Applied Data Analysis and Mapping in R: Where in Western NC Do Vulnerable Communities and Future Increases in Streamflow Meet?

North Carolina GIS Conference 2019
Winston-Salem, NC, USA


Global climate models predict an increase in the frequency and magnitude of storm events in the Southeastern United States over the next several decades. Urban development in this region is expected to double by 2060 and associated increases in impervious surfaces may exacerbate flooding. Communities unable to respond and adapt to future changes in water resources are likely to experience adverse social and economic impacts. Socioeconomic metrics such as the social vulnerability index (SoVI) can be used to predict the location of potentially vulnerable communities but do not incorporate changing biophysical factors such as climate and land use change that impact streamflow. Hydrologic models, such as the Soil and Water Assessment Tool (SWAT), can predict the impacts of future climate and land use on streamflow but do not include socioeconomic factors (e.g., age, transportation access) that may influence a community’s ability to respond and adapt to future streamflow changes. Therefore, there is a need to couple SoVI and SWAT results to identify especially vulnerable communities for climate change adaptation planning. To address this need, we use R to implement a risk matrix framework approach that couples census tract SoVI estimates with changes in SWAT predicted streamflow from 1992-2002 (baseline) and 2050-2070 (global climate model projections) for the Yadkin-Pee Dee (YPD) Watershed in North Carolina, USA. We compare the spatial distribution of subbasins based on (1) SoVI results alone, (2) SWAT results alone, and (3) SoVI and SWAT results combined. SoVI results predicted spatially heterogeneous distributions of social vulnerability throughout the YPD and SWAT results predicted future increases in the number and variability of 10-yr and extreme flow events in southern regions of the YPD. The coupled SoVI and SWAT approach combined biophysical and socioeconomic factors to identify YPD subbasins with vulnerable communities that are likely to experience increases in 10-yr and extreme flow events. This approach can be used as the first of several steps (i.e., community surveying/focus groups, stakeholder visioning, and action taking) associated with effective climate change adaptation planning.

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sheila m. saia, PhD
Postdoctoral Researcher