Bridge Impact on Water Behavior: Simulation-Application to the Medjerda River in Tunisia

The Medjerda Basin is a crucial hub in Tunisia, grapples with recurring floods, significantly affecting social and economic activities in the region. Flood-induced damages disrupt daily life, jeopardizing homes, agriculture, and businesses. This study delves into the intricate dynamics of hydraulic engineering within the challenging context of the Medjerda River Basin, responding to the global flood crisis. This study investigates channel response under diverse flow scenarios. It employs a novel approach by integrating real-scale and scaled-down numerical models to examine the impact of bridge structures on water behavior, providing valuable insights for watercourse management strategies. Simulations reveal distinct behaviors in varying velocities and surface water heights. For real-size models, an inlet velocity of 1 m/s and a water depth of 3 m are considered. In small-size models, conditions involve an inlet velocity of 0.1 m/s and a water depth of 13 cm. The use of both real-scale and scaled-down models, guided by the Froude similarity principle, offers a comprehensive analysis of water dynamics around bridge structures. The investigation seeks to uncover apprehension into the wall shear changes, velocity fields, and hydraulic properties under these conditions. The primary focus is on understanding the water behavior in the channel under varying velocities and surface water heights and assessing the impact of existing bridge structures on water properties. The study will compare numerical calculations to real-world observations in a geometrically reduced model, refining the numerical resolution through practical experimentations. Results from the simulations provide an understanding of water behavior in the Medjerda River, offering valuable insights into the variability of velocity fields. This research contributes to essential knowledge for developing a multidisciplinary approach that bridges hydraulic engineering, environmental conservation, and urban planning, in the face of changing conditions.