Conservation Leverage: Ecological-Design Culverts also Return Fiscal Benefits

Photo credit: Paul-Bakke-USFWS

Photo credit: Paul-Bakke-USFWS

By Eric O’Shaughnessy, Matthew Landi, Stephanie R. Januchowski- Hartley, and Matthew Diebel

Traditional hydraulically designed culverts impede ecological connectivity and degrade aquatic ecosystems. This problem is compounded by their ubiquity in the built environment. To overcome these limitations, alternative designs have been created to facilitate natural conditions and restore ecological connectivity. However, these “ecological design” culverts have perceived fiscal limitations that have prevented widespread implementation and consequently hampered conservation and remediation of stream ecosystems important for myriad fish species and aquatic organisms. We addressed these perceived fiscal limitations using cost–benefit analysis to estimate the lifetime fiscal net benefits of ecological design culverts over hydraulic culverts.

We found that in nearly half of all cases remediation with ecological design culverts was more cost effective than maintaining hydraulic culverts and that it is most cost effective on small streams compared to larger ones.

We also found that higher upfront replacement costs for ecological design culverts are overcome by their lifetime fiscal benefits. This is because of longer life span, reduced maintenance, and improved flood event resiliency of ecological design culverts. Our findings suggest that cost–benefit analysis could help conservation decision makers overcome higher construction costs and guide more cost-effective and sustainable solutions for aquatic conservation and ecological connectivity.

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