This Research in Action article was provided to Live Science in partnership with the National Science Foundation.
Water is a critical resource in Florida, where freshwater for communities and farms often is scarce or — during tropical storms — overabundant. In times of high water demand or during storm surges, seawater can intrude into the Florida's aquifers, potentially contaminating the state's water supply.
Some of Florida's vulnerable aquifers are situated in karst landscapes. Karst is a type of landscape that is formed from the dissolution of soluble rocks, including limestone. (On ancient seafloors hundreds of thousands of years ago, burrowing shrimp first created the holes in the limestone that would eventually form aquifers. Over time, the rocks dissolved, increasing the diameters of the burrowed holes.)
To get a better sense of the risk of seawater intrusion into Florida's karst aquifers, Michael Sukop and Sadé Garcia from Florida International University, and Kevin Cunningham of the United States Geological Survey, studied how groundwater flows through one type of karst in South Florida's limestone aquifers.
The researchers worked with experts at the Texas Advanced Computing Center (TACC) to visualize groundwater flowing through these holes. Combining fluid dynamics calculations with computed tomography (CT) data and other imaging techniques, they created 3D animations of groundwater flowing through core samples of karst limestone collected in the region, specifically investigating the rock's permeability.
The visualizations took advantage of the extreme processing power of the National Science Foundation-supported Stampede supercomputer, which is located at the Texas Advanced Computer Center at the University of Texas at Austin. They were based on a method called ray tracing, which seeks to simulate the path and interactions of light in a given environment and produces high quality images that faithfully represent physically-based phenomena.
Using ray tracing to render streamlines (seen in blue and white) and isosurfaces (yellow) greatly improves depth perception in the visualizations and better illustrates the flow of fluid through the thumb-sized holes visible in the limestone.
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