Opportunities for collaboration between infrastructure agencies and conservation groups: Road-stream crossings in Oklahoma

Abstract

Rivers and streams worldwide are highly fragmented by dams and road crossings, and there is a pressing need to retrofit the most problematic structures to ensure aquatic organism passage. At the same time, a majority of the transportation infrastructure within developed nations is beyond its projected lifespan and significant investments will be needed to ensure that this transportation infrastructure remains safe and functional. Historically, these two problems have been addressed separately. Here, we use a rapid survey methodology to identify road-stream crossings that are likely high-priority projects for both conservation and infrastructure agencies. We conducted a field assessment of more than 700 road-stream crossings across Oklahoma to determine if they blocked fish movements and to determine their physical condition. We then developed an index of ecological impact, and an index of infrastructure condition, based on physical variables measured at each crossing. This survey revealed a subset of crossings that are both fragmenting the river network and in poor physical condition. These crossings are high-priority locations where culvert replacement may have both high ecosystem benefit and would eliminate a piece of transportation infrastructure with a high risk of failure. We discuss opportunities for cost-sharing between conservation and transportation agencies.