First, the design must ensure that the culvert pipe can withstand the impact of various levels of floods, ice floes, mudslides, debris, and other factors, remaining intact. Additionally, the scouring effects of floods on both upstream and downstream areas should be taken into account to ensure the stability of the embankment near the bridge or culvert.

Second, the conditions of existing or planned upstream and downstream bridges, culverts, and hydraulic structures, as well as their impact on riverbed evolution, must be considered.

Third, the design must be aligned with the topography of the riverbed. Excessive narrowing of the river channel or alteration of the natural state of water flow should be avoided.

Fourth, the size of the culvert steel pipe opening should be determined based on factors such as flood flow rate, riverbed geology, and the reinforcement methods for the riverbed and conical slopes. If conditions upstream of the culvert permit water accumulation, the flow rate calculated based on storm runoff may be reduced. However, the reduction should not exceed one-fourth of the total flow rate.