Water-biota interplay

Water quality and land use

Water related fluxes and ecosystem services

Hazards data treatment and mapping

Hydrological modelling

Hydrometeorological variability and indices

Water resources resilience in basins and littoral environments

These two last sub-sessions provide new features on the analysis and treatment of climate variability, particularly precipitation, in basins close to here, such as the Senegal River basin, the Gambia River basin, and a little further afield in the Central African Republic.

They are interested in indicators of hydro-climatic evolution and resource resilience, such as the Intensity Duration Frequency (IDF) curves that evolve with Climate Change, or the occurrence of extreme rainfall, the soil water content analyzed by the wavelet method, or floods as in Benin or low flows in Algeria, monthly rainfall in Senegal,  or finally the saline intrusion in the West African plains. All these indicators are in themselves also indicators of resilience or vulnerability. In fact, these sessions also focus on the resilience of water resources, both in Côte d'Ivoire (through the Budyko method) and in Guinea (through the depletion coefficients). Presentations shed light on the impact of climate change on resources, in the Andes or in the Volta River Basin. We will also highlight in these sessions the difficulties of water supply and its facilities such as that of the Saloum Islands, the impact of variability on agriculture in Algeria. The impacts of human community activities, such as changes in land use, the multiplication of fish ponds or large hydraulic developments. Finally, many presentations are no longer as pessimistic as the common thinking long distilled by politicians, NGO leaders and sometimes even scientists.

The global water community FRIEND was established in 1985 to collect and share hydrologic observations for scientific assessments of flow regimes. These activities are still very relevant today and are reflected in IHP-IX, especially in Priority Area 3 "Bridging the Data-Knowledge Gaps". Today, there are many improvements in hydrologic observations, instruments and forecasts, and warning services. However, even today there are many gaps in this data-knowledge value chain that present significant barriers. In particular, international exchange of in situ observations is still limited and development of general, scale-relevant watershed theories based on available data is lagging.

The subtopic ST3 therefore intents to share experience on the following issues:

• Development of climate and hydrological services from local to global scales that improved the access to information on the status and future developments of water resources and quality.
• Open science and open educational resources in hydrology to exchange benefit and ways to implement open data and reproducible science in hydrology;
• Scientific data management and data exchange in hydrology, which are based on the maintenance, consolidation and expansion of existing hydrological networks / network data (like FRIEND-Water data bases, HELP basins, eco-hydrology demosites and/or similar) as stated in the IX phase of the UNESCO-IHP strategy.

Exploring hydroclimatic variability in large basins allows us to study the complex interactions between climate, hydrology, and water resources, providing valuable insights for sustainable management.

Sediment presence and transport in large basins play a crucial role in shaping river morphology, affecting water quality, and influencing sediment-related hazards like erosion and siltation.

Supporting shared water uses in large and transboundary basins demands effective governance and cooperation among riparian nations to ensure equitable access and minimize conflicts over water resources.

Understanding and predicting extreme events, such as floods and droughts, in large basins is vital for developing early warning systems and disaster preparedness to mitigate their potential impacts on communities and infrastructure.