Cracow University of Technology, Faculty of Environmental and Power Engineering, Warszawska 24, 31155 Cracow, Poland.
Cracow University of Technology, Faculty of Civil Engineering, Warszawska 24, 31155 Cracow, Poland.
Sci Total Environ. 2021 Dec 10;799:149469. doi: 10.1016/j.scitotenv.2021.149469. Epub 2021 Aug 5.
Grade control structures (GCSs) are one of the most often used hydraulic structures in a river regulation in mountain catchments. The purpose of their use is to reduce the river bed gradient and prevent downcutting. The aim of this study is to evaluate the influence of GCS on changes in river bed morphology. The study was conducted in a downstream stretch (5.66 km long) of the Carpathian river - the Mszanka, regulated with 25 GCSs. Research has shown that erosion is here a predominant process despite the use of GCSs. The river bed has been cut into bedrock along approximately 40% of a studied stretch. A total of 56 scour holes were identified, which vary substantially in terms of their depth, length, and mechanism of formation. The erosion depth depends mainly on the length of reaches between GCSs and on the water surface gradient. A surprising research discovery was scour holes found upstream of the crests of the GCSs - 16 such scour holes were found. The formation of these scour holes is explained through the drawdown profile characterized by the increasing of the velocity that favored the bed erosion. The studied river is characterized by deficit of sediment. The insufficient sediment supply and imbalance between the river's load and sediment transport are two of the greatest problems affecting the most Carpathian rivers. The novelty of this research is the analysis of such a long and complex reach of mountain river engineered with GCSs in terms of variances in erosion processes. Also a new knowledge presented here is an information about scour holes located upstream of GCSs and explanation of the mechanism of their formation. Results from this research could serve geomorphologists, engineers and ecologists as well as help river managers in decision-making processes when river regulation is planned.
梯级调控结构 (GCS) 是山区河流治理中最常用的水力结构之一。其使用目的是降低河床坡度，防止下切。本研究旨在评估 GCS 对河床形态变化的影响。研究在喀尔巴阡山脉的 Mszanka 下游河段（长 5.66 公里）进行，该河段有 25 个 GCS。研究表明，尽管使用了 GCS，但侵蚀在这里仍然是主要过程。河床在大约 40%的研究河段已经切入基岩。总共确定了 56 个冲刷坑，其深度、长度和形成机制差异很大。侵蚀深度主要取决于 GCS 之间的河段长度和水面坡度。一个令人惊讶的研究发现是在 GCS 波峰上游发现了冲刷坑——共发现了 16 个这样的冲刷坑。这些冲刷坑的形成是通过具有增加流速有利于河床侵蚀的下降轮廓来解释的。研究河流的特点是泥沙不足。泥沙供应不足以及河流的负荷与泥沙输送之间的不平衡是影响大多数喀尔巴阡河流的最大问题之一。这项研究的新颖之处在于分析了如此长而复杂的山区河流，这些河流都采用了 GCS，分析了侵蚀过程的差异。此外，这里还介绍了有关 GCS 上游冲刷坑的信息以及其形成机制的解释。这些研究结果可以为地貌学家、工程师和生态学家以及河流管理者在规划河流治理时的决策过程提供帮助。
