Analyzing the Effects of Gravel and Sand Mining on the Morphology of Grango River (Between Sahand Dam to Khorasanak Village)

Stream gravel mining involves the mechanical removal of gravel and sand directly from the active channel of rivers and streams. Stream gravel mining, generally, causes incision of the channel bed, which can propagate upstream and downstream for kilometers as a result of which bridges and other structures may be undermined, and other environmental problems caused. The aim of this study is to investigate the damaging effects of excessive removal of sand and gravel from the Grango river bed. The materials of this research include topographic maps, geological maps, hydrological data, data provided from Dem and field data and Landsat Satellite image sensors of ETM 2008, and sensors of OLI 2013. To accomplish the aims set by the research, the river flows were calculated and the amount of permitted mining was estimated. The next step was to investigate the destruction caused by the river; sinuosity coefficient was calculated for the period between 2008 and 2013, and the amount of displacement in the river was estimated. Results showed that the river mining was much higher than the permissible limit and the sinuosity coefficient for the river in 2013 had had a significant increased compared to 2008. The results showed that the displacement of the moving rivers, and streams during the study varied between 75 and 100.