Aeolian Sand Erosion and Deposition Patterns in the Arid Region of the Xiliugou Tributary on the Upper Reaches of the Yellow River

Abstract

Surveys show that rivers worldwide transport an annual sediment load of 15 billion tons into the sea, with the Yellow River Basin alone contributing 1.6 billion tons of sand. Therefore, understanding the wind and sand dynamics in the Yellow River Basin is crucial to ensuring the safe development of similar basins across China and the world. This study investigated the midstream wind and sand area of the Xiliugou tributary, a part of the upper Yellow River. Sand transport flux at 0–50 cm height on various underlying surfaces of the basin was measured using a stepped sand collector combined with an anemometer. Then, the amounts of wind and sand entering the Yellow River were estimated using a function model based on the measured factors. The particle size composition of wind-eroded sand was further analyzed to better understand the principles of wind and sand erosion and accumulation in the basin. The results show that the sand transport flux per unit area varies significantly across different underlying surfaces. The vertical change in sand transport rate on the basin’s surface shows that the total sand transport rate is an exponential function of wind speed. Based on this relationship, the total annual average wind and sand entering the Yellow River basin via the Xiliugou tributary was estimated to be approximately 8.09 × 105 t. Controlled by the basin’s unique geography, sand source, and human activities, the particle size composition of wind-eroded sand distinctly differs between the east and west sides of the river channel, exhibiting a “wind-blown mud and water-washed sand” pattern. The Yellow River basin still faces significant ecological security hazards. Understanding the coupling relationship between desert-basin-sand and wind is the foundation for effectively controlling wind and sand flow into the Yellow River Basin.