The Chattooga River is one of the oldest river beds in North America, and is one of the last free-flowing major rivers in the south east United States. This particular feature is the last rapid through a section called "The Narrows" on section 3 of the Chattooga.
It is characterized by several above-water boulders and an unusually large 'pothole' just below a bottle-necked narrow stretch of river.
A pothole is a huge circular underwater hole formed by the combined force of swirling water, pebbles and stones carving through the bedrock. THis particular pothole is said to be large enough to drive a Volkswagen 'Beetle' through. No one knows how deep this particular pothole is because it is clogged with debris, including whole tree trunks that are visible at low water. They form an entrapment risk for swimmers, should they be unfortunate enough to have to swim the rapid.
The geologic features force river water to swirl in a characteristic 'whirlpool' fashion, especially during floods, that literally sucks debris into the pothole - hence the name of the rapid, the 'The Eye of God'.
There are two ways to successfully navigate the rapid, depending on the water level. The most notable above-water boulder in the rapid is directly above the pothole and in the center of the river. At low water, rafts can easily take a clear path to the right of this boulder and marvel at 'The Eye of God' as they pass. At lower water levels, the whirlpool phenomenon is not visible, though rafts can still surf in the rapid's hydraulic and entrap swimmers in the pothole's debris. Therefore, taking the path to the left of the boulder, through 'The Eye of God' is discouraged if the right-hand path is available.
At high water levels (measured in inches and feet locally, check with guide companies for advice), the river-right path can become inaccessible and rafts must take the left-hand line. The whirlpool phenomenon is clearly visible. To pass over 'The Eye of God', a raft should skirt the edge of the whirlpool and use the speed of the swirling current, the skill of the guide, and the strength of its paddlers, to build enough momentum to flow out of the rapid's hydraulic pull.
Though not a necessarily difficult maneuver, as the same strategy applies to many 'sticky' hydraulic formations, the risk to any/all swimmers of becoming trapped and/or entangled in the rapid elevates it to Class 4 at high water.