Why is Arba Minch, Ethiopia called 'Forty Springs' and what is the significance?

I'm curious about the origin and meaning of the name Arba Minch in Ethiopia. The name translates to 'Forty Springs,' but I'd like to understand: 1. Why is the number 40 significant to this location? 2. What is the historical or cultural background of this name? 3. Are there actually forty springs in the area, or is there a symbolic meaning? 4. What role does this place play in Ethiopian culture or geography? I'm interested in learning more about the place and its naming history.