Putah Creek is an example of successful stream restoration
Putah Creek turning into a salmon stream

For years, Peter Moyle, a UC Davis pofessor and California fish expert, dreamed of the day when people could watch salmon spawning in Putah Creek from the Winters pedestrian bridge.
Last year, his dream came true when a determined pair of salmon set up housekeeping immediately upstream of the construction crossing for the new Winters car bridge. Easily observed from the west side of the pedestrian bridge, this pair surprised many by spawning despite the construction activity and constant human presence.
These salmon were just two of an estimated 200 fall-run Chinook salmon that migrated up Putah Creek in December 2014 to spawn. That was almost triple the highest number of fish ever recorded in any year over the previous 30 years, surprising everyone involved in the restoration of Putah Creek. In a typical year, observers find fewer than 10 salmon in the creek.
Read the complete article which gives further detail on the restoration efforts which brought about this result. Putah Creek turning into a salmon stream