Structural network connectivity in a semi-arid catchment, Morocco

Abstract

In this thesis the concept of connectivity is combined with graph theory, where the catchment is seen as a network of nodes and edges. The benefit of this is that nodes can be hierarchized based on intrinsic properties and corresponding indices of the network. The Network Structural Connectivity (NSC) index is used to analyze the connectivity patterns in the Ounila catchment. Local hotspots are located with the NSC index and insights in the functioning of the catchment are addressed through flow analyses at the outlet of the catchment. Different scenarios are explored to assess the functionality of the proposed method: the effect of spatial extent on the method is investigated and the effect of restoration practices specifically in highly connected areas is quantified. The results from this research show that a connectivity-network approach is a good start to gain the first insights in the functioning of a catchment and to locate hotspots. However, the applied method would benefit from the inclusion of the distances of the sediment pathways. The addition of topological distance would not increase the complexity of the method excessively and is a promising next research step.