حفر الانجراف بالقطاع الشمالي لمجرى فرع رشيد

Abstract

The research investigates the phenomenon of scour holes in the channel bed resulting from water vortex movement. The study focuses on the northern sector of the Rashid Branch, extending from the Edfina bridges in the south to the mouth of the Rashid Branch in the north. It explores the origin and geographic distribution of scour holes in the study area, along with their morphometric characteristics, including length, width, area, depth, and shape.

The morphometric analysis and the analysis of factors influencing the formation and development of scour holes revealed their correlation with certain channel characteristics, such as channel width and water depth.

The study also addresses the factors influencing the formation and development of scour holes, including human activities in the channel (such as construction of embankments, dams, bridges, and stone revetments) and natural factors (such as water levels, flow velocity, and bed sediment volume).

Furthermore, the research examines the evolution of scour holes between 1981 and 2003 through the analysis of cross-sectional profiles of some scour holes in the study area. The morphological analyses indicate variations in the development of scour holes, with some showing accretion and others showing erosion, as revealed by sediment cross-sections. The study recommends periodic updates of hydrographic survey data for the study area to monitor the behavior and evolution of scour holes regularly.

Additionally, the study emphasizes the importance of considering scour holes when studying the geometric shape of artificial structures proposed for the channel, using mathematical models that incorporate all factors influencing the formation and development of scour holes.