Designing stream crossings for water, wildlife, and people

Explore how right-size culverts can protect wildlife, reduce flood risks, and create healthier, more resilient waterways! It can be easy to equate streams to pipes—a way to get water out of the way and away from our roads and buildings. However, healthy streams are much more complex than your average plumbing. Undersized culverts can cause many issues for both wildlife and people. They create artificial barriers that prevent fish and other aquatic organisms from moving upstream while preventing large woody material from moving downstream. Water also speeds up when constricted, causing erosion downstream, altering stream geomorphology, and creating less safe conditions during floods. As our climate becomes less predictable and the frequency of droughts and heavy storms increases, it's more important than ever to right-size culverts. Upgrading to structures like bottomless arched culverts and bridges gives streams the space they need to function properly. In the history of the world, streams and rivers have far more experience handling floods than people, so it's our job to get out of their way as best we can.