Chlorophyll-a concentration (Chl-a), which serves as an estimate for phytoplankton biomass, is a significant environmental indicator for coastal ecosystems. The productive coastal waters have tremendous ecological, economic, and social value for Texas. In August 2017, Hurricane Harvey dumped an excessive amount of freshwater into the Gulf of Mexico within a short period of time, which may have significantly altered the coastal water quality. 

The objective of this study was to evaluate the effects of Hurricane Harvey on Gulf Coast water quality from a perspective of remotely sensed Chl-a concentration levels. To this end, we collected in situ reflectance data using the Analytical Spectral Devices (ASD) HandHeld-2 spectroradiometer at Conductivity, Temperature, and Depth (CTD) sampling sites during three cruise surveys that occurred in 2017 (September and November) and 2018 (March). The Chl-a concentrations were obtained using the fluorometer deployed at the CTD sites. By comparing the in situ measured Chl-a values with the simultaneously collected spectra data, the optimal retrieval algorithm applicable to the operational Moderate-resolution Imaging Spectroradiometer (MODIS) satellite observations (after atmospheric correction) was developed. The algorithm was then applied to satellite data to monitor the spatio-temporal variations of Chl-a before and after Hurricane Harvey. Not only can this study help to evaluate Harvey’s influence on Texas coastal waters, it can also provide an efficient way to continuously monitor the coastal water quality of Texas from space. The methods and results developed in this study will benefit various fields and industries, such as marine biology, environmental protection, commercial fisheries, and others.

Evaluation of the Spatio-temporal Variations of Chlorophyll-a Concentrations Along the Texas Shelf After Hurricane Harvey Using Remote Sensing Techniques

Created in 1999, the Environmental & Water Resources Institute (EWRI) is the recognized leader within ASCE for the integration of technical expertise and public policy in the planning, design, construction, and operation of environmentally sound and sustainable infrastructure impacting air, land and water resources.

[Paper Proceedings](https://doi.org/10.1061/9780784483466)