The following pictures give some idea how much the tank has gone down since March, when it was already low.
March 20 to April 26.
The top image was taken of a small group of pelicans that visited the tank on March 20. The next image was taken April 26, at a very different angle, but the pelican picture was roughly in the yellow box.
April 26 to November 26.
The three images below are from April 26, August 16 and November 26. The angle is roughly the same — compare the trees above the bank. Highlighted are features from the shoreline,a small stump (red box) and a large stone (yellow box).
