Fariba Esfandiary Darabad, Masoud Rahimi, Khodadad Lotfy, Ebadi Elhameh,
Volume 20, Issue 57 (6-2020)
Abstract
So that the morphological and transverse changes of the Ghezelozan River have been evident in recent years and caused some problems. In this study, the detection of river side changes was carried out using satellite imagery of TM and OLI Landsat 5 and 8 in the period 1993 to 2013, during which an interval of 158 km from the Ghezelozan River, using the transect method evaluated. The channel duct was divided into 24 transects based on morphology and the process of change. The average migration rate of the Gezelozan River duct has been around 4.47 m / year over the past 20 years. The highest transhumance rate between 1993 and 2013, at 10.58 m / year, is related to transect 16, resulting in 52.51 hectares on the right bank of the river. Overall, the results show that during the period 1993 to 2013, close to 207.14 hectares was added to the right bank of the river and nearly 215.31 hectares from the right bank were decreased. Also, in this study, sinusoidal index was used to study the shape of the duct flat, based on which there are 15 sinusoidal transects.
Fariba Esfandiary Darabad, Morteza Gharachorlu,
Volume 23, Issue 69 (6-2023)
Abstract
This study was aimed at identification and determination the spatial variations of sediment yield in Qarasu watershed located in Ardebil province, NW Iran, considering the negative consequences of erosion and sediment yield. In this regard, the monthly time scale, as the basis of work, was used to prepare the sediment rating curves. Preparation of monthly sediment rating curves based on sample flow and corresponding sediment discharge data in 19 hydrometry stations at the watershed during 14 years (2002-2015). All of statistical analyses were done by SPSS statistical software. Also, presentation of spatial variations in sediment yield over the watershed were made possible through the capability of GIS. The results of regression relations between flow and sediment discharge showed a close and significant relationship on a monthly time scale. The regional generalization of these relations for the whole basin showed that the seasonal difference was evident and the highest and lowest coefficient of determination was allocated to May (R2 = 0.74) and August (R2 = 0.55), respectively. Also, the highest and lowest sediment transport was observed in spring and summer, respectively, indicating the type of rainfall-runoff regime dominated on Qarasu watershed. In terms of the annual sediment yield, Yamchi station with 3970 tons per year and Nanakaran station with 66 tons per year, have the highest and lowest sediment yield among 19 stations of Qarasu watershed, respectively. According to the high levels of sediment yield in the Balikhly and Khyav sub-watersheds, it was recommended that more attention be paid to protecting and strengthening the water and soil elements and reducing the driven forces of erosion and sediment production in these sub-watersheds.
