The Unexpected Way We Can Make Streams Better for Wildlife

Originally published January 12, 2022

Have you noticed that it’s a bit wetter this year? You’re not the only one. More precipitation makes many of our day- to- day activities a bit more difficult, but it’s hard on our streams and wildlife too. Let’s get into it.

Besides being a beautiful feature of the natural landscape, waterways are an essential part of ecosystems.

Streams provide water sources for animals to drink from, as well as aquatic habitat for fish and amphibians. When rivers and tributaries are healthy and happy, it allows the essential riparian zones bordering them to thrive.

Unfortunately, if you’ve ever walked along a riverbank or crossed a stream while hiking, you know that it’s rare to see waterways untouched by human interference. While it’s easy for an untrained eye to spot litter and illegal dumping, anthropogenic degradation extends beyond pollution.

In some places, especially along trails and popular viewing areas, shorelines will be altered to allow humans better and safer access for recreation. Removal of debris, logs, sticks, and other organic materials might make for easier human access, but taking them away or otherwise moving them can be detrimental to the future health of the ecosystem, including leaving waterways more prone to erosion. It’s natural for some debris to move on its own, but losing too many of these complex barriers ultimately causes the same problems. Even things that seem harmless, like the ever-so-popular rock stacking trend, can contribute to growing problems for the future of the landscape. Moving and removing both large and small objects and debris means damaging critical habitat for large and small organisms, as well as reducing the amount of resistance that slows down high velocity water flow–and that causes a lot of problems.

When talking about waterways, velocity is the speed at which the water is flowing. The more water there is, the faster the flow. Velocity naturally changes with the seasons, slowing down in the summer months when the water is lower and the vegetation abundant, and speeding up in the rainy days of late fall, winter, and again in spring with the snow melt and subsequently higher water levels.

While variation is natural, ideally there should be elements in place to help curb the severity of the changes. Extremely high velocities make it difficult for spawning fish to fight the current, as well as for aquatic species who need low-flow areas to nest.

We are still currently in a La Niña weather pattern, meaning we can expect more extreme seasonal changes than an average year. During La Niña, northern areas often experience colder temperatures and a wetter-than-average precipitation rate. Additionally, as climate change continues to alter our expectations of what the “average year” looks like, we can foresee these changes to grow even more dramatically. Warmer temperatures means more snow melt in the spring, making these periods of high-velocity last further into the summer.

So what does this all mean? Clearly the fish were getting along fine before us. What can be done to curb the consequences of increased velocity? A common solution used by restoration biologists is to put back what was once there.

As trees were evolving, the deep networks of root systems they made helped to stabilize stream banks and allowed for deeper and narrower channels for the water, and ultimately changed the ways rivers flow. As they grew old and started falling into the water, they created logjams, forcing water to flow around them and forming habitats for wildlife to thrive in.

To see these restoration projects in action, you needn’t look far. Paul Olmstead, Assistant District Fisheries Biologist with the Oregon Department of Fish and Wildlife, has worked on a number of these projects, including coho salmon restoration at Sunshine Creek, and more recently a project located at Seeley Creek–projects that Oregon Wildlife Foundation are partners on. Conceptually, placing these logs is sort of like a big game of Tetris. In practice, it improves stream complexity and makes a meaningful difference to the health of fish, wildlife, and the ecosystem as a whole.

The next time you’re out enjoying local waterways, we encourage you to take a moment to think about the ways the landscape shapes each creature's experience. Whether human, fish, bird, or otherwise, we all get to share in the benefits of healthy water systems. We invite you to join us in our continued support on projects that keep it that way.