Tuesday Poster session- Starting projects

Design rainfall is typically estimated locally from long-term, high-resolution rain gauge observations using Intensity-Duration-Frequency (IDF) curves. However, the data required to capture short-duration extremes are not consistently available across Europe, and existing national datasets are often difficult or expensive to access. We address this gap by compiling a large transnational dataset of sub-hourly rainfall observations. The dataset enables comparative analyses of rainfall extremes across regions and countries and serves as training data for a spatial machine learning framework. Preliminary results confirm the suitability of the Generalised Extreme Value (GEV) distribution for modelling annual maximum series. Building on these insights, we develop a graph-based model to predict IDF curves across Europe using publicly available climatological and geographical data. The resulting framework will provide consistent, high-resolution design rainfall data to support climate-resilient water management and planning. 

The impact of urbanisation and impervious areas on high flow regimes of peri-urban rivers is relatively well known : more intense and frequent peak flows. However, the impact of urbanization in low-flows, especially baseflow, defined as the share of streamflow coming from delayed sources such as groundwater, is complex and less known. This uncertainty in the response of baseflow to urbanisation is partly due to a lack of knowledge around subsurface flow paths. The age of baseflow, also named transit times, is an indicator of underground pathways at the catchment scale that is commonly used in ‘natural’ hydrology. Yet, it could become a promising tool to better understand how water travels underground in peri-urban catchments. AQUASUBURB is a starting project (2026-2030) that aims to estimate transit time distributions of baseflow across a gradient of urbanization. To do so, rainfall, baseflow, tap water and groundwater will be sampled weekly for two years in four contrasted catchments monitored in the OTHU program (field observatory for stormwater management) to calculate empirical transit time distributions. A process-oriented, distributed hydrological model (J2000P) will be set up for the four catchments to reproduce underground baseflow generation processes. This abstract aims to present the context, methods and expected results of the AQUASUBURB project. 

The impact of urbanisation and impervious areas on high flow regimes of peri-urban rivers is relatively well known : more intense and frequent peak flows. However, the impact of urbanization in low-flows, especially baseflow, defined as the share of streamflow coming from delayed sources such as groundwater, is complex and less known. This uncertainty in the response of baseflow to urbanisation is partly due to a lack of knowledge around subsurface flow paths. The age of baseflow, also named transit times, is an indicator of underground pathways at the catchment scale that is commonly used in ‘natural’ hydrology. Yet, it could become a promising tool to better understand how water travels underground in peri-urban catchments. AQUASUBURB is a starting project (2026-2030) that aims to estimate transit time distributions of baseflow across a gradient of urbanization. To do so, rainfall, baseflow, tap water and groundwater will be sampled weekly for two years in four contrasted catchments monitored in the OTHU program (field observatory for stormwater management) to calculate empirical transit time distributions. A process-oriented, distributed hydrological model (J2000P) will be set up for the four catchments to reproduce underground baseflow generation processes. This abstract aims to present the context, methods and expected results of the AQUASUBURB project. 

SobriEau, winner of ADEME's France 2030 Innov'Eau call for projects, is a four-year action-research project (2025–2029). Its objective is to achieve a lasting reduction in water usage in 60 existing buildings and their grounds across three demonstration local authorities by exploring several areas :

• Sufficiency: questioning water usage and needs through audits and users support
• Efficiency: testing and implementing water-saving devices and processes
  
• Water circularity and substitution, where relevant, will be achieved by reusing certain volumes of water within the building and its grounds and by modifying the type and quality of water used for certain purposes
  
• Overall circularity will be achieved by combining water savings with the development of local agricultural nutrient recovery sectors, particularly through urine diversion
  
• Public policy: contributing to the adaptation of local public policy by suggesting changes to economic models for water and sanitation so that substantial water savings are viable for the necessary services and investments

Climate change and urbanization contribute to urban water issues that have an impact on long-term sustainability, climate resilience and pollution. The CURE-NbS project will explore Nature-based Solutions (NbS) related challenges with the purpose of designing a innovative water management approach that integrates surface drainage systems into existing urban planning and reuse strategies. Nine different NbS across five international urban living labs (ULL) will be assessed through a combined modelling and monitoring framework. Each will be evaluated based on hydraulic performance to assess the effectiveness of NbS in mitigating excessive urban discharge during storm events, improve water quality and support effective water management strategies. Project results will also provide insight into co-benefits, socio-economic consequences and spatial implications of NbS. Structured project activities, such as interactive ClimateCafé workshops, will support stakeholder participation initiatives and adapt solutions to the local context. In addition, an open-source digital mapping tool, ClimateScan will leverage technology to facilitate geospatial data collection relevant to global climate adaptation strategies. Project outcomes are expected to demonstrate measurable improvements in urban water management and provide practical guidance for accelerating change and integrating NbS into existing planning and infrastructure. 

Frequent droughts and floods in Sri Lanka in recent years have had a negative impact on water resources, due to the depletion of groundwater, water pollution and soil erosion. As a result, people living in affected areas are seeing their living conditions and livelihoods severely affected. The project was launched in the Kurunegala district, in the arid zone of Sri Lanka, with the aim of improving productivity and strengthening the resilience of agricultural systems and value chains, thereby alleviating food and income insecurity in communities by providing them with tools and capacities for the restoration of watershed ecosystem services. As a result, farmers have adopted regenerative zero-waste agricultural practices, agroforestry gardens, and rainwater conservation and management strategies. Farmers have transitioned from traditional Chena cultivation to forest farming with buffer zones. In addition, women farmers have been empowered through increased income levels and social recognition within the farming community. 

Plastic has provided many benefits to human society; however, the overreliance and overproduction of plastic have resulted in a large proportion of plastic waste entering the natural environment. Plastics persist in the environment before degrading into smaller pieces called microplastics (< 5 mm), pollutants that can easily spread through aquatic ecosystems due to their small size, low density, and durability. Wet detention ponds are commonly used stormwater best management practices (BMPs) in coastal regions to intercept runoff during flashy rain events to reduce soil erosion, minimize flooding, and prevent pollutants from entering local waterways. Although detention ponds are often used to help manage water quality, little work has been done to evaluate their potential to retain microplastics from being released to downstream waters. In this study, we measured the distribution, abundances, types, and sizes of microplastics in the sediments of nine wet detention ponds from across coastal South Carolina, USA. The goal of this study was to evaluate how microplastics are spatially distributed in pond sediments to understand their capacity to retain these pollutants and improve downstream water quality. With this information, we plan to develop management recommendations for stormwater practices to improve microplastic removal. In this presentation, preliminary findings of the spatial distributions and types of microplastics in coastal South Carolina wet detention pond sediments will be shared. 

Microplastics (MPs) are increasingly recognized as major pollutants in urban stormwater systems. Identifying sources within complex urban catchments is essential for effective mitigation. This study proposes an integrated approach using handheld Fourier Transform Infrared (FTIR) spectroscopy and Geographic Information Systems (GIS) to enable rapid, in-field polymer identification and spatial mapping of pollutant sources. Fieldwork will be conducted in spring 2026, for example urban catchments, including buildings, street furniture and litter, and traffic. The combined FTIR-GIS methodology aims to support source control strategies and improve understanding of plastic pollution origin in urban environments. 

Microplastics (MPs), plastic particles smaller than 5 mm, raise increasing environmental concerns, and the concentration of human activities make urban environments a major source of microplastic pollution. The MPs generated in urban areas can contaminate the natural environment through a variety of pathways (atmospheric deposition, wastewater or stormwater discharge, …). The present study investigates the relative contribution of different pathways to the MP flux in the Seine River as it flows through the Paris megacity, as well as the temporal characteristics of MP transport and discharge. To achieve this, samples are collected in three different environmental compartments: (i) in the influents and effluents of wastewater treatment plants during dry and wet weather (ii) in untreated stormwater runoff in areas drained by a separate sewer system (iii) in combined sewers overflows during rain events. Samples will be prepared with H2O2 treatment and NaI density separation of MPs, then analyzed with µFTIR spectroscopy to identify MPs within the size range (25 – 5000 µm). The sampling campaigns have not yet taken place, but previous case studies in the Paris megacity can give first estimates. 

The NATALIE project, funded by the European Union, promotes the adoption of Nature-based Solutions (NBS) to enhance climate resilience across Europe. It includes eight case studies designed to demonstrate NBS effectiveness in real-world contexts. The Gran Canaria case study focuses on urban drainage challenges, particularly diffuse pollution from stormwater runoff and combined sewer system overflows affecting the Maspalomas Dunes Special Nature Reserve. An initial monitoring phase used sensors at key points in the drainage network to characterize water quality and pollutant transport. Using these data, a dual 1D/2D drainage model is being developed to simulate hydrological and hydrodynamic processes and water quality evolution in both the sewer system and surface runoff. The proposed mitigation includes a draining swale and a non-infiltrating bioretention system to intercept, filter, and treat stormwater before it reaches the wetland. Future project phases will assess the effectiveness of these measures under climate change scenarios and evaluate social, environmental, and economic co-benefits. All activities are implemented through a collaborative process involving local stakeholders and management entities, ensuring an integrated, participatory approach aligned with the conservation objectives of the protected area. 

Decentralised stormwater treatment and retention systems are becoming increasingly important for urban stormwater management. Rising efficiency demands and growing numbers of operational sites heighten maintenance needs, especially for decentralised filters requiring regular monitoring. Over time, pollutant loads can reduce filter permeability, leading to clogging of the filter, thus increasing the risk of flooding events and the entry of untreated stormwater into aquatic environments. Continuous monitoring helps to minimise such risks and ensures reliable operation and water protection. Research initiatives like the ReMoSys project demonstrate how digitalisation and sensor-based monitoring can enhance resilience, reduce operational costs, and support the sustainable management of urban water infrastructure.