PICO
This session welcomes studies on non-conventional water resources spanning technical, socio-economic and political disciplines. More specifically, we accept contributions including, but not limited to:
● innovative methods to design, monitor and assess NCW;
● social, economic, environmental and cultural sustainability of NCW water use;
● good practice examples for NCW solutions implementation;
● global and local drivers and barriers to NCW implementation
● technical innovations in harvesting, storing, treating, and using NCW, and innovation valorization and transfer;
● Stakeholder engagement and multi-actor platforms for NCW planning and implementation
Co-organized by the IAHS Working Group on “Non-Conventional Water Use for Integrated Water Resources Management” of the International Association of Hydrological Sciences: https://iahs.info/Initiatives/Scientific-Decades/helping-working-groups/non-conventional-water-ncw-use-for-integrated-water-resources-management/
Although the natural water system and urban water cycle are traditionally considered as separate domains, they are physically strongly connected. The hydrological system supplies water for anthropogenic use, and after use and treatment, wastewater is released from the urban water cycle back to the natural water system. Yet within the broad range of adaptation measures aimed at improving regional water availability, solutions that intentionally leverage these linkages remain underexplored. Exploitation of non-conventional water resources – such as industrial of domestic wastewater – is only recently being explored in temperate climates like in the Netherlands, as a complement to traditional groundwater and surface water supplies. Embracing such circular approaches, instead of the prevailing linear practice in which water is quickly discharged from an area, offers new opportunities for more balanced water allocation to protect the environment that depends so heavily on water resources.
We present examples in which the benefits and risks of cross-sectoral measures have been assessed. These include a brewery initiative in the southern Netherlands applying treated industrial wastewater for subsurface irrigation to reduce agricultural drought stress, the reuse of domestic wastewater for industrial applications, and water reuse for drinking water production. Such approaches have the potential to alleviate pressure on water resources which could benefit other water-dependent functions. Our findings show that a system perspective and clear evaluation criteria are essential to quantify the real potential of such (cross-sectoral) approaches and to identify the propagation of the effects of using non-conventional sources through the regional water system, including associated trade-offs. For instance, determining what proportion of residual water can be used or reused for agricultural drought mitigation requires assessing net effects on other functions, such as nature. Across the examples, we find that the propagation of quantitative effects – both positive and negative – remains insufficiently explored.
We further show that while dedicated models can effectively assess subsystem responses, they may be inadequate when a broader, integrated perspective is needed. Water systems thinking and modelling are increasingly used to analyse complex dynamic water systems, including groundwater systems, and are helpful in studying multiple water uses and planning strategies. Tools as Sankey diagram visualizations, related causal loop diagrams, and resulting system dynamics modelling frameworks help explore the regional feasibility of water (re)use, its potential to reduce groundwater and surface water demand, and the possible synergies and trade-offs between sectors. Additionally, these tools can serve as communication frameworks to engage stakeholders and support users/policy makers in understanding all the interlinkages, benefits and trade-offs of measures. We illustrate these insights with case-study implementations.
How to cite: Bartholomeus, R. P., Stofberg, S. F., van Huijgevoort, M. H. J., Yazdani, M., de Wit, J. A., and Raat, K.: Regional impacts of non-conventional water use: the role of water-systems thinking and modelling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1735, https://doi.org/10.5194/egusphere-egu26-1735, 2026.
The EU council has stablished clear the goals to strengthen territorial climate change resilience and adaptation. In this context, water scarcity scenario is only one of several challenges. Extreme weather events such as heatwaves, heavy rainfall, floods, and droughts are becoming more frequent and intense across Europe. To address these issues NCW emerges as a solution that can be implemented through different technologies and budgets. The Horizon AWARD EU project Demo Cases Cities as Milan, Cyprus, Bucharest and Santiago de Compostela, in very different contexts, represent a rich example of the implementation of NCW solutions through the SuDS of the Sponge City project, the improvement of tertiary treatment in the WPPT, the NBS construction to level the shallow layer of the aquifer and feed the lakes in public parks, or building artificial ponds and NBS to treat the polluted water in industrial areas.
However the performance of a NCW solution can certainly be assessed, the technical aspect alone is not enough to make it a solution. It requires appropriation by stakeholders. It also emphasizes that the problem cannot be solved individually. A common approach is necessary, raising the question of the mobilization of actors in political processes, the collective learning, the exchange of points of view and the mobilization of scientific and expert knowledge, as well as collective decision-making. Knowledge is key in each situation for the implementation of NCW solutions. To support this, the DST-TSD platform proposes a method which includes diagnosis, vulnerability assessment, prospective exercise, and deliberation. The deliberative approach is adopted to encourage stakeholder participation in governance processes and their engagement in developing adaptation strategies.
While the performance of a NCW solution can certainly be assessed, the technical aspect alone is not enough to make it a solution. It requires appropriation by stakeholders. Even if takeholders may have an individual understanding of the situation, the problem definition is much broader and requires to consider the wide range of concerns raised by stakeholders. It also emphasizes that the problem cannot be solved individually. A common approach is necessary, thus raising the question of the mobilization of actors in political processes, the necessary collective learning, the exchange of points of view and the mobilization of scientific and expert knowledge, as well as collective decision-making. Knowledge is key in each situation for the implementation of NCW solutions. For this, the DST-TSD platform proposes a method which includes a diagnosis, a vulnerability assessment, a prospective exercise, and a deliberation matrix. The deliberative approach is adopted to encourage stakeholder participation in governance processes and their engagement in developing adaptation strategies.
How to cite: Perez, S., Douguet, J.-M., and Deladerriere, L.: The challenges for NCW governance in Europe: the need of a multi-scale and multi-actor approach to include NCW in strategic planning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21626, https://doi.org/10.5194/egusphere-egu26-21626, 2026.
The combined effects of climate change and demographic dynamics in the Mediterranean region are expected to exacerbate pressures on freshwater resources and to compromise the capacity of countries to ensure water supply security, defined as the sustained availability of sufficient quantities of safe and reliable water. These challenges will be particularly pronounced in urban catchments, characterized by low elevation, high population density, and hydrological systems that drain towards the sea. Mediterranean urban coastal catchments are especially vulnerable to water scarcity due to high water demand, limited inland freshwater availability, and increasing exposure to anthropogenic contamination from industrial, agricultural, and municipal sources, as well as to seawater intrusion, whereby saline water encroaches into freshwater aquifers, reducing their suitability for use. In this context, the Interreg NEXTMED RESWATER (Non-Conventional Water Resources for Resilient Urban Water Management) project targets critical urban water-demand hotspots and aims to identify trends in water resource availability and demand development to evaluate future risks in ensuring water supply security. RESWATER capitalizes on the results and methodologies developed in previous EU funded projects such as ARSINOE and NAWAMED, as well as on the ongoing NUSTALGIC project, ensuring continuity, knowledge transfer and upscaling of best practices in resilient urban water management. Within the RESWATER project, an online catalogue of decentralized Non-Conventional Water Resources solutions will be delivered, based on the experience gained in seven urban demonstration units, located one in each project partner country (i.e., Malta, Greece, Spain, Tunisia, Turkey, Egypt and Italy). This will form the basis for the development of a policy framework to support resilient Urban Water Management Plans, fostering continuous stakeholder engagement through local Living Labs and a regional Community of Practice. Together, these actions will constitute an integrated capacity building platform, to support policymakers, researchers, municipalities, water authorities, and citizens in the development of resilient cities.
How to cite: Cristiano, E., Viola, F., Deidda, R., Cutajar, A., Skondras, N., Kandarakis, A., Ben Said, M., Mellah, T., Beydağ, Y., and Sapiano, M.: Implementation of Non-Conventional Water Resources for Resilient Urban Water Management: insights from the RESWATER project , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6564, https://doi.org/10.5194/egusphere-egu26-6564, 2026.
Amid rapid urbanization and climate change, global urban water consumption, particularly household water use, has continuously increased in recent years. However, the impact of climate change on individual and household water use behavior remains insufficiently understood. In this study, we conducted tracking surveys in Beijing, China, to determine the correlation between climatic factors (e.g., temperature, precipitation, and wind) and household water use behaviors and consumption patterns. Furthermore, we proposed a genetic programming–based algorithm to identify and quantify key meteorological factors influencing household and personal water use. The results demonstrated that water use is mainly affected by temperature, particularly daily maximum (TASMAX) and minimum (TASMIN) near-surface air temperature. In addition, showering and personal cleaning account for the largest proportion of water use and are most affected by meteorological factors. For every 10℃ increase in TASMAX, showering water use nonlinearly increases by 3.46 L/d/person and total water use nonmonotonically increases by 1.14 L/d/person. When TASMIN varies between −10℃ and 0℃, a significant change in personal cleaning water use is observed. We further employed shared socioeconomic pathway scenarios of the Coupled Model Intercomparison Project 6 to forecast household water use. The results showed that residential water use in Beijing will increase by 21%–33% by 2035 compared with 2020. This study offers a groundbreaking perspective and transferable methodology for understanding the effects of climate change on household water use behavior, providing empirical foundations for developing sustainable water resource management strategies.
How to cite: Zhang, Y., Zhu, Y., Li, H., and Wang, L.: Quantifying the impact of climate change on household water use in mega cities: a case study of Beijing, China, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2078, https://doi.org/10.5194/egusphere-egu26-2078, 2026.
Rural coastal settlements located in hyperarid areas face increasing levels of water insecurity due to limited freshwater availability, the increasing demand by mining industry, and persistent gaps in water governance. In northern coastal Chile, there is a semi-permanent presence of fog, an unconventional water source with the potential to complement existing resources. However, it has not yet been incorporated into territorial planning and water management. Water is harvested using fog collectors and studies in the area mention average yield varies from 1.5 to 7 L/m2/day.
This research examines the current conditions of water supply institutional challenges, local perception, and the potential for fog water harvesting as a complementary resource in the town of Chanavaya, which has approximately 80 inhabitants. This coastal settlement is currently supplied exclusively by tanker trucks that deliver water to a Rural Sanitation System and to self-managed households. This mode of supply entails high operating and environmental costs and limits the volume of water available in the town (between 250 and 300 m3 a month), resulting in water insecurity for residents.
This study proposes a mixed methodological approach. From a social perspective, this research analyses the community's perception of current access to water, its main uses, the problems associated with the existing management model and its costs, knowledge about fog water, acceptance of this unconventional resource, and willingness to pay for it. The research also integrates a normative and institutional document review, interviews with water managers, and household surveys. An estimate of the collectable fog-water potential was also obtained using the numerical model AMARU.
The AMARU model enables the estimation of fog-water potential using meteorological data located at different altitudes, GOES satellite images and a Digital Elevation Model to identify where and how much fog water can be collected. For this research, three climate scenarios were used corresponding to superabundance (1998), mean (2016), and deficit (2019) in fog availability, according to ERA 5 climate reanalysis data. The estimated potential volumes are compared with current water supply, local demand and international standards for access to the resource. These results make it possible to quantify the contribution of this alternative source to reducing gaps in water access and availability.
Preliminary results indicate that fog harvesting could make a significant contribution to reducing dependence on water tankers, increasing water security and promoting domestic and productive activities. This research contributes to the assessment of fog use in human settlements. It represents a step towards water strategies that are resilient to climate change and created in collaboration with the community.
How to cite: Contreras, C., Carter, V., Espinoza, V., and del Río, C.: Fog water as a non-conventional resource for strengthening water security in coastal settlements of the Atacama Desert, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-750, https://doi.org/10.5194/egusphere-egu26-750, 2026.
The increasing reliance on desalinated water in water-scarce regions has raised concerns about its acceptance and perceived quality. This study aims to assess public perception and acceptance of desalinated water as drinking water in Agadir, Morocco, where it has been supplied since January 2022. The objective is to understand the challenges and opportunities of integrating desalinated water into the urban supply. A survey was conducted with 408 respondents using a questionnaire available in Arabic and French. It covered demographic information, evaluations of past and present drinking water quality, behavioral adaptations (such as using water filters or bottled water), perceived benefits and drawbacks of desalinated water, and the influence of social factors on its acceptance. Beyond the survey, this study includes water quality assessments across different districts of Agadir. These assessments aim to compare the quality of drinking water in various neighborhoods with that of desalinated water directly from the desalination plant. This approach seeks to provide objective data to support discussions about the acceptance and effectiveness of desalinated water as a sustainable solution. Preliminary results indicate that 69.2% of respondents perceive a decline in drinking water quality since the introduction of desalinated water, mainly due to changes in taste, odor, and clarity. Before January 2022, only 18% of respondents rated the water quality as good or very good, a perception that has significantly worsened. Additionally, 70% reported a deterioration in water quality. Regarding acceptance, 36% of respondents expressed reluctance or refusal to drink desalinated water. While some recognize its potential to reduce pressure on groundwater resources, concerns about cost, environmental impact, and organoleptic properties (taste, smell, and appearance) remain substantial barriers. Social and community influences also play a significant role in shaping opinions. The findings highlight the need for targeted awareness campaigns, strict quality control measures, and informed policy adjustments to build public trust in desalinated water. By presenting objective data on water quality and exploring public attitudes, this study provides valuable insights into the social dimensions of desalination projects. It emphasizes the importance of a strategic approach to integrating desalinated water into urban systems, addressing both public concerns and sustainable water resource management. This research contributes to broader discussions on sustainable water solutions.
How to cite: Aglagal, C., Hssaisoune, M., Ait Brahim, Y., Nouj, N., El Hafyani, M., Abahous, H., Gouahi, S., Chaaou, A., Ait El Kadi, M., Ait-Ichou, H., Taia, S., and Bouchaou, L.: Public Perception and Acceptance of Desalinated Water in Agadir, Morocco: Challenges and Opportunities for Sustainable Water Management, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-872, https://doi.org/10.5194/egusphere-egu26-872, 2026.
The intensifying global water crisis calls for novel strategies to ensure reliable, equitable, and sustainable water supply. As climate change, population growth, and overuse of conventional freshwater sources push water systems beyond safe planetary boundaries, novel technologies are becoming increasingly central to adaptation strategies. Desalination stands out as a critical yet contested option to enhance water security, particularly in regions exposed to persistent aridity and rising water stress. While technologically mature and rapidly expanding, future developemtn of large-scale desalination capacities remains underexamined as a potential source of maladaptation due to its high energy demand and potential carbon footprint.
Using the data on individual plants from Global Water Intelligence, in this study we provide a global assessment of the evolution and future prospects of desalination. Historical timeseries on capacities of key desalination technologies were combined with climate and socioeconomic indicators into a panel dataset to analyze historical growth patterns and project future trajectories under different Shared Socioeconomic Pathway (SSP) scenarios. Applying random forest regression models, we identified key predictors of national desalination capacity—namely water stress, aridity ,income, population, and urbanization—as drivers of observed and projected trends.
Historically, global desalination capacity expanded from about 250,000 m³/day in 1980 to 122 million m³/day by 2020. While dominated by high-income and arid countries in the past, desalination is projected to accelerate in developing regions—particularly Africa and South Asia—driven by population growth and rising economic activity. Cumulative capacity is projected to at least double (SSP3) or nearly triple (SSP1) by 2060. Scenario comparisons show that socioeconomic development, more than climate dynamics, shapes the scale of desalination dynamics.
To evaluate the emissions footprint of future desalination, we linked energy demand estimates (Magni et al., 2025) with scenario-based assumptions on growth in desalination capacity, including various technological compositions. We find that, owing to population- and economic activity-driven demand for desalinated water, in the scenario of high economic development but continued and increased fossil fuel emissions peak around the year 2070 at around 550 MtCO2/year, but they decrease only to around 400 MtCO2/year later in the century, which is still twice the current levels. In a fragmented development-high emissions scenario, emissions steadily rise to around 300 MtCO2/year in 2100. For a high development-fast decarbonization scenario, emissions from desalination become neutral past 2070.
Our findings highlight desalination’s dual role as both an enabler and potential risk in climate adaptation pathways. Scaling desalination as a sustainable non-conventioonal water (NCW) solution will require integrating renewable energy supply, technological innovation, and proactive governance to minimize maladaptive outcomes. This research informs global debates on water security by quantifying the balance between desalination’s adaptation benefits and its climate-related costs, emphasizing its role within equitable and low-carbon NCW portfolios.
How to cite: Andrijevic, M., Vinca, A., Jones, E., Magni, M., van Vliet, M., and Byers, E.: Projections of future desalination capacity and related risks of maladaptation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19600, https://doi.org/10.5194/egusphere-egu26-19600, 2026.
Water scarcity is tightening its grip on global agriculture as climate change advances, with the Mediterranean facing particular strain. About thirty percent of its 11.32 million hectares of irrigated land overlies saline aquifers, forcing farmers to depend on water of declining quality. Brackish water represents a viable substitute for freshwater, yet its adoption remains limited because current tools for assessing crop specific impacts often require detailed field measurements that are rarely available at regional scale. This study presents a simplified agro hydrological modelling framework designed for first level analysis of salinity effects on crops, soil, and irrigation demand. It operates with a small collection of standard inputs, including climate, soil properties, and irrigation water salinity, allowing consistent application across large areas. The framework is applied to twenty four crops across the Mediterranean under four irrigation strategies: freshwater baseline, brackish water only, brackish water with leaching, and mixed irrigation adjusted to maintain soil salinity at half of each crop’s tolerance level. Across regions influenced by saline aquifers, the leaching based strategy cuts freshwater use by seventy six percent compared with the freshwater baseline, while still maintaining soil salinity within acceptable crop thresholds. At the basin scale, mixed irrigation shows a total water demand of 33.68 cubic kilometres per year with limited salinity stress, providing an effective balance between freshwater conservation and soil protection. Field-level simulations for the Zelba area in Tunisia, using brackish water of 7.2 dS per metre for wheat, barley, and sorghum, confirm the strong performance of management strategies that pair brackish water with targeted leaching. This scalable approach provides rapid and reliable insight into the feasibility of brackish water use, helping farmers and policymakers evaluate irrigation options, protect soil quality, and plan freshwater savings in water-scarce environments.
How to cite: Nanesha, H., Rulli, M. C., and Chiarelli, D. D.: Quantifying Crop Responses to Brackish Water Use Across the Mediterranean with Minimal Input Modelling, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1272, https://doi.org/10.5194/egusphere-egu26-1272, 2026.
In Mediterranean regions, irrigation demand is rising while conventional water resources are becoming less reliable due to recurrent droughts, competing uses, and environmental constraints. Treated urban wastewater (TWW) is therefore gaining increasing attention as an unconventional resource capable of supplementing conventional irrigation supplies and supporting climate-change adaptation strategies. However, moving from isolated pilot schemes to implementation across large irrigation basins is complex. Reuse at this scale isn't a single pipeline linking one wastewater treatment plant (WWTP) to one field. Instead, it's part of a large, distributed, dynamic irrigation system serving many agricultural fields with varied crops and methods. Numerous, dispersed WWTPs produce TWW of varying quality, and the irrigation network conveys and mixes flows under different conditions.
The key planning challenge is therefore to integrate TWW with conventional sources within a single allocation and operations framework that considers both water quantity and quality. Quantitatively, planners must synchronise TWW and conventional supplies by matching seasonal availability to spatially variable irrigation demand across multiple districts, often under pronounced temporal mismatches that make storage and operational regulation essential. Qualitatively, TWW may contain pathogens and chemical contaminants, requiring preventive risk management throughout conveyance, distribution, and on-farm application. In the European Union, Regulation (EU) 2020/741 formalises these requirements by mandating a site-specific Risk Management Plan (RMP) and defining four reclaimed-water quality classes (A–D) linked to minimum quality standards and intended agricultural uses. Basin-scale planning must integrate volumetric allocation, infrastructure, and compliance considerations across diverse crop–irrigation setups with varying quality-class requirements. Current assessments often treat TWW as isolated; a unified framework combining these aspects is missing.
This study presents a novel, EU-aligned comprehensive methodology to assess and optimise the potential for agricultural reuse of treated wastewater in large, multi-district irrigation basins. The approach is designed to be generally applicable and adaptable to specific case studies, using routinely available stakeholder datasets integrated within a GIS-enabled framework. The methodology comprises six interconnected phases: (i) identification and spatial characterisation of areas suitable for reuse; (ii) area-specific resource–demand water balances (available resources versus irrigation requirements); (iii) assessment of current WWTP effluent quality according to Regulation (EU) 2020/741; (iv) determination of the reclaimed-water quality class required by currently irrigated surfaces based on crop type, irrigation method, and consumption mode; (v) definition of intervention scenarios to maximise reuse potential considering territorial and infrastructural constraints and irrigation needs; and (vi) identification of structural and operational measures prioritised over time to achieve sustainable, efficient, and EU-compliant outcomes.
The methodology was applied in Northern Italy within the Consorzio della Bonifica Renana (CBR) multi-district irrigation system, in collaboration with the local water utility (HERA). The application demonstrates how the framework transforms accessible information into decision-ready priorities, identifying candidate districts, WWTP clusters, and phased intervention portfolios and clarifies key barriers (infrastructure, storage, management, monitoring capacity, and quality-class constraints) while outlining actionable pathways to enable safe, Regulation (EU) 2020/741 compliant reuse at basin scale.
How to cite: Lavrnić, S., Maistrello, G., Drei, P., Mancuso, G., Valenti, F., and Toscano, A.: An integrated master plan to enhance agricultural water reuse at irrigation basin scale, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12108, https://doi.org/10.5194/egusphere-egu26-12108, 2026.
Since 2010, Chile’s central basins have faced an extended drought, stressing water systems. Particularly at Elqui River Basin, while direct reuse of treated wastewater is considered a management strategy to address water scarcity, regulatory and socio-economic barriers hinder its implementation. Still, a knowledge gap remains regarding the optimal allocation of such Non-Conventional Waters (NCW) and the systemic impact of reallocating the specifically 'freed-up' freshwater rights at the basin scale.
This study introduces a methodological framework coupling a hybrid Multicriteria Decision Making (MCDM) model with hydrological simulation. To address the complex interdependencies between conflicting decision factors, we apply a DANP (DEMATEL-based ANP) approach. Through a panel of experts, we build an Influential Network Relation Map (INRM) to derive global weights for technical, economic, and environmental criteria. This model prioritizes NCW allocation scenarios initially among competing sectors (e.g. mining, agriculture, urban, and ecosystems) and subsequently at the sectorial scale (e.g. irrigation canal sections).
The resulting prioritization schemes are input into a WEAP model of the basin. We simulate the hydrological trade-offs, evaluating how replacing freshwater with NCW impacts reservoir reliability and water demand satisfaction metrics. The study concludes by discussing the implications of these hybrid allocation schemes for integrated water resource management at the basin scale.
How to cite: Wiener, M. J. and Schulze-González, E.: Application of multicriteria hybrid model to address wastewater reuse strategies: the case of Elqui River basin in Chile, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15735, https://doi.org/10.5194/egusphere-egu26-15735, 2026.
This study presents an evaluation of an ecological sanitation initiative in the villages of Assaka and Akal Melloulne, in the Commune of Ouijjane, Province of Tiznit, Morocco. The project sought to enhance rural living conditions by implementing sustainable wastewater management systems based on constructed wetlands. Employing a participatory and gender-sensitive methodology, including field surveys, focus groups, and stakeholder interviews, the evaluation demonstrates significant improvements in environmental health and reductions in household sanitation burdens, particularly for women. The project also fostered strong social ownership. The reed bed treatment systems achieved high purification efficiency, and satisfaction rates were high, with 87% of Assaka and 90% of Akal Melloulne residents expressing positive views. Reported outcomes included improved hygiene, reduced odors, and enhanced quality of life. Strong community engagement and willingness to support future initiatives indicate robust local ownership. Additionally, the reuse of treated water for agriculture supports local economic activities. Despite these successes, further efforts are needed to increase women's participation in income-generating activities. Overall, the project offers a scalable model for rural ecological sanitation in arid regions, contributing to SDGs 5 and 6 (Gender Equality and Clean Water and Sanitation) and aligning with Morocco’s National Sustainable Development Strategy.
How to cite: Tadoumant, S., Ait El kadi, M., Aglagal, C., Gouahi, S., Rais, A., Bakas, K., Hssaisoune, M., Chaaou, A., Borzì, I., and Bouchaou, L.: Inclusive assessment of a pilot rural sanitation project from a human rights and gender perspective, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1581, https://doi.org/10.5194/egusphere-egu26-1581, 2026.
Across dryland regions worldwide, small non-strategic on-farm reservoirs serve as critical non-conventional water resources that enhance access to water for agriculture and households. This study examines the role of non-strategic reservoirs in drylands in advancing social, economic, environmental, and cultural sustainability in the context of climate change, by providing examples in four case studies in the Mediterranean region, Asia, Africa and Brazil. The results suggest that strategies aimed solely at maximizing farm income frequently expose farmers to extended periods of financial deficit, caused by variable rainfall and amplified by interest rates on borrowed capital. Such financial volatility is particularly problematic for subsistence-oriented, smallholder family farms that dominate these regions. Using a case study from Brazil, we demonstrate that improving financial resilience is possible by maintaining the same principles of water allocation while modestly lowering income targets. The study concludes that by incorporating hydrological uncertainty explicitly and its effects on the finances of local communities, non-strategic reservoirs can be managed more effectively to support livelihoods in dry environments.
How to cite: Iglesias, A., Souza Lira, C. C., Medeiros, P., Palacio, P., Duarte Arraes, F. D., Garrote, L., and Sivapalan, M.: Looking into the value of non-strategic reservoirs in drylands for social, economic, environmental and cultural sustainability under climate change, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7249, https://doi.org/10.5194/egusphere-egu26-7249, 2026.
Water management in dry regions is challenging due to high climatic variability, frequent droughts, and projected climate change, which cause water scarcity. In Ceará, Brazil, water security has historically relied on a dense network of reservoirs of varying sizes and playing distinct roles in the system, but management has focused on a few large reservoirs supplying strategic demands, while thousands of smaller reservoirs remain unmonitored and underused. These small reservoirs are particularly vulnerable to rapid water loss through evaporation, limiting their operation under conventional, risk-avoiding management strategies. Recent work has demonstrated that larger and hydrologically more efficient reservoirs are most appropriate to supply strategic human consumption that requires high reliability of water supply, whereas small reservoirs can be managed under more intense water withdrawal strategies for agricultural use. To support this water management approach, we propose a classification method based on hydrological efficiency, defined as a reservoir’s capacity to convert inflow into reliable withdrawal. The method uses the Triangular Regulation Diagram (TRD) to partition inflows into withdrawals, evaporation, and spillage, integrating reservoir characteristics (capacity, geometry, potential evaporation) and streamflow variability (coefficient of variation). Preliminary results indicate that, adopting a withdrawal threshold of 5% of the inflow, about 14,000 reservoirs (approximately 60% of the total network, which collectively represent only 3% of the total storage capacity of the system), can be allocated for agriculture without compromising human water supply. This study shows that non-conventional, efficiency-based management of small reservoirs can enhance resilience to water scarcity through a clear scientific grounded definition of reservoir classification and their respective roles, improving the use of the existing water infrastructure.
How to cite: Souza Lira, C. C., Augusto Medeiros, P. H., and Paton, E. N.: Reservoir classification based on hydrological efficiency to improve water governance in the drylands, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14695, https://doi.org/10.5194/egusphere-egu26-14695, 2026.
RainWater Harvesting Ponds (RWHPs) represent a critical adaptation measure for enhancing water availability for irrigation, reducing downstream surface runoff, and controlling soil erosion in Mediterranean mountain regions experiencing increasing hydro-climatic stress. The Shouf Biosphere Reserve (SBR) area in Lebanon presents an important case study for RWHP implementation, given the presence of hundreds of such infrastructures, built as both private and public initiative from the ‘60s and the climate vulnerability despite the high density of RWHPs in the SBR region, their historical placement was largely experience-based, or politically driven, lacking integrated hydrological, erosion, socio-economic assessment, resulting in widespread siltation and structural failure. Addressing this gap an integrated an evidence-based methodology is proposed that integrates hydrological and socio-economical factors to identify suitable RWHP sites in the area surrounding the SBR and offering a transferable methodology for comparable Mediterranean mountain contexts The study employed a multi-criteria approach integrating Geographic Information Systems (GIS), Multi-Criteria Decision-Making (MCDM), soil erosion modeling through the Revised Universal Soil Loss Equation (RUSLE), and participatory research. The results were obtained and the model calibrated through sensitivity analysis using 400 existing RWHPs mapped in the study area, which were categorized by public and private ownership. Biophysical and socio-economic criteria were integrated, including land use classification, soil data, rainfall patterns, digital elevation models, administrative boundaries, road networks, and water sources. Decision-makers and farmers' consultations provided crucial socio-economic insights and spatial context. The two final suitability maps, one for private and one for public ponds had a spatial distribution with the following statistical quartiles: Q1 = 6.15, Q2 (median) = 6.60, Q3 = 6.96 for private ponds and Q1 = 6.00, Q2 (median) = 6.50, Q3 = 7.00 for public ponds. Field-based site assessments conducted in five high-suitability areas ( >7.5) validated the model outputs, as several sites for RWHP were identified on field, demonstrating good performance of the methodology. The consultations revealed spatial variability in water sources and irrigation practices, confirming the relevance of pond infrastructure under increasing climate variability. However, the study identified the critical need for a cadastral map, currently unavailable in Lebanon, to enable a more realistic implementation process. This study represents the first applied research on RWHP suitability in the SBR area and the first to couple hydrological and socio-economical factors in the Lebanese context. The demonstrated methodology provides a valuable data-based decision support tool that can be scaled up at the national level for RWHP implementation, contributing to climate adaptation strategies in water-stressed Mediterranean regions.
How to cite: D'Alberton, N., Hassan, H., Forzini, E., Lucca, E., Castelli, G., Piemontese, L., Bresci, E., and Zolezzi, G.: Rainwater Harvesting Ponds Suitability maps coupling Hydrological and Socio-Economic criteria, a case study in the Shouf area, Lebanon, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-23136, https://doi.org/10.5194/egusphere-egu26-23136, 2026.
Small Agricultural Reservoirs (SmARs) are important agricultural drought adaptation measures. However, the monitoring and the management of SmARs is a challenging task in several areas of the Mediterranean, given the limited amount of information and support systems available for such relatively small structures. Recent national-scale mapping in Italy, developed within the CASTLE PRIN project – Creating Agricultural reSilience Through smaLl rEservoirs (https://sites.google.com/view/castleita/home-page), demonstrated the potential of satellite data to identify SmARs systematically. Following these efforts, within the Val D’Orcia Living Lab (https://agwamed.eu/italy-val-dorcia) of the University of Florence, we develop a co-production approach with local stakeholders to create a remote-sensing-based Decision Support System (DSS) for managing water resources in SmARs.
The Orcia watershed - a UNESCO World Heritage Site - is situated in Tuscany, Central Italy. It is morphologically characterized by a succession of hills composed of Pliocene clay, characterized by deep incisions of the courses of gullies and erosive formations typically associated with clay substrates. The soil is intensely cultivated in wide agricultural parcels characterized by simple arable land with sporadic tree crops (olive groves and vineyards) on the highest areas and near the major settlements, with a typical Mediterranean setting. The area is mainly characterized by rainfed agriculture but, in the last decades, farmers increasingly resorted to supplementary irrigation during summer.
The proposed approach takes advantage of a variety of remote sensing products to analyze the dynamics of emptying and filling SmAR in the area through the analysis of the reservoir area, using Stage-area-volume (SAV) curves derived from water-borne drone surveys in the case study and on-site monitoring of water levels. The scale of approach (farm- or watershed-scale) and the findings are validated in participatory meetings at the Living Lab to ensure the developed system meets local needs for water resources monitoring and drought management. The impacts and the possibility of detecting loss of storage volume due to sedimentation are also discussed. The resulting framework can enable the development of cost-effective and scalable tools, ensuring economic sustainability and practical applicability for farm-level and watershed-scale water management. The proposed approach can be out-scaled in other areas of the Mediterranean and further developed for similar water harvesting structures.
This research was partly carried out within the projects:
- AG-WaMED Project (CUP B53C22004860003), funded by the Partnership for Research and Innovation in the Mediterranean Area Programme (PRIMA), an Art.185 initiative supported and funded under Horizon 2020, the European Union's Framework Programme for Research and Innovation, Grant Agreement Number [Italy: 391 del 20/10/2022, Egypt: 45878, Tunisia: 0005874-004-18-2022-3, Greece: ΓΓP21-0474657, Spain: PCI2022-132929, Algeria: N° 04/PRIMA_section 2/2021]
- “Space It Up!” (call ASI n. 687/2022 of 26 July 2022, contract ASI N. 2024-5-E.0, master code: I53D24000060005, WP 7.6), funded by the Italian Space Agency (ASI) and the Italian Ministry of University and Research (MUR)
- CASTLE project, European Union Next-GenerationEU (National Recovery and Resilience Plan – NRRP, Mission 4, Component 2, Investment 1.1 – D.D. n. 104 02/02/2022 PRIN 2022 project code MUR 2022XSERL4 - CUP D53D23004920006
How to cite: Castelli, G., Lucca, E., Villani, L., Giambastiani, Y., Giusti, R., Mannucci, N., Sheikh Goodarzi, M., Lompi, M., Caporali, E., Chiarelli, D. D., Piemontese, L., and Bresci, E.: Co-production of a remote-sensing based approach for small agricultural reservoirs management in a Mediterranean watershed, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19477, https://doi.org/10.5194/egusphere-egu26-19477, 2026.
