Rationale

The natural link between mountains, plains and delta’s is erosion and movement of material (sediments) in and from sources (mountains), the transport and movement of sediments and solutes by river systems to the plains, and deposition and storage in the sink zones (delta’s and sedimentary basins) = Source to Sink system.

Specific zones of the source to sink path are intensively used and reshaped by humans. Most of world’s population lives in alluvial plains and coastal delta areas, and much of the energy and water resources are stored in sedimentary basins at continental shelves. River courses including river beds and drainage networks are intensively utilized for transport, development and construction of infrastructure and industrial plants, and increasingly for human settlements. As a consequence, river management and engineering have increased along with human induced disturbance of the natural system.

The vulnerability created by this situation has become clear in recent years. Hazards such as recurring major flooding of river systems, in alluvial plains and deltaic regions all over the world and also for example the Danube River Basin – Black Sea area, are the reason for a growing awareness that overly rigorous human impacts on natural systems are becoming an increasing threat involving lost of human life, severe damage and disruption to infrastructure and high cost, especially from the perspective of climate change. In many instances these hazardous flooding events also include sediment disasters caused by riverbed changes associated with downstream propagation of materials derived from mountainous rivers and alluvial fans. Changes in sediment budgets and distributions have direct consequences for the environment, in terms of the functioning of both aquatic and terrestrial ecosystem. The inter-related disasters that comprise geohazard are all driven by geological processes and share ground deformation as a common thread. The densely populated Danube River Basin is threatened by earthquakes, landslides and flooding, with all three affecting the sediment budget. In order to be able to prevent the occurrence of these hazards, mitigate the disasters and restore a more sustainable environment solutions need to be found in terms of natural recovery processes.

The prerequisite and basis for this is a full knowledge and understanding of all aspects of the complex dynamic source to sink path and the need to discriminate between natural and induced impacts. However, our scientific understanding of this complex system involving intertwined connections and feedbacks, operating at different temporal and spatial scales, is rather poor. The purpose of the project is to contribute to increased understanding of geohazards, enabling improved preparedness for disasters and better ways to manage them when they occur, such as information products for end users involved in risk assessments.

While many specific component parts have been studied in isolation in the past decennia, a fully integrated research effort is still lacking. This program aims at significantly advancing our predictive capabilities by focusing on the quantitative analyses of coupled active and drainage systems through step-wise 4D reconstructions of sediments mass transfer, integrating geophysics, geology, geomorphology, state of the art high resolution dating, and numerical and analogue modeling. The challenge and innovation of this program is to link the scales and rates of the active processes, to constrain the variability in spatial and temporal patterns and rates of sediment transfer, to identify and evaluate critical threshold conditions and to connect them to the dominant forcing parameters, and to detect and interpret the significance of connected and disconnected pathways.

The CRP initiative is focused on the Danube River Basin – Black Sea source to sink system, a world-class natural laboratory, uniquely suited for the high ambition of this CRP. There is ample opportunity for excellent field sites to study together with local experts and a wealth of surface and subsurface data made available from each of the participating countries; the regional spread of the consortium covers the complete chain of source, carrier and sink. The Source-Sink CRP brings together expertise and know-how from all (sub) disciplines, covering mantle-lithosphere-surface-climate dynamics, analytical, observational and monitoring techniques and analogue and numerical modeling needed for an integrative approach to be successful.