What would happen to the water level in the aquifer if you continue to add water?

The aquifer will become saturated and it will take the path of least resistance to the nearest body of water.

Explanation: Gravity will pull water down through the sand, gravel and clay layers in the soil until it reaches bedrock, where it can absorb no more moisture. Eventually, gravity pulls the underground water to join the nearest river, stream, lake or ocean. If the bottom is solid rock and the water has no downward path to take, it will pool. This is one way that lakes form.