This is an Relift system from a reservoir, and the water is kept at a certain level by a huge submerged pipe, gravity fed. Its a complicated undertaking here, it sits by a highway. To keep from flooding the highway it steps down to a lower canal. This HOLE happens when water is a couple inches higher than the pipe, and drains into the lower canal. Its not a whirlpool, it just goes straight down. …I’ve tried for 50 years to get this on film! The first time I saw this, I was 6 years old on my dads rice farm in S. Arkansas, USA. It scared me and fascinated me at the same time. I wandered too close to the edge, the bank caved in and I was IN the water being pulled toward this. The current is very strong, and the ‘Sucking Noise’ is loud and is beyond describing! I screamed. I had my feet braced on the pipe edge and holding onto a bush. The bush was losing. My dad jumped in and saved me. We BOTH had nightmares after that! The pipe is 3 feet wide, and would fit a person. I’ve seen it a couple times since, but had no camera. Yesterday I finally did!! (2-27-2013). I stood, again transfixed, and pohoto’d this, in a brisk freezing wind. But was shaking mostly from fear. I was again a frightened 6 yr old kid. And yes, I DID have nightmares last night. Taken on the Grand Prairie of E. Arkansas, with a SanyoVPC-E2100, straight from the camera.