Oral Presentation International Conference on River Connectivity (Fish Passage 2018)

Avoiding fish passage impacts through basin-wide infrastructure project planning  (#147)

Alison Bowden

River basins that are, or will be, influenced by hydropower support a range of important environmental and social resources, including more than half of all freshwater fish species on earth and at least 6 million tons of fish harvested annually (Opperman et al. 2017).  Given the global influence of hydropower, fish passage through in-stream infrastructure is critical for access to seasonal habitats and for meta-population dynamics required to maintain riverine fish populations, and other species dependent on them.   Fish passage structures, at best, provide for successful movement of a subset of fish species, and generally do not allow 100% passage of any species.  Given the lack of understanding of the portion of species and of individuals of each species necessary to maintain fish populations and the ecosystem services they support, the adequacy of most fish passage structures, may be inadequate for sustainability.  While the focus on better fish passage design is necessary to improve passage for existing infrastructure projects, a far better approach is to avoid critical sites for new projects through planning at a basin-wide scale and identifying alternative sites that collectively avoid impacts to fish movement while achieving energy and water resource management goals.  We will present a framework called Hydropower by Design, which evaluates scenarios of potential future project sites and flow management and the expected impacts to environmental, social, and economic attributes, including those dependent on fish passage.  We will show examples to illustrate how energy and water resource management goals can be achieved while minimizing or avoiding impacts to fish.   While minimizing impacts does not ensure sustainability for fish species and populations, the potential outcomes can greatly exceed fish passage obtained through fish passage structures at individual project sites with high impact to fish movement, and certainly additive impacts among multiple project sites in critical areas.

  1. Opperman, J., J. Hartmann, J. Raepple, et al. 2017. The Power of Rivers: A Business Case. The Nature Conservancy: Washington, D.C.