aboalhasan fathabadi; Ali Salajegheh; hamid pezeshk; Aliakbar Nazari Samani; hamed rouhani
Abstract
In order to manage and implement conservational activities in watershed successfully, it is necessary to determine the sediment sources. In recent years, sediment fingerpering techniques have been used for estimating sediment sources contribution. With respect to small source samples, having many answer ...
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In order to manage and implement conservational activities in watershed successfully, it is necessary to determine the sediment sources. In recent years, sediment fingerpering techniques have been used for estimating sediment sources contribution. With respect to small source samples, having many answer as a result of over fitting, there are some uncertainties in estimated sources contribution. In this study, the uncertainty associated with the multivariate mixing model was estimated using Monte Carlo simulation and GLUE approach in Zidasht-Fashandak sub- watershed. The sediment and source samples were taken in the study area and then, 54 geochemistry and three organic characteristics were measured. 17 elements were also selected as optimum tracer composition using Kruskal–Wallis H-test and multivariate discriminate analysis. Meanwhile, sources contribution were estimated using multivariate mixing models. Results showed higher contribution of sub-surface sources than the surface resources. Also, the distance between lower and upper limits for all sources and resolutely uncertainty bands were high.
kazem Nosrati; Saeedeh Jalali
Abstract
Identifying sediment sources is one of important factors in selecting of appropriate method of erosion control and soil conservation. The main objective of this study is to estimateuncertainty and contribution of forest roads to sediment yield in Ziarat Drainage Basin, Gorgan city using geochemical tracers. ...
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Identifying sediment sources is one of important factors in selecting of appropriate method of erosion control and soil conservation. The main objective of this study is to estimateuncertainty and contribution of forest roads to sediment yield in Ziarat Drainage Basin, Gorgan city using geochemical tracers. For this purpose, 47 soil samples were collected from different sources with different land uses and 14 suspended sediment samples collected from basin outlet. In order to identify sources of basin sediment yield and determine individual contribution of each source, 11 geochemical tracers including OC (Organic Carbon), Sr, Ni, Na, K, Cu, Fe, Mn, Ca, Mg, and Pb were measured in sediment and suspended-sediment samples. By comparing the tracers in the sediment sources and using statistical analyses of Kruskall-Wallis test and discriminant function analysis (DFA), three tracers of OC, Cu, and Fe were selected as optimum set of tracers in separating sediment sources. Eventually, using Bayesian model, land uses of agriculture, road construction and forest with 67.1(61.6-71.8), 31.4(27.1-35.9), and 1.2(0.1-5.1) percent, respectively were determined as the relative contribution from each source in sediment yield, and the highest uncertainty is related to the agricultural land use. The results of this study can be used to select the best appropriate method of erosion control in the study area and similar areas.
