Investigation of Characterized Sediments in the Field of Floodwater Spreading and Artificial Recharge (Case Study: Jajarm Aquifer)

Study of sedimentation trend in artificial recharge projects and flood spreading on the aquifer (Aquifer management) can be effective in designing structures and network management. Literature review shows that most studies in the flood spreading area shave been conducted in networks that have a low life span or low flood numbers. Since 1997, the flood spreading station on the Jajarm aquifer in North Khorasan province has recorded 37 floods. Events In this study, in order to investigate the surface sedimentation and soil texture changes in the flood spreading area, sampling of sediments were done in the main canal and 9 secondary canals. In the next step, three soil profiles inside the grid and a profile outside the field were drilled (as a control sample) and samples were taken at three depths of 0-30, 60-30 and 60-90cm. Sediment and soil samples were prepared by using standard sieves. The fine particles were gained by hydrometric testing. The results show that the sediments in the flood spreading network have silt and texture clay. The sediment aggregates become smaller toward downstream flood spreading region. Although the changes in tapes 4 to 9 are much less. The results of soil profiles show that fine-grained sediments are deposited on the surface of the soil at a depth of 0 to 30cm and a small portion of the sediments penetrates into the underlying layers. Based on the results, it is suggested in the implementation plans, the initial strips should be considered as sediment traps and the dimensions and distances of the structures should be designed in accordance with these conditions.