Factors affecting average grain size changes in rivers of a catchment area (Ardak catchment area, northeast Iran)

Investigation of sediment control factors in river channels a catchment can play very important role the sustainable management that catchment. For this purpose, Ardak was selected, on which reservoir dam constructed for drinking and agricultural purposes large city Mashhad northeastern Iran. Then 57 samples were collected from surface to depth 30 cm along four rivers: A (14), B (23), C (13), D (7). The subsequently weighed sieved particle-size distribution. Cumulative curves plotted followed by determination statistical parameters. Thirty-four representative fresh selected study using macroscopic features. Lithofacies identified field parametersand their mutual association following classification scheme Walker Cant Miall. Data textural parameters different rivers showed A, D, B, produce coarse sediments. In terms average grain size, has greater production gravel sediments sand mud According studies, effect formation (Mozduran 3, Tirgan, Mozduran 1) other (Chaman Bid, Sarcheshmeh, Shurijeh) include more shale layers is Examination sedimentary facies alluvial terraces shows effective producing gravelly sandy Finally, comparison size formed riverbeds area parameter past show tectonic activity as most factor controlling basin over time.