Climate Robust Culvert Design

Full Title

Climate Robust Culvert Design: Probabilistic Estimates of Fish Passage Impediments

Project Overview

A culvert is a pipe or passageway that allows water to flow under a road or other obstruction. Many Washington State culverts are currently inadequate for fish passage. Blocked culverts keep salmon from swimming upstream to spawn.

For many Pacific Northwest rivers and streams, climate change is projected to result in higher peak flows. Recent work by the Washington Department of Fish and Wildlife (WDFW) has estimated the width that culverts need to be to accommodate anticipated changes in streamflow.

This project builds on the WDFW work by further investigating:

  1. The uncertainties in the approach to estimating daily weather and streamflow,
  2. The likelihood that a particular culvert size will fail as a result of climate change, and
  3. How these likelihoods and timeframes for failure may differ across the Skagit landscape.

We are also developing a prototype of an interactive tool that allows users to easily browse the results for specific locations within the Skagit watershed.


  • An online culvert-design tool that engineers, managers, regulators, and other interested parties can use to explore the impacts of climate change on fish passage.
  • Project report

Key Personnel

  • Guillaume Mauger, UW Climate Impacts Group (Project Contact)
  • Se-Yeun Lee, UW Climate Impacts Group
  • Jason Won, UW Climate Impacts Group
  • Anne-Marie Ou, Consulting Data Scientist
  • Daniel Larsson, Consulting Web Developer


This project has been funded, in part, by the United States Environmental Protection Agency under assistance agreement 00J991-01 to the Swinomish Indian Tribal Community. The contents of this website do not necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This work is supported through a contract agreement with the Skagit Climate Science Consortium.

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