The presence of hydraulic structures within flow channels can result in changes to various flow parameters, including water levels. This study investigated the variations in water levels both upstream and downstream of a culvert by implementing different arrangements of artificial roughness within the culvert. Additionally, four distinct longitudinal slopes of the culvert were examined through a series of 148 experiments. The experiments were performed within a straight flume. Analysis of the results indicated that in all testing scenarios, the water surface level upstream of the culvert exceeded that downstream. Additionally, in every case, the average water levels both upstream and downstream of the culvert were higher in the regions adjacent to the right bank compared to those near the left bank. An additional significant finding was that the average water level rose in conjunction with increasing culvert slope. Furthermore, the highest water levels were observed in experiments incorporating artificial roughness characterized by maximum height and width—namely, 0.33 times the height of the culvert opening. This insight could be instrumental in predicting flow levels during culvert design and optimization. Lastly, an increase in the height of the incorporated artificial roughness corresponded to higher maximum flow levels.
Sadeghpour et al. (2025) studied this question.