University of Tennessee researchers are collaborating with the National Park Service to map the streams of the Big South Fork National River and Recreation Area and the Obed Wild and Scenic River, the Knoxville News Sentinel reports. Their goal is to identify habitat for freshwater mussels and fish, and it involves some pretty unusual technology:

The project uses an innovative underwater video system that takes Global Positioning System (GPS) digital data and stores it continuously on the audio track of the DVD as the kayak floats down river.

Simultaneously, the river’s surface features are recorded using a similar geo-referenced video camera. Images from both video cameras are downloaded into a Geographic Information System (GIS) to produce digital maps that depict the stream in minute detail, above and below the surface.

Watch the short video and see if that doesn’t make it easier to understand.