Investigation of land use changes around Glabar Dam in Ijroud-Zanjan city under the influence of dam construction

Land use change is one of the most important and fundamental manifestations of environmental change caused by human activities. Construction of dams is one of the most important and fundamental human drivers of land use change. The main purpose of this study was to investigate the impact of construction of the Golabar Dam on the use of upstream and downstream flood events in the Golabar catchment. In this regard, Landsat satellite images were used for two years ۲۰۱۱ and ۲۰۱۸, before the Glabar Dam was flooded and ۷ years after the dam was exploited. The ۲۰۱۱ satellite images were obtained from Landsat TM TM sensor and ۲۰۱۸ from Landsat ۸ OLI / TIRS satellite from Earth Explorer database. Pre-processing of images was performed in ENVI and ARC-GIS software. To detect land-use changes, MLH supervised classification algorithms were used, using a number of field sampling. After detecting land use changes during the two periods of ۲۰۱۱ and ۲۰۱۸, the T-Student test of confidence level of ۰.۹۵ was used. The results indicated that in total ۷ land use classes or main land cover were extractable in Golabar basin, including gardens, dryland, irrigated agricultural lands, residential towns and villages, poor rangelands, medium rangelands, and meadows. Blue. The results of the analysis of land use changes in the two periods before and after dam dam showed that changes occurred in all revealed land uses during the study period. Both land use and land cover of the poor rangelands and the average rangelands both experienced a decreasing trend during the period ۲۰۱۱ to ۲۰۱۸. While irrigated agricultural land use has increased and land use related to dryland agriculture has not changed significantly during the period under review. During the ۷-year period under review, the land use increased by ۲۵۸۳ hectares, accounting for about ۳% of the total area of dryland agricultural land in ۲۰۱۱. Garden areas have more than doubled over the period under review, with the ۲۰۱۸ area increasing by ۲.۷ times as compared to ۲۰۱۱. Residential areas comprising urban and rural areas in the study area have almost doubled over the seven-year statistical period from ۲۰۱۱ to ۲۰۱۸. So that the area of this land use increased over the ۷-year period of ۱۹۶۷۲ hectares. Statistical analysis using two-way parametric T-student test showed that there were not enough changes in the level of confidence to be considered significant. Therefore, during the last ۷ years, from ۲۰۱۱ to ۲۰۱۸, the reported user changes were generally not significant enough to be significant at the confidence level of ۰.۹۵.

کلیدواژه ها:

Land use ، Dam construction ، Gulabar basin ، supervised classification