Grand Gulf Sink

Grand Gulf Sink. Grand Gulf State Park. , Full to Empty, This large chasm called the Sink marks the point where the roof of the cave system stopped collapsing. On a day when Grand Gulf is empty, you can see the bottom of the Sink and a cave opening. The cave is the opening to a tunnel and functions like the drain in your kitchen sink. When you fill up your kitchen sink, all the water leaves the sink through the drain or hole in the bottom. Similarly, all water that fills up Grand Gulf leaves the Gulf through this hole in the bottom of the Sink. After draining from the Sink, the water travels nine miles underground and resurfaces at Mammoth Spring in Arkansas. , How do we know that the water from the Sink comes out at Mammoth Spring?, Scientists use dye trace tests to determine how water flows through cave systems. Dye trace tests involve placing a fluorescent dye into the water and placing charcoal filled packets and test for captured dye. In 1968, a student from West Plains High School performed the first dye trace test here as a science fair project and recovered the dye at Mammoth Spring. In 2013, the Department of Natural Resources' division of Missouri Geological Survey (MGS) performed a detailed dye trace test that confirmed the 1968 finding.