Evaluation of Soil Saver Walls on Aquatic Organism Passage Through Box Culverts

Reinforced concrete box culverts are designed to provide hydraulic conveyance at peak stream discharge in a cost-effective manner; however, these structures can promote headcutting. Many state departments of transportation construct soil saver walls or similar structures on the upstream of box culverts to prevent headcutting. These walls act as a drop inlet and may hinder free movement of aquatic organisms. The potential impact on aquatic organism passage has resulted in regulatory pressure to develop alternatives or modifications to the traditional soil saver wall design. This article contains the results of an analysis of the potential impact of box culverts with solid soil saver walls on aquatic organism passage. The results of a survey of thirty states and fifteen field sites on the current state-of-practice for box culverts, and flume tests using model box culverts with a solid soil saver wall and with modified design to promote aquatic passage are presented. Modifications to the soil saver wall design are recommended based on the results of the survey of states, field surveys, and flume testing.