Open cuts, canals, like this are created by the flow of water through trunks between marshes. When the water is low on one of the sides an open trunk creates a strong stream of moving water. Over time the current creates a cut in the land.
This particular trunk also moves water under a side road in the ACE Basin. A few years ago we would walk this area photographing the Wood Storks that fished here. Now, no walking or Storks. The land has changed drastically.