On the Dynamics of Social Response to the 2011-17 California Drought

This study investigates the dynamics of social response during the 2011-17 California (CA) drought through a case study approach using climate and web search data. In this study, drought awareness (social response to drought) is defined as the relative search interest activities for the term “drought” in the state of California from January 2010 through October 2017 using Google Trends data. The 2011-17 CA drought was characterized in the Duration-Intensity curve with other historic CA drought for comparative purposes. The SPI12 and Google Trends data indicate there was a two-year gap between drought initiation (March 2012) and the first spike of drought awareness (January 2014). The first spike of drought awareness occurred when the drought condition reached its peak and the governor of CA declared drought emergency. In April 2015 when the governor issued water rules, drought awareness made another spike even though the actual drought condition had improved slightly since January 2014. Interestingly, California floods in early 2017 and Oroville dam failure stimulated drought awareness through debates over recovery two-three months in advance of the governor’s declaration on drought recovery in April 2017.

This study shows the value of a case study approach in socio-hydrological modeling, which informs us of the key determinants of social response to drought and is applicable to predictive modeling of the “observed” social response to drought. More realistic socio-hydrological modeling that integrates traditional and big data can eventually help us to develop strategies for stimulating timely drought awareness during the onset and recovery of drought when drought risk characterization is difficult (gradually increased or rapidly decreased).