Considering Climate Change in Hydropower Relicensing: Suggested Remedies and Reforms to the Integrated Licensing Process

Abstract:

An increase in global atmospheric temperatures will have commensurate effects on regional hydroclimates, most notably in California's Sierra Nevada, where 40-60% of the state's surface water originates. The resulting hydrologic alterations will have several consequences for freshwater resources and ecosystems, including the disruption of timing and distribution of precipitation and runoff, which ultimately will alter the manner in which humans manage freshwater resources and ecosystems. Although climate warming and subsequent hydrological alteration are not yet considered by the Federal Energy Regulatory Commission (FERC) as part of in hydropower relicensing, it is foreseeable that future water delivery and hydropower operations will compensate for altered hydrology caused by a warming climate. Therefore, it is reasonable to assume that future FERC relicensing processes should begin take action to reduce and mitigate project impacts to downstream entities (e.g., water supply, recreation, and ecosystems) caused by altered or non-stationary hydroclimates. This study suggests remedies to FERC's Integrated Licensing Process (ILP) by specifying license conditions and/or operational agreements that incorporate criteria and triggers to reevaluate future hydrologic conditions, and it also recommends potential reforms to the ILP. To provide a roadmap for remedy and reform, an example methodology is provided that incorporates altered hydroclimates into operations modeling in order to explore downstream project effects. Altered flow regimes from the coupled changing hydroclimatology and compensatory hydropower operations, which seek to maintain generation and revenue, are then examined for ecosystem response through coupled reservoir and stream temperature models. This multi-model approach provides hydropower project operators with an example methodology to better understand the effects of climate change on system behavior, maximize hydropower generation with future conditions, and mitigate for negative impacts on ecosystems and other water users.