Complex response and geomorphologic thresholds in Large Dams

The intricate connection between geomorphologic systems and condition of a Large Dam, for example between alluvial channels, side slop elements, valley heads, Location of a Large Dam (for example Delijan Dam, In Iran) implies that discuss geomorphologic effects on a large Dam complexity. Such that any one part may suffer a complex of change through time while a new equilibrium is being achieved. This means that the behavior of such system is indeterminate. In so far as, it is not always possible to predict a unique, immediate pattern of outcomes resulting from a given stimulus for change in Dams. For example, when a small drainage basin of a Large Dam head is rejuvenated, the system responds not simply by incision, but by hunting for a new equilibrium by incision, aggradations and renewed incision. Such behaviors are an example of the complex response in the geomorphologic system that has complex effect on the Large Dam. Complexity of response is also compounded by the existence of thresholds. A threshold may be externally triggered if, for instance a drastic change in the climatic regime destroys vegetation and sets in train an intensity of erosion and increases Dams sediment and terrain modification quite distinct from that which preceded it and from which the terrain is incapable of recovery, even after a return to initial climatic conditions. An intrinsic threshold would operate if, for example, sediments stored within a fluvial system, (slopes, valley, slope step) became unstable at critical threshold slopes leading to accelerated erosion events, and therefore effect on the Large Dam, that discuss in this essay.