I'm glad Brad stepped in here. You definitely need to consider the actual lift requirement. You also mentioned that your spring feeds a hole that you dug. How quickly does the spring fill the hole and what are the chances of the hole being emptied too quickly by the pump? (No water = burned out pump!) You might need a float switch to cycle the pump on/off based on the water supply. And if that were the case, I'd probably put a couple of batteries (two 12v in series) down there by the pump.