Document Type : Research Paper
Authors
1 PhD Student, Faculty of Natural Resources, Tarbiat Modares University, Iran
2 Professor, Faculty of Natural Resources, Tarbiat Modares University, Iran
Abstract
Many on-site and off-site problems occurred due to irregular human use of natural resources leading to increasing sediment loads in watersheds. Understanding relative importance and source of erosion and sediment is essential for effective control of aforesaid problems. Today's, there are different techniques for determining sediment sources. However, the evaluation of their relative agreement has been less considered. Towards his attempt, the present study aimed to compare the results of fingerprinting, soil erosion feature map and direct field measurements of soil erosion. According to the results of fingerprinting technique, the red gysiferouse marl geological unit with 85 percent contribution in sediment yield was most important sediment source. It was in the same line with that reported from soil erosion feature map with code of CS23R41G42. The results of field measurements also showed that the red gysiferouse marl geological
unit with soil erosion rate of 34.4 t ha-1 and 14023 t annual erosion had the highest proportion in sediment yield. Other geologic units viz. young alluvial deposits and old alluvial clastic lied in second and third orders. These were also consistent with those of fingerprinting technique. Totally, the differences in the results of fingerprinting technique, soil erosion feature map and field measurement techniques referred to their quantitative or qualitative approaches and not considering sediment delivery ratio concept and other sediment transition processes. It clearly confirmed the necessity of simultaneous use of all aforesaid techniques to get access to reliable results.
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