Sediment Fingerprinting Using the Approach of Reducing Uncertainty and Multi-stage Assessment of Tracers in the Idelo Watershed in Zanjan Province

In previous sediment fingerprinting studies, optimization of tracer signatures are not considered. Therefore, with different composite fingerprints, the amount of contribution from different sediment sources can be different from each other. Accordingly, the optimal composite fingerprint was determined using an approach of multi-stage refinement of tracers and reduction of uncertainties in the Idelo watershed in Zanjan province. In this approach, the ability and conservative behavior of tracers to separate sources are evaluated using variability ratios, conservatism test, range test, and finally, the conservative composite fingerprint as optimal composite fingerprint was determined. The detected composite fingerprint based on the introduced approach was different from a composite fingerprint obtained from conventional methods. Also, based on the aforesaid approach the related contribution of the geologic units in sediment yield were estimated 49, 32 and 19 percent for young alluvial deposits, red gypsiferous marl and old alluvial clastic, respectively. These results were different from those obtained using conventional and old fingerprinting methods with 11, 85 and 4 percent contribution in sediment yield for the aforementioned geologic units respectively. Generally, these results highlight the importance of applying the approach of multi-stage refinement of tracers and uncertainty reduction in determining the optimal composite fingerprinting of sediment.