Infiltration mechanism of the sandy riverbed in the arid inland region of China

Study region: Two sandy riverbeds of typical arid inland rivers in northwest China: one controlled by ecological water diversion and one affected by intermittent flood erosion and sedimentation. Study focus: The infiltration mechanism in the sandy riverbeds of arid inland rivers is undetermined. This study simulated the effects of water diversion time and groundwater depth on ecological diversion channels as well as the effects of flood water level and clay layer on the infiltration capacity of flood-eroded riverbeds. This study provides a scientific basis for rational ecological water-diversion strategies and flood disaster prevention. New hydrological insights for the region: This study found that the water diversion period is very important to the local groundwater and ecosystem for ecological water diversion channels based on the total runoff. When decreasing the diversion time, the infiltration amount of the channel increased from 0.13 to 0.27 x 10(4) m(3) km(-1) d(-1). Therefore, distributing a fixed amount of water downstream in a short period can not only reduce losses, but also increases the amount of infiltration. The infiltration capacity of this channel is relatively strong for flood erosion channels of arid inland rivers, and the ratio of infiltration to total flood per kilometer of the channel was between 0.38 % and 1.41 % at different flood levels. Therefore, it is possible to artificially change the flow direction or carry out river silt remediation to infiltrate more flooding underground, which can reduce the harm of downstream flooding.