Prioritizing Investment for Undersized Culverts

Ecosystems across the globe are constantly in a state of change; some from natural causes and some from human causes such as new developments or clearcuts that could impact runoff. Increasing rainfall intensity potentially puts road crossings at risk, including culverts, which may be undersized due to several causes, including climate change. The average lifespan of a culvert in British Columbia, Canada, is 57 years, a period long enough to include land use and climate change impacts on local infrastructure. The primary goal of this work is to determine the prioritization of culvert replacement and/or modification. Essential data include culvert specifications such as location and diameter along with environmental parameters such as precipitation, topography, and stream characteristics. Federal legislation, including the Fisheries Act, and provincial regulations, such as the Forest and Range Practices Act, impact culvert design and maintenance and must be considered. Environmental and social considerations for the proposed prioritization tool include considering if a culvert is placed in a fish-bearing stream and/or sensitive ecosystem, and the highway class and if it is an evacuation route during and after storms. A QGIS Python-based plugin to guide culvert prioritization was developed. The method and associated GIS tool developed can inform budgeting decisions by prioritizing the culverts most at risk, while providing simple culvert assessments with site-specific considerations based on the data available, fostering enhanced infrastructure resilience and ecological preservation in the face of climate and landscape change.