RECOGNIZING SEDIMENT YIELD BEHAVIOR IN GORGANROOD BASIN BY USING MASS CURVES

摘要

The key to effective sediment management, either in watershed or reservoir scale, lies in identifying and characterizing both the spatial and temporal nature of sediment delivery, this in turn will permit effective control measures to be performed, and sustainable development to be achieved. In this research 7 stations that are located ON upstream tributaries and along main river of Gorganrood basin were selected. 30 years mean suspended sediment loads of each stations were calculated. By producing mass curves, double mass curves, double monthly mass curves for all stations, it could be seen that in the upstream stations these curves show some pulses but in the downstream changes are smoother. According to climatic condition over most of the sub catchments and inter-annual variability of sediment yield we concluded that there is sediment storage and remobilization process in the main river system. So the increased or decreased sediment contribution from upstream tributaries are buffered by this process in downstream basin, this in turn would cause the sediment load at the outlet of the main basin to be less variable than the upstream tributaries.