Coastal Freshwater Fate Following Hurricane Harvey

Abstract

Hurricane Harvey made landfall on 25 August 2017 on the Texas coast and produced nearly 162 km ³ of freshwater from precipitation on land and sea from 25 August to 1 September. Hydrographic data collected on the Texas continental shelf before and after the passage of Hurricane Harvey (2017) show that by 21 September 2017 (23 days following the storm) nearly 67 km ³ of freshwater had altered the coastal ocean hydrography and produced a freshwater coastal plume that stretched more than 200 miles (300 km) from Galveston Bay to South Padre Island, TX. The freshwater volume estimate accounts for roughly 92% of the volume expected to be on the shelf after adjusting for evaporation to the atmosphere and accounting for freshwater that remained on shore in terrestrial containment structures. Terrestrial river gauges account for 20 km ³ of the roughly 52 km ³ of freshwater water that entered the Gulf of Mexico from land, indicating that the majority (∼60%) of freshwater entered through non‐gauged locations that include over roads, low‐lying land and shallow estuaries. Our findings have challenging implications for prediction modeling of storm impact, surge dynamics, and coastal resource management, which largely rely on gauged station data to monitor discharge, surge, and sea level.