Replenishment characteristics of riparian debris baits to rivers and the response to flow

Abstract

The riparian zone is a crucial interface between the aquatic and terrestrial components of river ecosystems. Organic matter deposited here can serve as an important food source for aquatic organisms, earning it the name of detritus bait. The construction of hydrological facilities has altered the flow rhythms of rivers, reducing the inundated area of banks and the frequency of flow velocity changes, which in turn negatively affects the ecological stability of the river. Given these reasons, it is crucial to understand the distribution characteristics of debris bait on riparian and the recharge pattern to rivers under flow impacts. The physical properties intrinsic to the debris in question were examined in order to ascertain their influence on the dynamics of debris transport through natural sampling methods. The distribution patterns of debris on natural river banks were investigated using density separation. A quantitative experimental model was designed based on the results of natural investigations to analyze the response characteristics of debris in-stream recharge to hydrodynamic structures at different flow velocities. The results indicate that the debris distribution is influenced by the background soil situation and flow effect. The soil layer immediately adjacent to the surface of the bank has a higher recharge effect. The main period for riparian debris recharge occurs at the onset of changes in flow rate. Furthermore, there is a positive correlation between the flow velocity and the quantity of debris entering the river. The findings of this study offer valuable insights into the replenishment of river bank debris bait under the current conditions, with implications for the ecological management of rivers undergoing hydropower development.