Climate change and flooding in the Susquehanna River watershed: An exploratory analysis of county hazard mitigation plans

The impacts of climate change are accelerating across Pennsylvania, one of the most flood prone states in the U.S., increasing the importance of hazard mitigation for communities bearing the brunt of more frequent flood disasters. Pennsylvania communities are developing hazard mitigation plans (HMPs), a potentially powerful tool for communities seeking to improve community resilience and reduce hazard impacts. At the same time, how climate change information is being included in HMPs has been little studied. This paper qualitatively analyzes 40 FEMA-approved local HMPs from the Susquehanna River watershed in Pennsylvania to assess how these plans address climate change impacts on flood risk. We find that plans authored by external consulting firms included more detailed information about climate change impacts on flooding than plans written by local government officials. None of the local HMPs achieved the best practice standard of including 1) place-relevant climate change information, 2) specific locations with existing, chronic flooding issues, and 3) quantitative information regarding both past and future impacts of climate change on flooding for that county, though several consultant-authored plans came close, lacking only future quantitative information. While plans authored by consulting companies generally include more of these elements of climate change impacts on flooding than plans authored by counties, the plans still vary widely in how they incorporated the information. These findings support FEMA's recent decision to require that climate change impacts be incorporated into local-level HMPs, but plan authors will need clear guidance on how to do so to facilitate forward-looking mitigation actions.