Award: OCE-1760006

Hurricane Harvey made landfall Friday, 25 August 2017, at 22:00 Central Time about 30 miles northeast of Corpus Christi, Texas as a Category 4 hurricane with winds up to 130 mph. This was the strongest hurricane to hit the middle Texas coast since Carla in 1961. After the wind storm and storm surge, coastal flooding occurred due to the storm lingering over Texas for four more days, dumping as much as 50" of rain near Houston. This produced one of the largest floods ever to hit the Texas coast, and it is estimated that the flood will be a 1:1000 year event. Increased inflows to the estuaries caused increased loads of inorganic and organic matter, which in turn enhanced respiration of coastal "blue carbon" and dissolved oxygen dropped to near zero for 5 days. The large input of riverine carbon and storm disturbance caused extensive estuarine "exhalation" in the Guadalupe Estuary (i.e., San Antonio Bay), with the one-month period following Harvey accounting for 35% of annual estuarine carbon dioxide release. In addition, the flood also caused a large change in salinity. The climatic conditions in the Guadalupe Estuary prior to the storm were relatively average with salinity around 10 salinity units prior to the storm. As the storm approached, storm surge pushed salinities over 30 with in-rushing sea water. Salinities then dropped as the storm passed and the rain swollen rivers began to flow. Salinity dropped to zero within 7 days of the storm and stayed at that level for over a week. The combination of low oxygen and low salinity caused a massive die off of bottom living organisms. Water column conditions returned to normal after about two weeks, but bottom dwelling organisms did not return to normal until 9 months later. Working with other scientists who studied the storm effects, the information was communicated to State resource managers, industrial water users, and broad groups of concerned community members, because the information is important for understanding the effects of floods and large freshwater inflow events on bay and estuary health. The information is being used by Stakeholder groups responsible for recommending inflow standards for bays and estuaries. Many students were trained during project including four doctorate, two masters, undergraduate, and high school students. Last Modified: 12/09/2019 Submitted by: Paul Montagna