The depth from the surface to the bottom of a well can easily be measured with the help of a tape measure (in most cases 10 meters will do!). At the end of the tape measure you can attach a plumb bob with a little snap hook.
Measure the depth from the upper edge of the well to its bottom. After that, you measure the height of the superstructure from the ground to the upper edge. The depth of the well is actually the depth from the upper edge to the bottom minus the height of the superstructure.
This is the current state. Probably there’s some low sludge on the bottom.
The diameter of the wellhead above the ground can often easily be measured. By this we mean the inner diameter of the opening at the same height of the upper edge. To do this efficiently, you should use a yardstick.
We recommend you to stay focused when measuring the well. There are several risks, both above (e.g. falling into the well with possible wounds or even drowning) as well as in the well (suffocation, drowning, walls coming loose, objects falling into the well etc.). Safety precautions may prevent you from filling in this card completely, but… safety first!
Of course, there are also minor risks such as dropping objects into the well. A treble can be useful to recuperate fallen objects. Attach it to a rope.