Predicting the effects of river restoration

Photo Credit

Forest Service photo by Erika Reiter

Boulders placed in the South Platte River as part of restoration efforts following dam removal.

Managers, including the Forest Service, are spending millions of dollars installing wood structures in Front Range rivers in an effort to slow flow and trap sediment. It is not known how rivers will adjust their shape in response to the installation of these structures.

Researchers have built a computer model to predict how rivers change their shape after restoration interventions that are being used extensively in Front Range rivers, particularly in post-fire landscapes. The model shows that river channels tend to grow wider after restoration structures are built.

It also reveals that rivers become steeper or more gently sloping after restoration depending on the size of the restoration structures. Most importantly, the new model provides a way to predict river responses to restoration, which will allow more effective targeting of restoration interventions.

This new tool provides a way to predict these changes, potentially allowing analysis of the effects of restoration projects before they are installed and therefore enabling more efficient use of limited restoration funding. It has long been possible to predict how restoration interventions affect flow in rivers, but it has been difficult to predict how rivers will self-adjust their shape in response to restoration interventions. With this work, managers now have a way to make those predictions.