Experimental study of the Location and type of pits extraction on the management of bed materials mining

Rivers are one of the most important borrow aggregates and sand and gravel mining in rivers due to the morphological, hydraulic and sediment transport characteristics and methods of extraction creates many negative effects in them. In this research, the influence of distance and shape of consequent bed material mining pits is investigated in order to infilling and rehabilitation and mining management with considering of incoming sediment via an experimental study. The results indicated that, by increasing of the distance between the pits, infilling of upstream pit is constant. But extraction along channel width can increase filled volume of upstream pit up to 10% and can increase migration velocity up to 42%. When the distance between the pits doubles, extraction along channel width can increase filled volume of downstream pit up to 28% compared to the extraction along channel length and reduction of migration velocity is up to 70% in extraction along length and width.