Co-creation is increasingly promoted within hydrological research as a way to address complex and contested water challenges, yet its meaning, scope, and implementation are necessarily  highly variable in practice due to the specifics of local contexts and goals. Within the framework of the IAHS HELPING (Hydrology Engaging Local People IN one Global world) decade and as part of the Co-Creation of Water Knowledge working group (CCWK), we conducted a systematic review of co-creation in water-related research to examine how collaborative knowledge production is conceptualized, operationalized, and evaluated across the hydrological research lifecycle. We focus explicitly on co-creation processes that involve empowering or co-leading of societal engagement, excluding one-way consultation or extractive participation.

Following a structured multi-stage screening of 3,971 publications retrieved from Web of Science and Scopus, we identified and analysed 144 case studies that met stringent co-creation criteria. The review was guided by a qualitative screening framework developed within the CCWK working group and structured around four core elements of co-creation—relationship building, leadership, tools and techniques, and knowledge inclusion—together with four overarching principles: inclusivity, openness, legitimacy, and actionability (Castelli et al., 2025).

We observed a rapid increase in co-creation approaches in hydrology after 2013, concentrated in Europe and North America. Rivers, urban water systems, and watershed management were the most frequent focus of co-creation. Most  processes were initiated by researchers, in contrast to community- or government-led initiatives. While collaborative and facilitative leadership was frequently reported, genuine redistribution of decision-making power was rare and/or poorly documented.

Recurring bundles of tools rather than single techniques were used for co-creation, most commonly workshops, interviews, participatory mapping, modelling, and scenario-based approaches. Scientific and governance knowledge overwhelmingly dominated, in contrast to Indigenous and traditional knowledge systems. Although most studies claim actionable outcomes, concrete evidence of implementation, long-term impact, or environmental change was uneven, and evaluation frameworks were scant.

Overall, our review shows that co-creation in water science is widely invoked but inconsistently defined, implemented, and assessed. We identify recurring structural barriers related to funding architectures, institutional constraints, power asymmetries, and short project timeframes. By synthesising empirical patterns across cases, this study clarifies where and how co-creation contributes meaningfully to addressing wicked water problems, and where its application risks becoming rhetorical rather than transformative. This review lays the work for our future work developing a vision for what co-creation of water knowledge should become in the next decade and how we can get there.

This work was performed as part of the IAHS HELPING Working Group on “Co-Creating Water Knowledge”: https://iahs.info/Initiatives/Scientific-Decades/helping-working-groups/co-creating-water-knowledge/ 

References: 

Castelli, G., Howard, B. C., Adyel, T. M., AghaKouchak, A., Agramont, A., Aksoy, H., … Ceperley, N. (2025). Co-creating water knowledge: a community perspective. Hydrological Sciences Journal, 70(16), 2899–2919. https://doi.org/10.1080/02626667.2025.2571065

How to cite: Merheb, M., Hall, C., Amanambu, A., Aslam, H., Hossain, S., Chun, K., Fradi, F., Choukrani, H., Ceperley, N., Cudennec, C., Castelli, G., Udayar PIllai, S., Panchanathan, A., Koren, G., Llsat, M. C., Howard, B., and Ouarani, M. and the CCWK WG Review paper team: What does co-creation of knowledge look like in water sciences?  , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12326, https://doi.org/10.5194/egusphere-egu26-12326, 2026.

In 2020, the FLOODUP Francolí project was carried out to gather information about the flash flood event that affected the Francolí River (Catalonia, NE Spain) in October 2019. The ultimate goal was to involve the local population in improving resilience to sudden and catastrophic floods, which are relatively frequent in the area. To achieve this, a citizen science experiment was developed in collaboration with various local stakeholders, along with co-creation workshops. One of the campaign’s results was the reconstruction of the social response during the emergency. Its analysis highlighted the need to improve flood preparedness and response, leading to the continuation of the study through a new participatory process developed through the Flood2Now project.

This project also incorporated citizen science, with two main objectives: a real-time river level monitoring through citizen participation and raising awareness of risk perception through the reconstruction of collective memory. The project was carried out in two areas: the Francolí river basin and the Arga river basin in Villaba, Pamplona (N Spain). As part of the participatory activities, participants were invited to share their knowledge of flooding by taking part in co-creation and historical reconstruction workshops adapted to the specific characteristics of each community. Workshops were also held to select river level monitoring points jointly. Once these locations had been defined and validated by the project team’s hydrologists, observation posts were installed to facilitate monitoring. This communication will describe how co-creation process and activities were adapted to the specific characteristics of each territory and community and present the main results obtained. It will also show the differences in the river-community-territory relationships of each pilot and identify the barriers and opportunities for achieving the planned objectives.

How to cite: Llasat-Botija, M., Varela, O., Marcos, R., and Llasat, M.-C.: Citizen science and co-creation of knowledge to improve resilience to floods , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-8060, https://doi.org/10.5194/egusphere-egu26-8060, 2026.

Sustainable water resource management increasingly relies on integrated modelling approaches that jointly address the evolution of hydrological processes, and the quantification of anthropogenic water uses. This contribution aims to illustrate the maturity of such an approach by combining hydrological modelling results with spatially explicit estimates of water withdrawals and consumption. The objective is to support territorial stakeholders by providing a coherent view of future water resource trajectories and associated allocation challenges.

The study is conducted over the Vienne River basin (~22,000 km²) through a partnership between three French actors with complementary expertise and an interest in the future of water resources:

• CEREMA, the French public agency leading expertises for adapting territories, has developed STRATEAU [1], which reconstructs monthly water-use volumes by sector (agriculture, industry, energy production and tertiary activities), and aims at contributing to the quantification of water withdrawals and consumption.
• EDF (leading electricity producer in Europe) contributes with the hydrological modelling at the basin scale, using its experience gained through its involvement in the French EXPLORE2 project [1] which addresses the impacts of climate change on hydrological regimes.
• Vienne EPTB (Vienne River Basin Public Authority) provides in-depth knowledge of the territory, supported by previous hydroclimatic studies conducted to inform regulatory approaches related to allocable water volumes.

The set-up of STRATEAU (definition and calibration of the underlying assumptions) relies on shared expert judgement among the partners, with a central role played by the EPTB in ensuring the consistency of scenarios with local hydrological and territorial realities. STRATEAU is then used to translate climate and societal evolution scenarios — consistent with national reference studies [2] — into projections of water withdrawals and consumption. These results are combined with hydrological projections derived from the EXPLORE2 framework, enabling an integrated analysis of the joint evolution of water availability and water uses.

The results highlight the benefits of the dialogue between scientific, industrial, and institutional stakeholders and the added value of combining heterogeneous modelling tools. Preliminary spatial analyses illustrated below (for the year 2020), show the distribution of available water volumes across the basin and the estimated total withdrawals for all sectors, while temporal analyses allow the exploration of the seasonal dynamics of ratio between resource availability and water use.

This work identifies several perspectives: the need for a more explicit representation of the sensitivity of hydrological simulations to water abstractions, depending on their origin (surface versus groundwater), and the desirable integration of water management measures, that influence availability of water at annual and basin scales.

Total estimated withdrawals (left) and average discharge (right) for 2020 summer period (jja) over the Vienne River watershed.

[1] Lecomte J., et al. STRATEAU – une approche novatrice et un outil innovant de gestion prospective des tensions sur l’eau, 2023, DOI : 10.54563/asgn.2359

[2] Tristan Jaouen et al. Will rivers become more intermittent in France? Learning from an extended set of hydrological projections. Hydrology and Earth System Sciences, 2025

How to cite: Lamouroux, R., Beaufort, A., Debein, C., Dolidon, H., Neel, C., and Piccioni, F.: Combining hydrological and water-use models for watershed management: informing stakeholders on resource projections and strategic allocation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17078, https://doi.org/10.5194/egusphere-egu26-17078, 2026.

For Māori, the indigenous people of New Zealand, waterways are not merely physical resources, they are living systems with their own mauri (life force). These waterways sustain livelihoods, support cultural practices, linking people to their ancestors and to place. Because of the importance of waterways, Māori have been monitoring them for centuries, using traditional practices while also incorporating new monitoring technologies over time. This project investigates the potential of satellite-based remote sensing to complement and strengthen indigenous led waterway monitoring in the Ruapehu region, New Zealand.

The Ruapehu district is within the tribal lands of the Iwi (tribe) Ngāti Rangi. The lakes, rivers and springs of this area connect the people to their ancestral mountain, Mount Ruapehu. Ngāti Rangi practices cultural stewardship by monitoring changes in these waterways. Their current monitoring relies primarily on in situ observations. Combining satellite based remote sensing data with Ngāti Rangi’s existing in situ monitoring systems offers an opportunity to enhance understanding of waterway condition and change at more frequent time intervals at multiple sites across the region.

This research adopts a co-creation approach where discussion with Ngāti Rangi has guided the selection of significant waterbodies and monitoring parameters. Multi-spectral imagery from Landsat 8-9 and the Sentinel-2 satellites is used to derive data that tracks changes in water colour and related indicators of waterway condition. These satellite-derived datasets are processed and anaylsed against Ngāti Rangi’s existing in situ observations to evaluate how satellite-derived datasets may support existing environmental monitoring strategies.

This case study contributes to emerging socio-hydrological practice by demonstrating how remote sensing technologies can support Indigenous-led waterway monitoring. It highlights both the opportunities and challenges of integrating remote sensing technologies within existing Māori environmental management systems and offers transferable insights for co-created monitoring in other Māori environmental contexts.

How to cite: Ronald, I., Procter, J., Whitehead, M., Whaanga, H., and Gabrielsen, H.: Assessing Satellite Remote Sensing for Indigenous Waterway Monitoring, A Co-Created Case Study from the Ruapehu Region, New Zealand, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-4563, https://doi.org/10.5194/egusphere-egu26-4563, 2026.

Implementing Nature-based Solutions (NbS) in Taiwan’s steep, rapid-flow river environments faces a unique governance paradox where high-level policies encourage ecological restoration yet frontline engineering practices remain constrained by strict flood safety liabilities. This governance challenge is particularly pronounced in the Gangkou River watershed, a biologically rich region adjacent to the Kenting National Park at the southern tip of Taiwan. Notably, the demonstration site for this study was not unilaterally selected by the research team but was identified by local stakeholders advocating for restoration. The conflict between local demands for water recreation and flood safety versus rigid concrete check dam designs necessitates scientific mediation.

To echo the social inclusivity emphasized by NbS and promote its practical implementation in Taiwan, the key challenge lies not in the lack of hydraulic modeling tools but in the absence of a mechanism to translate qualitative Stakeholder Narratives into adaptive engineering language to assist in assessing the multiple benefits of NbS in disaster prevention and ecology. Therefore, this study proposes a Socio-Hydrological Framework integrating Participatory Modeling (PM).

Drawing on the bi-directional translation and iterative spirit of the Story-And-Simulation (SAS) approach, we attempt to establish an intuitive process for mapping qualitative needs to adaptive schemes and utilize two-dimensional hydraulic simulation as the quantitative calculation method. First, through Upward Translation, key needs proactively raised by locals (including biological, security, and cultural demands) are directly mapped and translated into model parameter settings for NbS adaptive planning scenarios. Next, through simulation calculations, Downward Translation converts physical data into visualized trade-off indicators (such as Habitat Suitability and Flood Risk maps) which are fed back to stakeholders for Social Iteration.

Through this systematic translation process, the study aims to establish a bottom-up, iterative decision-making pathway that supports community consensus-building and provides a scientific reference for advancing Nature-based Solutions in ecologically sensitive and high-conflict river environments in Taiwan.

This framework was applied to the Ba-Yao Bridge reach to evaluate three scenarios: Baseline, Ecological-oriented (Full Removal), and Integrated NbS (70% Height Reduction with Regraded Banks). Preliminary simulation results indicate that the Integrated NbS Scenario demonstrates typical advantages of nature-based solutions, generating significant hydraulic synergy: lowering the existing check dam height by approximately 70% increased flow velocity while effectively reducing local water levels. This hydraulic margin, facilitated by feasibility discussions with right-bank landowners regarding regraded banks, allowed for the design of vegetated slopes that enhance longitudinal connectivity without causing flood risks for adjacent farmlands to exceed safety thresholds. Furthermore, the design reduced flow disconnection time by nearly 80% during low-flow periods, effectively addressing stakeholder concerns regarding eutrophication, shallow water depths, and the desire to restore childhood memories of water accessibility.

Ultimately, this study preliminarily validates that the conflict between flood safety and ecological restoration often stems from rigid engineering constraints. By systematically translating social values into NbS design parameters and aligning with local policies like 'Sediment-Water Inundation Zones' and regraded embankments, we establish a bottom-up iterative decision-making process to provide a solid scientific foundation for promoting Nature-based Solutions in high-conflict, ecologically sensitive areas.

How to cite: Hsu, J.-C. and Liao, K.-W.: A Socio-Hydrological Framework for Nature-Based Stream Restoration: Integrating Engineering Safety and Social Narratives in Taiwan, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9197, https://doi.org/10.5194/egusphere-egu26-9197, 2026.

Water-related and environmental challenges increasingly emerge from complex human–natural systems, where hydrological processes, ecosystem functioning and human decision-making are deeply interconnected through non-linear feedbacks and cross-scale dynamics. In such systems, scientific knowledge alone is often insufficient to fully capture system behaviour, as local practices, institutional arrangements and decision processes actively shape both pressures and responses. Strengthening hydrological and environmental research through the integration of stakeholder and decision-makers’ knowledge is therefore essential to enhance system understanding, decision relevance and the effectiveness of management strategies.

This contribution discusses the role of participatory modelling as a co-creation pathway for water and environmental resources management, drawing on multiple research experiences and applications developed across diverse eco-socio-hydrological contexts. Rather than focusing on isolated sectors (siloed approach), the proposed perspective embraces an integrated view of environmental systems, where water dynamics are analysed together with ecosystems, governance structures and human behaviour, allowing insights to be transferable across contexts.

System Dynamics (SD) modelling is proposed as a particularly suitable approach for representing and managing human–natural complexity. SD modelling enables the explicit representation of feedback mechanisms, delays and non-linear responses, and supports the exploration of alternative system trajectories through the simulation of management and policy intervention scenarios. Within participatory settings, SD modelling provides a shared analytical space in which scientific evidence and experiential stakeholder knowledge can be jointly organised and discussed.

The modelling process is articulated through a qualitative phase, in which participatory Causal Loop Diagrams support the collective construction of system understanding and its possible evolution, and a quantitative phase, where these representations are formalised into simulation models to explore system behaviour, trade-offs and unintended consequences over time. Stakeholder knowledge is integrated throughout both phases, contributing to problem framing, identification of relevant variables and feedbacks, equation development and interpretation of model outputs.

Beyond knowledge integration, co-creation is understood as a process that actively shapes system dynamics through actors’ behaviours, strategies and interactions. In complex human-natural systems, decisions made by farmers, utilities, policy-makers and other stakeholders are not external drivers, but endogenous components that influence feedback structures, system trajectories and long-term outcomes. By explicitly embedding decision-making processes, behavioural heterogeneity and adaptive responses within participatory models, co-creation allows these dynamics to be explored, discussed and negotiated. In this sense, participatory modelling becomes both an analytical and a transformative process: it supports collective learning about system behaviour, reveals potential policy resistance and unintended consequences, and creates the conditions for adaptive management strategies that are not only technically robust but also socially legitimate and implementable.

How to cite: Pagano, A., Coletta, V. R., Selicato, L., and Giordano, R.: Participatory modelling as a co-creation pathway for human-natural systems management, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22369, https://doi.org/10.5194/egusphere-egu26-22369, 2026.

Accurate estimation of runoff potential is essential for watershed planning, flood assessment, and sustainable land and water management. Although the Curve Number (CN) method is widely used for surface runoff estimation, most existing studies still depend on static LULC–soil matrices or empirical CN values that overlook spatial heterogeneity and hydrological variability at the watershed scale. This introduces a methodological gap in deriving dynamically representative CN estimates that capture actual catchment responses. In this study, the Soil and Water Assessment Tool (SWAT) was employed to generate spatially explicit CN values across a diverse set of Hydrologic Response Units (HRUs) by integrating land use/land cover, soil hydrological groups, and slope classes. The analysis was conducted for the Ong watershed, an important tributary of the Mahanadi River basin in eastern central India, covering an area of 4,650 km². The model-simulated CN values were subsequently utilized to delineate runoff-potential zones within the watershed. Calibration and validation of SWAT-simulated runoff against observed streamflow strengthened the reliability of surface runoff parameterization. The spatial assessment revealed distinct patterns of low, moderate, and high runoff potential, predominantly governed by variations in LULC and soil texture. Built-up and agricultural areas exhibited higher CN values, while forested and permeable zones consistently showed lower runoff potential. Overall, the results demonstrate that SWAT-based CN derivation overcomes the limitations of conventional CN assignment by producing hydrologically consistent and spatially distributed runoff-potential maps. This systematic and scalable framework can support improved conservation planning, watershed prioritization, and climate-stress resilience assessments.

Keywords: Hydrological modeling; Curve Number; Hydrological Responses Unit; Runoff potential; Watershed management

How to cite: Prashant, P., Mishra, S. K., and Lohani, A. K.: SWAT-Based Estimation of Curve Numbers for Runoff-Potential Zoning, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-1038, https://doi.org/10.5194/egusphere-egu26-1038, 2026.

The International Association of Hydrological Sciences (IAHS) Working Group on the ‘History of Hydrology’ (https://iahs.info/Initiatives/Working-Groups/History-of-Hydrology/) was established under the leadership of Keith Beven in December 2022. In 2025, Okke Batelaan succeeded Keith Beven as chair. Before the establishment, several scientific activities demonstrated broad interest in the history of hydrology, thereby underscoring the opportunity and need for this Working Group (Beven et al. 2025). In 2018-2019, well-attended EGU sessions on the ‘History of Hydrology’ were organised. In 2019, a special issue on the ‘History of Hydrology’ in the ‘Hydrology and Earth System Sciences’ resulted in 13 published papers.

The aims of the Working Group are:

1: To provide a central repository for information on the History of Hydrology with liaison, links and metadata on the existing initiatives and copies or links to important historical papers from multiple countries.

2: To encourage more international contributions from countries that are not currently well represented in the existing resources, including the identification of important historical papers from those countries.

3: To encourage the recording of the contributions of female hydrologists.

4: To encourage the recording of the histories of experimental catchments where important advances in understanding of hydrological processes have been made.

5: To encourage the recording of the histories of hydrological models and the people who worked with them.

6: To provide a mechanism for the recording of the history of projects representing good practice in sustainable hydrology for societies under change, building on the Case Studies in Panta Rhei.

Since its establishment, the Working Group has been active in further sessions on the History of Hydrology at the IAHS-IUGG General Assembly, Berlin, in 2023, at EGU in 2025-2026, while a special workshop ‘From the History of Hydrology to the Future of Education’ was organised at Eawag, Switzerland, in 2025. A new Special Collection on ‘History of Hydrology’ in the Hydrological Sciences Journal has been very successful with so far 22 papers. Since 2018, more than 20 ‘History of Hydrology Interviews’ have been recorded with hydrologists (https://www.youtube.com/@historyofhydrologyintervie846). In these interviews, hydrologists share their personal stories about their careers, inspirations, successes, failures, collaborations, friendships, influences, and thoughts about the future. These recordings are inspirational for all, especially students, early-career researchers, and senior researchers. The often personal and historical accounts of scientific directions and developments, which are rarely found in journal papers, are a valuable source of information for hydrological education. The ‘History of Hydrology Wiki’ (http://www.history-of-hydrology.net/mediawiki/index.php?title=Main_Page) is another high-value educational resource, as it provides biographies of hydrologists, histories of experimental and research catchments, histories of institutions, hydrological textbooks, and an annotated bibliography.

Alltogether, the Working Group on the ‘History of Hydrology’ provides a gold mine of information that can be infused into hydrological teaching and education and inspire the next generation of hydrologists.

Beven et al., 2025, On the value of a history of hydrology and the establishment of a History of Hydrology Working Group. Hydrological Sciences Journal 70(5):717-729. https://doi.org/10.1080/02626667.2025.2452357.

How to cite: Batelaan, O. and Beven, K.: The IAHS Working Group on the History of Hydrology and the future of education, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17327, https://doi.org/10.5194/egusphere-egu26-17327, 2026.