An Assessment of Specific Sediment Yield of Geological Formations Using Investigated Sedimentary Deposits in Reservoirs and Fingerprinting

Sediment yield data, collected for most regions in Iran has been insufficient and not so reliable and there is still not any sufficiently reliable methodology available for sediment yield assessment in the country as a whole. On the other hand, an attainment of reliable sediment yield data is a must and key requirement for the design of effective sediment management as well as control strategies. Sediment deposition in reservoirs is assumed as a very useful tool in providing such data. The main objective of the present research was to discuss a combination of both source fingerprinting technique and reservoir sediment survey to provide reliable data on sediment yield of geological formations for three small catchments in Semnan Province, Iran. Throughout the study, the volume and mass of deposited sediments in reservoirs were initially assessed. Fingerprinting technique was employed to identify the contribution to, as well as the specific sediment deposition yield of each geological formation into reservoir sediments. Results indicate that there is a high spatial variation in Specific Sediment Yield (SSY) among the geological formations in all the three catchments varying from 2.98 t ha-1 year-1 to 0.16 t ha-1 year-1. The results also emphasize the importance of Quaternary Units and Upper Red Formation as the dominant surface sources within some vast areas of the catchments.