Identify the effects of sand mining on grain size of river bed sediments (Case Study: Zarringol River in Golestan Province)

River acts as a system too, so that by human interference like sandmining from it's bed result in some changes. As you know human's development in structures trigger to enhancement in bed's sand and gravel. Unplanned sandmining has distractive effects on river bio environment morphology. The main purpose of this paper is identify the hydrogeomorphology changes resulting sand mining from Zarringol river bed. In order to perform this paper we have used some data and tools such as sediment samples, map, GPS, camera, shaker set and some software such as, google earth, Arc GIS, GRADISTATE, Excel. To identify the effects of sandmining on sediment grain size, samples taken from river bed sediments and were analyzed and the results were evaluated. The result shows great sand and gravel removal from the Zarringol river bed that conducive to severe changes in morphology and natural environment of the river. Also the results showed that the size of the river bed sediments samples upstream and downstream locations has changed dramatically from size of sandmining location samples. The mean diameter of the sediments samples upstream and downstream locations than the sandmining location samples has fallen However, the percentage of silt and clay particles and sand particles, a significant increase in sandmining locations which is natural because of the documented consequences arising from the sansmining, is suspension material and fine sediments. sandmining causes severe morphological changes such as deepening of the river channel particularly at sandmining locations, creating terraces on the sides of the bed and forming pits.