Incorporating Climate Change into the Design of Water Crossing Structures


Wilhere, G., Atha, J., Quinn, T., Helbrecht, L., Tohver, I. 2016. Incorporating climate change into the design of water crossing structures. Washington Department of Fish and Wildlife, Habitat Program – Science Division.


The following report describes a study, conducted by the Washington Department of Fish and Wildlife (WDFW or the Department) from 2014 to 2016, to explore how climate-related changes to stream channel morphology could be incorporated into the design of water crossing structures such as culverts. The Department received a grant from the North Pacific Landscape Conservation Cooperative (NPLCC) that provided essential support for this work. This report fulfills a required deliverable of that grant.

Section 1 explains the importance of properly designed water crossing structures for fish movement, the basics of geomorphic culvert design, basics of channel hydraulic geometry, the projected impacts of future climate change on stream hydrology and channel morphology in Washington, and the motivations for this project. Section 2 describes our methods for translating climate projections to the key geomorphological parameter used in culvert design and permitting, and Section 3 presents the results and findings from our work. Section 4 explains how the information we have produced can be used for culvert design. Section 5 is a discussion of our results and the challenges of incorporating our projections into culvert design. Finally, Section 6 describes additional work needed to better address the information needs of policy makers, managers, and engineers.