This was the end of the main trunk of Trash Compactor Cave and the room for which it is named (Trash Compactor scene: Star Wars Episode IV: A New Hope).
All the debris you see here is floating on water. Notice as we move, how the whole mass ripples. It is through this sump that we suspect a connection to Capshaw. Lee Pearson and Jason Collard later went to the closest spot in Capshaw to see if there was any match to debris types and he found plenty of styrofoam. It's a primitive, but possible effective dye-trace.
This cave was accessed after the May 2010 floods when a swallet finally enlarged enough to allow for human visitation.