Many streams have been blocked by obstructions to fish passage, such as dams and impassable culverts. In these cases, the goal of in-stream restoration projects is to remove the obstruction or construct an alternate fish passage around the barrier. Successful completion of this kind of in-stream work often allows salmon to return to kilometers of spawning grounds and other habitats that have been inaccessible for years due to human activities.

Creation of "Stream Complexing" features creation of marsh benches to help filter pollutants and provide shelter to fish and other aquatic species.

The placement of large boulders and rootwads also improves the complexity of in-stream habitats and provides shade and shelter for fish.

Livestock crossings reduce the impacts of horses and cattle on stream-banks and down-stream habitat. When livestock cross streams, their hooves trample the streamside vegetation, leading to habitat loss.

Campbell Valley Regional Park (2000)
The purpose of this project was to improve and increase coho salmon spawning habitat, stream complexity (pool development) and dissolved oxygen content. The proposed work involved the addition of rock weirs, boulder clusters, large organic debris (e.g. rootwads), and rock and log deflectors.