The complex INTERLink of safeguarding wAter availabilitY and quality to mitigatE and adapt to hydroclimatic extRemes – INTERLAYER project

The EU-Water4All project INTERLAYER, 2024-2027, aims to develop cumulative adaptation strategies in the complex interlink between surface and groundwater management, using water retention measures to reduce water runoff and fill-up groundwater storages, thereby minimizing hydroclimatic extreme events’ impacts in water quantity and quality. Water retention is explored through Slow Hydrology measures, guided by terrain and water balance analysis, and related to land use (especially agriculture), water quality and biodiversity from a synergistic perspective to facilitate robust future River Basin Management Plans. Future climate simulations are produced locally in order to ensure that the proposed measures improve the resilient, adaptation and mitigation to hydroclimatic extreme events.

The concept of Slow Hydrology is tested in four living lab watersheds. The key questions are: (i) how can excess water be stored to reduce water velocity during flash floods, using field topography and drainage systems to increase detention and infiltration strategically in the catchment; (ii) how can water availability during dry periods be improved, considering the water needs for human activities without compromising biodiversity conservation, water quality or ecosystem services; (iii) how can the suggested nature-based solutions influence the local biodiversity and provide benefits and co-benefits to local population and stakeholders. The living labs represent contrasting European edaphoclimatic regions with different geologic characteristics and land uses:

Portugal, Guadiana River - This living lab covering 136 km² in the Toutalga sub-basin is dominated by intermittent rivers and ephemeral streams (IRES), characterized by flash flood and dry-phase periods. The basin has a hot summer Mediterranean climate.

Denmark, Vaerebro River - The catchment of the Vaerebro river is 153 km² and the river itself is 35 km long, having its source in a biodiversity-rich bog area. This living lab has a mixed land use with small and medium-sized villages, many spare-time farmers, and some agriculture, before discharging to Roskilde Fjord. It allows for a source-to-sea approach in a,region with a continental humid and warm summer climate.

Austria, Liesing River - The Liesing river with a catchment of 112 km², the Liesing is often affected by strongly fluctuating water flows. During dry periods, the Liesing carries very little water. However, during heavy or prolonged rainfall, the Liesing can quickly turn into a river with high water levels.  The catchment can be divided in a forest-dominated area followed by an urban river section.  in a region with a continental humid and warm summer climate. 

Romania, Danube River - Spanning 77 km² along the Danube River floodplain between Salcia and Maglavit, this site features agricultural lands, wetlands, and peri-urban areas, with an elevation under 100 meters. It experiences a continental humid climate with hot summers. Protected under the Natura 2000 site, it also lies near other important conservation zones. The key challenges include drainage, water abstraction, urban development, deforestation, and rising temperatures, disrupting the hydrological balance and increasing drought risk.