Regional Assessment of Sediment Rating Curves in the different climates of Iran

One of the methods for estimating sediment is using sediment data of hydrometric stations, and establishment of a relation between flow discharge and sediment discharge as sediment rating curves. Because of the importance of these curves in sediment discharge estimation and lack of sufficient data and information for most of watersheds in Iran, this research attempts to study variation trend of regional sediment rating curves and the effective factors, for use the obtained results for the other watersheds. Then 29 hydrometric stations with suitable geographic distribution were selected and their sediment rating curves were determined. Those stations were zoning into four climates, and in every zone, a regression relation was established between percentage of sensitive area to erosion, percentage of vegetation cover, and area of the basins with slope of curves. This relations were significant in 95% level of confidence in humid climate, 99% level in semi humid and 90% level in arid climate, this results showed the effect of this variable on slope of curves, but this situation in the semi arid climate a significant relation did not occured.