Tracking changes in the shape and volume of the shallow seafloor is challenging, especially along coastlines where the water is often clouded with high volumes of suspended sediment. Because we lack regular monitoring in these areas, it's difficult to fully understand how sediment moves along the coast, especially before and after major storms.

To help address this, we developed a method that uses satellite images to estimate the shape of the seafloor in these turbid coastal waters. We, first, determine the ideal conditions resulting in clear days so that we can limit the satellite images we use to those taken on days when the seafloor can be seen through the water column. The method is based on a mathematical relationship between the brightness of satellite pixels from many images and water depths measured from a previous lidar (laser-based) survey.

By applying this method to a series of satellite images from the same area over time, we can track how the seafloor changes. We tested this approach along the Texas Gulf Coast during Hurricane Harvey, revealing that much of the beach sediment lost during the storm was deposited just offshore, changing the shape and volume of nearshore sand bars.