Today, the area of the Gulf of Mexico known as the Trinity River Paleovalley is submerged underwater, but 20,000 years ago, when ice covered immense areas of the planet, sea levels were significantly lower, meaning the valley was not underwater, but rather a lively coastline through which the Trinity River ran. 

Today, researchers from University of Texas at Austin’s Institute for Geophysics are working to map the curves of that long lost river in hopes it will provide some clues into the future of our own warming climate. Looking at how water filled in this coastal region thousands of years ago provides an indication of how rising seas will affect today’s coastlines as sea levels rise. 

The researchers spend the day aboard a boat off the coast of Houston, collecting samples which they scan for sandy particles. Sand, rather than mud, indicates that they have found part of the ancient riverbed. 

Another reason the researchers are interested in these sandy depths is for potential coastal restoration. Texas beaches have been replenished with sand 89 times since the 1950s as erosion carries sand away, but finding sand that matches natural ecosystems and doesn’t detract from another habitat when extracted is tough.

The researchers are optimistic that this sandy section of the gulf floor could provide sand for coastal restoration that goes beyond re-sanding. They hope that if approved, they can use the sand sourced from the gulf to restore dunes and marshes that will more effectively insulate the shore from rising seas and storm surges.