Review of Research Conducted on the Sediment Delivery Ratio

Soil is a component of each ecosystem and it has more important role in human survival, therefore,
there is necessity for soil protection. Soil erosion and sediment are important environmental problems and
concerns in sustainable development. Although most erosion and sediment deposition processes have been
studied in detail, but modeling and making a link between on-site soil erosion and total sediment yield at
the outlet of a catchment are often hard because of the difficulties associated with modeling of a cascading
system, and also because of the lack of detailed input data at regional scales. Effective control of sediment
transport is important component in management of natural resource. Knowledge on delivery ratio is
useful in recognition of the resources and the amount of sediment load; also it’s more important for model
developers. Most regional erosion estimation models do not consider the spatial variability of sediment
supply to streams. Therefore, we should use an index such as sediment delivery ratio. Since, extensive
research has been conducted on the sediment delivery ratio, but different results have been shown. The aim
of this paper is to collect and review past studies on SDR since now, because we can choose the best way
to estimate sediment load and we can provide more effective actions for management of natural resources.
Results showed that each method has advantage and disadvantage, and it’s difficult to choose one way
for estimates delivery ratio. But most research in Iran showed that Renfro (1975) method is better than
others. Of course, all researches havn’t been conducted on all methods and this subject suggest necessity of
planning for the projects on sediment delivery ratio methods.