Persistent Hydrological Consequences of Hurricane Maria in Puerto Rico

In September 2017, Hurricane Maria severely defoliated Puerto Rico's landscape, coinciding with a series of persistent hydrological consequences involving the atmospheric, terrestrial, and marine components of the water cycle. During the defoliated period, the atmosphere's thermodynamic structure more strongly explained daily cloud activity (R-PRE(2) = 0.02; R-POST(2) = 0.40) and precipitation (R-PRE(2) = 0.19; R-POST(2) = 0.33) than before landfall, indicating that post-Maria land-atmosphere interactions were comparatively muted, with similar precipitation patterns also found following Hurricanes Hugo (1989) and Georges (1998). Meanwhile, modeled post-Maria runoff exceeded statistical expectations given the magnitude of contemporaneous precipitation. Enhanced runoff also coincided with greater sediment loads in nearshore waters, increasing sediment content greater than twofold. This study offers a holistic narrative of hydrospheric disturbance and recovery, whereby the instantaneous, large-scale removal of vegetation is accompanied by hydrologic changes "upstream" in the atmosphere and "downstream" in rivers and estuaries. Plain Language Summary Although hurricanes pose well-communicated short-term wind and storm surge threats, this study documents persistent disruptions to the regional water cycle that can last for months following landfall. When Hurricane Maria struck Puerto Rico, its strong winds removed large amounts of leaf cover from the island's forests. In the months that followed, the absence of the typical vegetation cover coincided with a stronger relationship between a tropical weather forecasting parameter and subsequent cloud and precipitation activity. Simultaneously, a greater amount of sediment was washed through streams and rivers into coastal waters. The sediment content of nearshore ocean waters remained elevated for four months following Maria's landfall. Through the modification of land-surface vegetation, hurricanes are hypothesized trigger changes to the water cycle extending to both the atmosphere as well as the stream and river networks, ultimately deteriorating coastal water quality.