Answer to Question 1
When a lot of water is withdrawn from a well, the water table around it is lowered. This is called drawdown. Drawdown decreases with increasing distance from the well, resulting in a roughly conical depression in the water table, called a cone of depression.
Answer to Question 2
The successful well has penetrated the perched aquifer in this figure. The unsuccessful well is at the same depth, but not within the range of the perched aquifer. Because the perched aquifer is so much higher than the water table, the unsuccessful well would have to be drilled almost twice as deep to reach groundwater.
