Sediments, both coarse and fine, are essential components of riverine, estuarine, and coastal ecosystems. Their natural transport is critical to maintaining ecological integrity, preventing erosion, supporting aquatic habitats, and achieving major European environmental directives such as the Water Framework Directive, Floods Directive, and the EU Biodiversity Strategy. However, human activities—land use change, agriculture, flow regulation, and damming—often disrupt natural sediment balances, creating deficits or surpluses that compromise ecosystem services and infrastructure.

SedTrail develops a comprehensive and integrated framework to assess sediment sources, transport, and accumulation from the watershed to the reservoir. The project couples watershed sediment models with reservoir hydrodynamic models, enabling the quantification of sediment loads traveling through the river system and determining how much ultimately accumulates in reservoirs.

Traditionally, studies of rivers, estuaries, and coastlines are conducted independently. SedTrail bridges this gap by focusing on the critical transition between watershed and reservoir dynamics, offering a methodology that can later be extended to river–coast continuum analyses.

The Sorraia River basin and the Maranhão reservoir serve as the project’s case study. As one of Portugal’s most important agricultural valleys, the region faces hydrological stress, sedimentation issues, water scarcity, and future pressures linked to climate change and new infrastructure such as the Pisão dam. SedTrail will perform field campaigns, sediment fingerprinting, numerical simulations, and scenario analysis to support planning and decision-making.

The project’s results will provide essential knowledge for water managers, policymakers, and local stakeholders, strengthening climate resilience and sustainable water management

SedTrail aims to enhance sediment assessment and management through:

• Developing an integrated framework combining watershed and reservoir models.

• Quantifying sediment loads from the basin to the reservoir.

• Assessing sediment accumulation within reservoirs.

• Linking watershed management practices with sediment delivery.

• Supporting planning and adaptive strategies under climate and land-use change scenarios.

• Providing science-based tools for water managers and policymakers.

• Laying the foundation for future watershed–estuary–coastal continuum studies.