Concept and Role of Structural and Functional Sediment Connectivity in Sediment Management of Watersheds

Soil erosion is a serious problem in the most regions of the world, especially a developing countries such as Iran that induce offsite and insite problems. Accordingly, the holistic understanding of the provenance, sediment source and sink areas, transport and fate of produced sediments is a very essential tool to achieve comprehensive management of watersheds. Sediment connectivity isone of concepts which is important to achieve aforesaid goals. Sediment connectivity is defined as the integrated transfer of sediment across all possible sources to all potential sinks in a system over the continuum of detachment, transport and deposition, which is controlled by how the sediment moves between all geomorphic zones. Assessing characteristics of spacial patternes of connectivity in a watershed allows to determine and identify degradation areas as source and effective catchment areas in sediment yield, sediment aggregation areasand sediment transfer pathways. So, mentioned approach and identifying sectors with similar sediment connectivity patterns support applying similar and integrated sediment control mitigation strategies. On the other hand, location and spatial configuration of landscape with different managerial scenarios are one of the most important factors which significantlyaffects sediment connectivity of watershed components and finally leads to decrease or increase sediment yield. Totally,a watershed hasdifferent erosions, sediment transfer and sediment yield responses to a unique and similar human disturbance but only with different locations and spatial configurations of landscape. Accordingly, to present comprehensive watershed management programs, investigation of structural and functional sediment connectivityunder sediment management programs, practicable scenarios and with respect to sediment degradation, transfer and aggradation patterns is indispensable.