculations throughout multiple regions around the world.
How to cite: Bjerkén, A., Svensson, J., Alsterberg, C., and van Vliet, M. T. H.: A new framework for assessing clean water supply, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15712, https://doi.org/10.5194/egusphere-egu25-15712, 2025.
Water appropriation for human use can have significant impacts on the functioning of freshwater ecosystems. Reducing water appropriation can be a first step towards increasing water resilience and adapting to climate change, and it is therefore important to understand its spatial and sectorial distribution. In this contribution, we analyze the level of water appropriation in European watersheds, using available estimates of water demand and water availability.
We map an indicator of the level of appropriation of blue water in European river basins by broad water-using sectors, namely irrigation, livestock breeding, public (domestic) supply, the industry and thermal power plant cooling for energy generation. Water demand in a river basin may often represent 10-50% of renewable water availability and, in some regions, it may even exceed 100%, implying that either non-renewable water or transfers of water among river basins are needed.
The analysis shows that the level of water appropriation varies significantly across Europe, generally with a north-south gradient as expected, obviously reflecting the interplay between demand and availability. There is also a significant variability in the patterns of potential appropriation among sectors. In general terms, irrigation, systematically occurring in highly appropriated river basins, tends to be the main driver of water appropriation. Livestock demand is quantitatively less relevant at European scale, but occurs in relatively highly appropriated river basins as well. Energy represents the second most significant driver of appropriation, but tends to occur in less appropriated river basins. Most regions in central Europe show relatively uniform mixes of water demand, with no single sector taking the lion’s share of water appropriation, whereas the dominance of certain sectors, generally energy or irrigation, emerges in many northern as well as southern regions. The trend in water availability that can be anticipated on the basis of available climate projections will exacerbate the current situation particularly for irrigation and livestock.
Based on estimated volumes of domestic wastewater that can be reused for agricultural irrigation, we show how water reuse may substantially help reduce water appropriation in Europe. In general, we show that there is a widespread potential for reuse of water across sectors, that could be further analysed taking into account also other factors (particularly on water quality). Reducing water appropriation by water reuse after achieving efficient water use through appropriate management (“efficiency first”) may contribute substantially to water resilience.
How to cite: Pistocchi, A., Bisselink, B., Moschini, F., quaranta, E., trichakis, Y., bouaoui, F., grizzetti, B., hidalgo gonzalez, I., and zal, N.: Human freshwater appropriation in Europe: patterns and resilience prospects, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20604, https://doi.org/10.5194/egusphere-egu25-20604, 2025.
The Panama Canal is a critical waterway for international maritime trade. The canal's operations rely heavily on Gatun Lake, a 425 km² reservoir situated approximately 26 m above sea level, which supplies the water required for its lock system. Each lockage consumes 50 to 120 million gallons (0.19 to 0.45 hm3) of water, with 32 to 36 lockages typically occurring daily. Gatun Lake also provides drinking water to about half of the metropolitan population in Panama. Over the past decade, Gatun Lake's water levels have been significantly impacted by three major droughts, raising concerns about the Panama Canal's reliability for shipping traffic. Modelling inflows to Gatun is essential for assessing the impacts of climate change on its water level as well as developing robust management strategies. To this end, hydrological models of three major representative sub-catchments contributing to Gatun Lake were developed using HEC-HMS and future scenarios were simulated using climate projections from CMIP6. Results show a projected decrease in mean annual flow of 10% to 25% with respect to historical conditions for two out of the three sub-catchments studied.
How to cite: Castrellon, M. G., Trotman, J., Singamong, H., Jonoski, A., and Popescu, I.: Assessment of climate change impact on the inflows to Gatun Lake, Panama , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19078, https://doi.org/10.5194/egusphere-egu25-19078, 2025.
In an era of rapid climate change, the need for reliable information to support adaptation has never been greater. Changes resulting from warming temperatures and shifting precipitation patterns are influencing snowmelt dynamics, freeze-thaw cycles and basin response. These shifts may transform Canada’s environmental systems in profound and unprecedented ways. The Global Water Futures modelling research was developed to address these evolving challenges, providing insights into how Canada’s major river basins may respond to these changes. This work focuses on the pan-Canadian application of the MESH land-surface hydrology model across the Yukon, Fraser, Columbia, Mackenzie, Nelson, Churchill, Great Lakes-Saint Lawrence, and Saint John Basins, covering more than 5 million square kilometres. The model simulations integrate bias-corrected, downscaled climate projections to explore future scenarios. We detail the innovative workflows and tools developed for this research and present key findings on glacier retreat, permafrost thaw, and shifting river flow regimes. These results underscore the critical need for adaptive, forward-thinking water resource management to build resilience and strengthen the adaptive capacity of Canada’s watersheds.
How to cite: Pietroniro, A. and Pomeroy, J.: Evaluating Changes in River Systems and the Cryosphere in Canada: Insights from the Global Water Futures Modeling Synthesis, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14495, https://doi.org/10.5194/egusphere-egu25-14495, 2025.
The high stakes surrounding the availability of water resources under future climate raise the need to make relevant climate-water projections available to water managers. However, beyond this information, there is also the need to account for water management current practices and future needs in terms of adapting operations to balance water availability and demand under future climate and water use pressures. This isparticularly the case when dealing with reservoirs and their ability to regulate floods and droughts.
This study aims at setting up a full modelling chain, from climate to reservoirs management, to address water availability and operational management needs under future climate and water demand conditions. Our case study is the Seine River basin in France and its four upstream reservoirs which are operated to regulate flows up to the city of Paris. We first co-designed with stakeholders the “what-if” scenarios to investigate, combining possible future climate and management states. We then set up a simplified modelling approach to allow us to address the stakeholder’s needs. This modelling framework relies on a semi-distributed rainfall-runoff model, coupled to different management scenarios (reservoir rule curves) and forced by contrasted climate projections. The model was calibrated and validated using historical climate, hydrological and reservoir operation datasets, while also relying on stakeholder consultation. The relevance of current reservoir management operations in a future climate where the intensity and frequency of low flows might increase was investigated. We used the results of the national EXPLORE2 project, which downscaled 17 pairs of RCM/GCMs from CMIP5 over France. We used the outputs of the national EXPLORE2 project, which downscaled 17 pairs of RCM/GCMs from CMIP5 over France.
Our results show that the modelling framework accurately reproduces the relative influence of the reservoirs on the downstream discharges over the historical period. The influence on low-flow support is on average around 15%, with a maximum influence that can reach up to 50% during summer and downstream up to Paris. We also show that this can be a good indicator to quantify the influence of reservoir management on low flow conditions under future climate.
This work received funding from the Horizon Europe under grant agreement No. 101059372 (STARS4Water project).
How to cite: Collignan, J., Ramos, M.-H., de Lavenne, A., Barbé, C., and Riboust, P.: Assessing water management vulnerability under future climate scenarios: the case of the reservoirs in the Seine River basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8618, https://doi.org/10.5194/egusphere-egu25-8618, 2025.
Lake Victoria, the world’s second-largest freshwater lake, is vital for regional ecosystems and the livelihoods of millions across East Africa. However, the basin is increasingly vulnerable to hydroclimatic extremes, such as floods and droughts, exacerbated by climate variability and human activities. This research aims to address these challenges through the development and application of a Inland Lakes Integrated Water Balance Model (ILIWaB Model) for the lake. The ILIWaB Model, which has been successfully developed, integrates hydrological, meteorological, and socioeconomic data to simulate lake inflows, outflows, and net balances. The model serves as a foundation for flood simulations and climate projections, with the latter performed under a suite of Shared Socioeconomic Pathways (SSPs) to capture diverse future scenarios. Key outputs include flood extent simulations, scheduled for completion by May 2025, and the assessment of risks to surrounding populations. These simulations aim to predict the intensity and frequency of flooding events and evaluate their implications for population safety, infrastructure, and economic stability. Preliminary results demonstrate the model’s capability to accurately replicate historical water balance conditions and predict potential flooding hotspots. Long-term projections suggest a significant increase in flood risks under high-emission scenarios, threatening over 5 million residents in low-lying areas. The study underscores the importance of adopting adaptive management strategies and informed policymaking to mitigate future risks. This research offers a robust framework for climate-resilient planning in the Lake Victoria basin and provides transferable insights for other transboundary water systems globally.
How to cite: Ogembo, V., Thiery, W., Pietroiusti, R., Akurut, M., Vanderkelen, I., and Akinyi, G.: Hydroclimatic Modeling of Lake Victoria: Development of an Inland Lakes Integrated Water Balance Model with Future Climatic Risk Projections, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-600, https://doi.org/10.5194/egusphere-egu25-600, 2025.
River intermittence is a pivotal characteristic of freshwater systems and holds substantial ecological importance. The alteration of river intermittence due to climate change has raised concerns and has been primarily studied based on changing meteorological conditions. However, the mediating effects of groundwater and the influence of anthropogenic activities induced by climate change remain insufficiently explored.
This study quantitatively assessed the changes in river intermittence under different Shared Socioeconomic Pathways (SSP126, SSP370, SSP585) through the coupling of a fully distributed hydrological model (mHM) and a groundwater model (MODFLOW) up to the 2100s. The methodology was applied to the Bode catchment (3200 km²) in central Germany, one of the driest regions of the country. We evaluated the model from 2000-2024 using the observed data. We investigated the effects of the delayed response of the groundwater table on river intermittency using the inverse Fourier transform of the recharge. Additionally, we examined the impact of increased groundwater extraction on river persistence.
The results indicate that, compared to the reference period (2000–2014), the total active river network is projected to contract by 9.6%, 6.9%, and 3.8% under the SSP585, SSP370 and SSP126 pathways, respectively, by the 2080s. Additionally, the duration when the wetted fraction falls below the mean value of the reference period is expected to increase by 48 days under the SSP126 pathway and by 101 days under the SSP585 pathway in the 2080s. The impact of groundwater recharge delay predominantly affects transient small streams, particularly those experiencing changes in river-groundwater flow direction, with the magnitude of this effect varying based on their distance to the river. While climate-induced drying poses a notable challenge, water extraction is expected to have a more pronounced effect on local stream persistence, albeit within a restricted spatial range.
How to cite: Li, Y., Jomaa, S., Lischeid, G., and Rode, M.: The response of river intermittence to projected climate change and associated anthropogenic adaptations , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19216, https://doi.org/10.5194/egusphere-egu25-19216, 2025.
Climate change is expected to raise groundwater temperatures, affecting more than 100 million people living in areas where temperatures exceed national drinking water standards. However, many of these projections are based on models rather than observations. As more countries implement continuous monitoring programs for the sustainable management of groundwater systems, analyzing trends in water level and quality data related to climate change is becoming more feasible. Therefore, the goal of this study was to utilize a 30-year record of water level and water quality data collected from 1,600 wells drilled into the unconfined and unconsolidated coastal aquifer of Israel. We sought to identify trends in groundwater warming and explore their potential sources. High temperatures were generally related to wells in urban areas, while temperatures were lower under open fields and agricultural areas. However, the increasing trend in groundwater temperature was clear in both areas. We will investigate the correlation between well temperature and unsaturated zone thickness using well logs, and analyze temperature changes with distance from the Mediterranean Sea. Major ion data and a Piper diagram will be used to assess shifts in concentrations related to temperature changes. Although in its infancy, this study would shed light on some groundwater geochemical processes impacted by climate change.
How to cite: Turkeltaub, T. and Bernstein, A.: Determining the causes of groundwater warming and its effects on groundwater quality in Israel's coastal aquifer, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15127, https://doi.org/10.5194/egusphere-egu25-15127, 2025.
I represent a community catchment-based adaptation initiative launched in a peripheral region. The region is located in south-eastern Hungary (and its neighbouring area in Romania), in the floodplain between the Sebes-Körös river and the Fekete-Körös river. The initiative has been recently launched by 9 Hungarian and 3 Romanian local authorities to prevent the area from drying out.
The problem started with river regulation and drainage, followed by land use based on drainage for intensive agricultural production. Then in the 1970’s additional cross collecting canals (parallel tot he border) were created that constantly drain the waters of former natural watercourses into the surrounding larger rivers. Another problem is that run-off water that collects or flows into agricultural areas is immediately drained by farmers and water management institutions and there is no water retention in agricultural areas. These have led to the drying out of the area. All these human stresses are amplified by climate change. The amount of rainfall is decreasing, the number of rainy days is decreasing and their distribution is becoming more unpredictable. At the same time there are more intense rainfall events, during which rainwater do not infiltrate into the soil and does not improve the local water balance but runs off quickly from the area. Inland excess water inundation periods are also becoming less frequent and shorter in duration. Former watercourses and the current canals have dried up. Not only has the water disappeared from the watercourses, but the groundwater table has also dropped.
The catchment-based community started to assess the impacts of water scarcity due to climate change and poor water management and started to engage key stakeholders. The following steps are planned:
- Change the agricultural and landscape profile to be able to retain water. This includes the introduction of agricultural practices, green landscape elements and naturalwater retention measures and that can slow down runoff and improve infiltration.
- Modify the functioning of the canals that run through and drain the region to be able to collect and retain water.
- Improve water governance practices between the Hungarian and Romanian water management authorities so that water resources are more evenly distributed and balanced both spatially and in time.
- Develop an organizational model that can manage sub-catchment water resources to reduce vulnerability to climate change.
We would like to present the preliminary impacts assessed,, the options for intervention and the possibilities for further action.
How to cite: Vaszkó, C.: Climate change adaptation of the Bihor-Kis-Sárrét region through local catchment community initiatives to improve transboundary water governance and introduce natural water retention measures., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2376, https://doi.org/10.5194/egusphere-egu25-2376, 2025.
The Atrato River Basin, a critical hydrological resource in Colombia, is increasingly vulnerable to the dual impacts of extreme precipitation events and water scarcity, driven by climate change. This study aims to evaluate the potential impacts of climate change on hydrometeorological and river hydrological extremes in the basin, focusing on short-duration precipitation, peak river discharges, and low-flow conditions. Using state-of-the-art CMIP6 global climate models (GCMs) and four Shared Socioeconomic Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5), daily precipitation and temperature projections are statistically and temporally downscaled. In addition, intensity, duration and frequency for historical and future scenarios were assessed. Hydrological modeling using conceptual models quantifies the impacts of projected changes on river flow extremes. This research highlights the urgent need for adaptive strategies, including infrastructure upgrades and integrated water resource management, to mitigate climate-induced risks in the Atrato River Basin. It underscores the importance of robust uncertainty quantification for effective climate adaptation planning.
How to cite: Montenegro Gambini, J. I., Pachón Pitalúa, L. E., and Carrasco Carrasco, F.: Assessment of future changes on hydrometeorological and river flow extremes in the Atrato river basin under CMIP6 scenarios, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19843, https://doi.org/10.5194/egusphere-egu25-19843, 2025.
The selection of an appropriate reference period for determining the hydrological characteristics in Slovakia is of the utmost priority, particularly in the light of the observed changes in the hydrological regime of the watercourses in the last decades, since the last valid reference period 1961-2000 was established. We have analyzed the long-term discharge data from 113 water-gauging stations, to assess the deviations in moving averages of mean annual flows over 10-, 20-, 30-, 40-, and 50-year long periods.
Based on the results of comparison against the long-term mean annual flow values for the selected reference periods 1961-2000 and 1961-2020, we recommend considering the length of 30- to 40-years for the future reference period for hydrological applications. It is also important that the selected representative period will include the period after the year 2000.
We emphasize the need for further analysis of other hydrological characteristics, particularly in the area of the low flows, before finalizing the future reference period, as the dry periods after the year 2000 may lead to lowering the limits connected with minimum discharges. This may significantly affect sectors like water planning, water use, waste-water treatment, irrigation, nuclear reactor cooling, reservoir management, etc. The transition to a new reference period for hydrological characteristics should involve a thorough professional discussion, along with an analysis of potential economic impacts.
How to cite: Jeneiova, K., Blaskovicova, L., Kotrikova, K., Melova, K., and Poorova, J.: Key Considerations in Choosing the Optimal Reference Period for Hydrological Applications in Slovakia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8506, https://doi.org/10.5194/egusphere-egu25-8506, 2025.
Water-induced natural disaster risks are one of the major challenges faced globally. With the intensification of climate change and human activities, water scarcity, frequent extreme precipitation events, and the increasing occurrence of drought and flood disasters have become significant risk factors threatening the sustainable development of regional economies and societies. The occurrence of water-related disasters is not only influenced by natural hazards but also closely linked to the exposure and vulnerability of socio-economic systems, demonstrating a high degree of complexity and multifactorial nature. The Guanzhong Plain, as an important economic zone and densely populated area in northwest China, faces severe water risk challenges, posing significant pressure on both regional economic development and ecological sustainability. Therefore, a systematic assessment of the spatiotemporal characteristics and driving factors of water risk in the Guanzhong Plain is not only crucial for addressing regional water security issues but also provides an important practical basis for developing scientific water resource management strategies. This study analyzes the spatiotemporal variations in precipitation and temperature in the Guanzhong Plain using long-term observational data from 14 meteorological stations. Subsequently, the spatiotemporal characteristics of extreme precipitation were examined using the RClimDex model, and the Standardized Precipitation Index (SPI) was calculated. In addition, the Remote Sensing Ecological Index (RSEI) was employed to assess the ecological environment status, revealing the spatiotemporal patterns of drought and flood hazards and their driving factors. Building on these analyses, a comprehensive water disaster risk assessment framework was developed, incorporating factors such as the hazard posed by disaster-inducing elements, the vulnerability of disaster-prone environments, the exposure of disaster-bearing entities, and the capacity for disaster prevention and mitigation. Sixteen representative indicators were selected, and a combined weighting approach using the Analytic Hierarchy Process and Entropy Weight Method was applied to assign weights to these indicators. Finally, a quantitative assessment and spatial zoning of water risk safety in the Guanzhong Plain were conducted using weighted composite analysis. Based on the identified levels of water risk safety, corresponding policy recommendations were proposed. This study systematically reveals the spatiotemporal evolution patterns and underlying driving mechanisms of water risk in the Guanzhong Plain, and develops a comprehensive water risk assessment framework, providing scientific basis and theoretical support for regional water resource management and sustainable development.
How to cite: Li, X.: Spatiotemporal Analysis of Driving Factors and Comprehensive Risk Assessment of Water-Induced Hazards in the Guanzhong Plain, Northwest China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1943, https://doi.org/10.5194/egusphere-egu25-1943, 2025.
Tropical regions are characterised by a high variance in precipitation and experience significant fluctuations in river discharge. These fluctuations in discharge play a dominant role in shaping environmental flow (EF), which is vital for the survival of river ecosystem. However, EF assessment has never been made mandatory for water infrastructure construction and water withdrawal activities in some of the developing countries, including Malaysia. This, in the future, may lead to the severe disturbance of the river ecosystem due to the positive human population growth that requires more needs for water.
Estimation from global EF can be referred to; however, it was found to have a poor correlation with local estimates; thus, the assessment needs to be conducted locally. Besides, the determination of EF for ungauged basins is still considered a difficult problem. Most frequently, hydrological modelling is used for this purpose prior to any further calculation. Thus, through this study, we aim to determine if there are consistent relationships in EF requirements across different basin sizes that will assist in scalable management strategies.
The hydrology-based method introduced by Smakhtin and Anputhas (IWMI, 2006) was selected to calculate EF requirements at 62 sites in Malaysia with available observed records for more than 20 years. The results showed that, on average, 43% of the annual discharge was needed by the river to sustain its ecology, with the assumption that the basins are maintained in fair conditions. In the most regulated conditions, at least 20% of the annual discharge needs to be reserved to maintain the function of rivers as water bodies where, in this case, the ecosystem has significantly modified. We also found that the basin area well corresponds to the discharge and EF with a determination coefficient higher than 0.95. Therefore, it can be acknowledged that the suggested equation (0.0146 × basin area in km2 + 2.90) may be used for determining EF in any river reach in the tropical regions, especially Malaysia.
The estimated EF corresponding to basin management serves as a preliminary basis for sustaining river ecosystem. Overall, our study provides a reference for water practitioners and policymakers, especially for the rapid judgement on the quantity of water resources that need to be conserved.
How to cite: Mohamad Arbai, N. A. and Irie, M.: Estimations of environmental flow requirements in a tropical region, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19980, https://doi.org/10.5194/egusphere-egu25-19980, 2025.
The hydrological processes of the Nu-Salween River (NSR) Basin are increasingly challenged by climate change in the 21st century. Effective water resources management, particularly reservoir regulation, plays a key role in flood control and drought mitigation. This study employs the Geomorphology-Based Hydrological Model of the NSR Basin (GBHM-NSR), incorporating a reservoir regulation scheme for simulating the impact of a hypothesized reservoir, to: 1) assess the trends of flooding and drought under future climate change scenarios across the NSR Basin, and 2) evaluate the possible impact of reservoir regulation on the frequency and magnitude of future flood and hydrological drought events. The results indicate an anticipated increase in both the frequency and magnitude of floods, alongside a decrease in drought risk under climate change. The midstream area is identified as particularly vulnerable to hydrological anomalies. Reservoir regulation serves to stabilize intra-annual streamflow, mitigating both flood and hydrological drought risks in the future under three SSP-RCP scenarios, with the most pronounced effects observed under the SSP2-RCP4.5 scenario, indicating the reservoir regulation scheme is of greater effectiveness under the future scenario with continuing pathways as present condition. However, in the future scenario with higher severity of climate change and hydrological extremities (SSP5-RCP8.5), more targeted and strengthened regulatory strategies will be necessary to achieve better water security for riparian communities and maintain hydrological stability, both of which are essential for sustaining ecosystem services, supporting socioeconomic development, and adapting to climate variability.
How to cite: Guo, Y., Yang, F., and Lu, H.: The mitigation on future flood and hydrological drought under reservoir regulation: A case study in Nu-Salween river basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3264, https://doi.org/10.5194/egusphere-egu25-3264, 2025.
Atmospheric climate change in cold regions can impact groundwater resources through alterations to snow-rain partitioning, mid-winter thaws, and evapotranspiration. Also, sea-level rise can drive elevated coastal water tables and saltwater intrusion, which can deleteriously impact coastal groundwater resources and coastal infrastructure. We investigate these processes in the coastal province of Nova Scotia, Canada, where 40% of the population relies on vulnerable private wells. We consider impacts of past climate change by conducting statistical analyses of hydrometeorological data and find that late-summer significant negative trends are apparent in net precipitation, groundwater levels, and groundwater discharge (baseflow). To assess the impacts of future climate change we are developing province-wide coastal groundwater vulnerability maps (salinization and water table rise) based on a coastal groundwater analytical solution parameterized and forced with geospatial data. We are also using downscaled climate projections to drive a physically-based hydrologic model to investigate how groundwater recharge may respond to changing temperature and precipitation in different hydrologic response units. Our preliminary results provide critical insights into the impacts of climate change on groundwater resources and lay the foundation for better risk identification to underpin sustainable groundwater management.
How to cite: Kurylyk, B., LeRoux, N., Berry, H. B., Motamedi, A., Strong, R. B., and Malley, R.: Influence of past and future atmospheric and oceanic climate change on groundwater levels, recharge, discharge, and salinity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7423, https://doi.org/10.5194/egusphere-egu25-7423, 2025.
The main source of drinking water in Slovakia is groundwater, with about 80% of the water used for public supply coming from groundwater reserves. In Slovakia, we have areas that are supplied with drinking water from surface water trapped in water reservoirs such as, for example, water reservoir Starina in the east part of Slovakia, Nová Bystrica reservoir in the north of Slovakia, and in the south of the central part of Slovakia is Hriňová reservoir. In 2022, 83% of drinking water was sourced from groundwater abstractions and 17% from surface water abstractions. These abstractions are processed and evaluated as part of Slovakia’s water resource balance at the river basin level. We analyzed annual abstraction data for individual districts based on the intended use of the water. The data were examined over 10 years (2011–2021), using long-term average values for each district and sector (e.g., public water system supply, agriculture, and industry), and compared with consumption data for 2022. The increase or decrease in groundwater abstractions was then evaluated. The year 2022 was selected for analysis due to its classification as a dry year, characterized by low precipitation and runoff. The analysis results are presented in a map that shows surface and groundwater abstractions across Slovakia.
The analysis indicates that, in the dry year of 2022, 51% of surface and groundwater abstractions were used for public water supply systems, 5% for industrial purposes, and 44% for agricultural needs. Of the groundwater abstractions, 72% were allocated to public water supply, 4% to agriculture, and 24% to industry. On the other hand, the surface water abstractions were distributed as follows: 21% for public water supply, 6% for agriculture, and 73% for industrial purposes. Compared to the period from 2011 to 2021, there was a 6% increase in groundwater abstractions in 2022 (with a 3% increase for public water supply systems, a 14% increase for agriculture, and a 14% decrease for industry).
Acknowledgement
This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-23-0332.
How to cite: Kotrikova, K. and Slivova, V.: Analysis of the surface water and groundwater abstractions for the public water supply, agricultural and industrial purposes in the period 2012-2021 in comparison to 2022 , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9128, https://doi.org/10.5194/egusphere-egu25-9128, 2025.
Hydrological monitoring of daily discharge since 1966 in a small agricultural catchment of the Mławka River of 66.2 km2, located in the macro-region of the North Mazovian Lowland, which is central part of the Vistula River basin, have shown a progressive decrease in renewable water resources in the considered multiannual periods of 1966–1990 and 1991–2020. With a similar mean annual precipitation of about 565 mm in both multiannual periods, the mean annual discharge decreased by 15.6%, i.e. from 171 mm to 144 mm, respectively in 1966–1990 and 1991–2020. This corresponds to mean flow (SSQ) in the multiannual periods of 358 and 0.302 m3·s–1, respectively. The runoff coefficient decreased from 0.303 to 0.265. Recent data, of the hydrological years 2021-2024, confirm the decrease in renewable water resources.
This may be attributed to the increased evapotranspiration caused both by an increase in the mean annual air temperature (by about 0.30°C per 10 years in 1951–2020) in the region and an increase in the proportion of forested land in the catchment by about 10% (from 23% to 33%) at the expense of arable land.
The low flows in the considered multiannual periods, characterised by the mean flow from annual minimums (SNQ), decreased even more significantly by 29.1%, i.e. from 0.147 to 0.104 m3 s–1.
How to cite: Banasik, K., Kierasiński, B., Karpińska, K., and Więzik, B.: Long term changes of river flow from a small agricultural catchment in the center of Poland, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16378, https://doi.org/10.5194/egusphere-egu25-16378, 2025.
Water resources and ecosystems in volcanic islands frequently exhibit significant vulnerability to water contamination from anthropogenic or natural sources, seawater intrusion, or freshwater scarcity. This vulnerability stems from the typically limited water storage capacity and the reduced recharge and volume of freshwater bodies. In the south of Gran Canaria Island (Canary Islands, Spain) is found the Maspalomas Coastal Dune Field Natural Reserve, a protected and unique aeolian landscape and ecosystem in Europe. Within this coastal dune system, a lagoon is found, whose ecosystem survival is highly dependent on salinity, pH, oxygenation, and organic matter content, as well as processes of evaporation, anoxia (lack of oxygen), and eutrophication. Furthermore, the projected sea level rise according to the IPCC within the next 100 years could enhance seawater intrusion into the freshwater aquifer that feeds the lagoon.
A reactive transport model has been performed in the context of the European project NATALIE, using the code PHAST to assess the potential effect of enhanced seawater intrusion into the Maspalomas lagoon. The model was implemented through a 2D mesh representing the lagoon formed in a unit of aeolian sands. Two water samples of the lagoon and seawater were used as input solutions and the sea level rise up to 1 m was simulated, displacing the mixing zone up to 10 m inland. The evolution of saturation indices (SI) of calcite, gypsum and halite and the chemical reactions of pH buffering and mineral precipitation in the lagoon were implemented in PHREEQC and introduced in the PHAST model. The simulation showed that a seawater fraction up to 72 % could be reached by mixing with the freshwater feeding the Maspalomas lagoon. This enhanced intrusion could lead to electrical conductivities (EC) up to 38,000 µS/cm, and neutral to alkaline pH up to 7.8, conditions to which several present acuatic plants as Juncus acutus and Tetraena fontanesii are not adapted. Besides, with seawater fractions over 65 % the lagoon reached oversaturation in calcite and was close to oversaturation in gypsum and halite, whose precipitation could affect the hydraulic properties of the connection between the lagoon and the shallow aquifer. A managed periodical freshwater recharge of the lagoon with urban runoff through SUDS (Sustainable Urban Drainage Systems) is proposed as part of the tasks of the European project NATALIE.
How to cite: Jiménez, J., Marazuela, M. Á., Baquedano, C., Martínez-León, J., Gasco, S., Sariago, R., Santamarta, J. C., and García-Gil, A.: Predicting the hydrochemical impacts of sea level rise and intrusion in the lagoon ecosystem of the Maspalomas coastal dune field Natural Reserve (Gran Canaria, Spain) through reactive transport modelling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17529, https://doi.org/10.5194/egusphere-egu25-17529, 2025.
Natural discharges are crucial for the quantitative assessment and sustainable management of water resources, enabling the assessment and prediction of water availability and the impact of climate change. The aim of this study is to present a simple methodology for the reconstruction of natural discharges and identify direct and indirect withdrawals. It is based on groundwater recharge and runoff data provided from the BIGBANG v.6 database (ISPRA), which collects national-scale maps of the main hydrological variables in the period 1951-2022. Specifically, the framework is based on the calibration of three parameters, which are (i) the infiltration coefficient, (ii) the ratio between the hydrogeological and catchment area and (iii) storage coefficient of the linear reservoir model. The procedure was applied to the Tiber River basin, closed at the Ripetta station. This methodology enables the reconstruction of long natural flow time series at monthly scale, which are fundamental to catchment and water resource management policy. Furthermore, the methodology is able to effectively identify dynamic differences between surface and subsurface flows. The results demonstrate the procedure's high accuracy in reproducing natural flow rates, with minimal errors. The developed approach provides a valuable tool for watershed-scale water resource management, supporting policy planning, evaluation, and implementation.
How to cite: Pomarico, I., Volpi, E., Zarlenga, A., and Fiori, A.: Reconstruction of a long series of Natural Discharges: an application to the Tiber River basin, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20674, https://doi.org/10.5194/egusphere-egu25-20674, 2025.
Posters virtual: Thu, 1 May, 14:00–15:45 | vPoster spot A
EGU25-7025 | ECS | Posters virtual | VPS10
Assessment of climate change-water resources interaction by different modelsThu, 01 May, 14:00–15:45 (CEST) | vPA.7
Climate change significantly impacts water quality and quantity, intensifying extreme weather events, such as floods, droughts, and heat waves. Rising temperatures can increase humidity and dryness, disrupt the water cycle, cause saltwater intrusion into upstream lakes due to sea-level rise, and reduce dissolved oxygen in rivers, thereby deteriorating freshwater quality. Thus, accurate prediction of key climate variables, such as precipitation and temperature, is essential for mitigating detrimental impacts. This study evaluates three modeling approaches, including Process-Based (PB) models, Deep Learning (DL) models, and Process-Based Deep Learning (PBDL) models, to highlight their strengths and limitations.
Our assessment shows that PB models, which are based on physical laws and account for complex interactions between the atmosphere, land, and water bodies, require high parameterization and computational simplifications, which can lead to inaccurate results. DL models can uncover complex relationships from large datasets. They are effective in co-predicting variables, simulating General Circulation Model (GCM) outputs, optimizing PB models, and filling spatiotemporal data gaps. However, their performance depends on the availability of extensive temporal-spatial data, particularly for extreme events. The other group, PBDL models, known as physics-informed or hybrid models, can integrate the strengths of PB and DL approaches. Indeed, these models consider physical laws, such as mass balance and energy conservation, while leveraging DL's pattern recognition capabilities. Even with limited data, these models achieve superior predictions by combining pre-trained PB model outputs, which reduces computational demands.
Although these methods are used to evaluate (actual) evapotranspiration, snowmelt rate, soil permeability, hydraulic conductivity, and the effect of a warming climate on water temperature and streamflow, the interconnected influences on water systems, especially water quality indicators such as dissolved oxygen, heavy metals, nutrients, and water clarity, remain underexplored, presenting a critical research gap. Findings confirm that incorporating simultaneous predictions from DL models with proper variable selection and hyperparameter tuning can further enhance model robustness. Advancing PBDL models through integrating well-calibrated hydrological models, expanding spatiotemporal data coverage, and improving measurement accuracy yields more reliable climate change predictions and bolsters sustainable water resource management strategies.
To identify promising solutions, researchers are encouraged to address the non-stationary behavior of natural systems, considering not only meteorological factors (e.g., wind speed and solar radiation) but also the compound impacts of anthropogenic climate change on water resources. Additionally, selecting appropriate models and coupling them can improve an overall understanding of climate and water system interactions.
How to cite: Karimnejad, A., khorashadi zadeh, F., and Moghim, S.: Assessment of climate change-water resources interaction by different models , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7025, https://doi.org/10.5194/egusphere-egu25-7025, 2025.
EGU25-12004 | Posters virtual | VPS10
A Framework for Assessing Water Availability and Risk of Reservoirs in Taiwan under Climate ChangeThu, 01 May, 14:00–15:45 (CEST) | vPA.8
Taiwan plays a crucial role in the global supply chain as a major semiconductor manufacturer. Semiconductor production depends heavily on water resources, making the stable supply of industrial water from upstream reservoirs essential to maintaining the global supply chain. However, international water risk assessments often fail to capture Taiwan’s regional hydrological variations due to their large spatial scale, obscuring the real physical and financial risks related to water resources under climate change. Given Taiwan's distinct climate with pronounced wet and dry seasons, short and fast-flowing rivers, and limited surface water retention, reservoirs are critical for regulating water supply. This study employs hydrological models and reservoir operational models to develop a reservoir risk assessment framework, which is the foundation of water resource management. The assessment procedure aids in understanding regional climate-related water risks. Utilizing this assessment tool to adjust reservoir operations will offer strategies for rational water resource management and enhanced climate resilience.
How to cite: Lai, Y.-P. and Lee, T.-Y.: A Framework for Assessing Water Availability and Risk of Reservoirs in Taiwan under Climate Change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12004, https://doi.org/10.5194/egusphere-egu25-12004, 2025.
