Designing climate-change-resilient culverts and bridges

Most culverts are designed to last 50 to 100 years, exposing to changes in stream conditions related to climate change. Designing culverts to be resilient to future changes in stream conditions can reduce the risks of culvert failure and the creation of barriers to migrating fish.

How will climate change impact your project?

Scientists studying climate change have already noted changes in Pacific Northwest hydrology, including reductions in the size of glaciers, less snowpack, and earlier peak stream flow in many rivers. These trends are expected to continue, along with increasing flood size, and decreasing summer low flows. As the size of floods increases, so does stream width. The size of water-crossing structures like culverts and bridges is based largely on stream width.

The Washington Department of Fish and Wildlife developed a web application to help you understand how much the stream width at your project site may change in the future -- the 2040s and 2080s. With this information, you can make an informed decision about the design of your new culvert, bridge, or habitat restoration project. This decision may result in a wider culvert or bridge that can accommodate higher stream flows. Culverts and bridges built to accommodate higher stream flows are less likely to fail and block fish, which reduces future maintenance and repair costs.

Learn about your project site

Contact us to get future stream flow information for your project site

Jane Atha 

Learn more about the science behind our climate change web application in the project report Incorporating Climate Change into the Design of Water Crossing Structures.