A cost benefit analysis of the Nimbus fish passage project

The aging, decrepit diversion weir at the Nimbus Hatchery places the American River's Chinook salmon and Steelhead trout at great risk. Due to the weir's state of disrepair, a storm or high river flows could destroy it at any time, causing thousands of fish to miss the entrance to the hatchery and depriving the river of a new generation of fish. The United States Bureau of Reclamation (USBR) recently proposed either replacing the weir or removing it and redesigning the ladder that leads fish to the hatchery. Methodology This paper presents the results of a cost benefit analysis to determine whether either proposed fish passage alternative would generate positive public benefit. My analysis uses benefits transfer to apply previously-determined values for fish. I analyzed the costs and benefits across several different scenarios, including a scenario in which recently-proposed salmon passage regulations would change the role of the hatchery. Conclusions Reached My analysis showed that the weir replacement or weir removal options could both lead to positive public value, depending upon the circumstances. Because the weir replacement carries higher up-front costs, that option is more tenable when one uses a low discount rate. Conversely, weir removal is the better option with a high discount rate. If the new regulations limit the usefulness of the hatchery, neither option is likely to result in a net benefit.