sentence2_structure: You<>call<>water that flows out of the ground$$$water<>flows<>out of the ground$$$an aquifer<>meets<>the surface<>the ground
sentence1: The problem is that safe yield ignores the complex relationships between surface water (lakes, streams, springs, and marshes) and groundwater (water found in underground rock formations called aquifers).
sentence2: You call water that flows out of the ground where an aquifer meets the surface a(n) spring.
question: What do you call water that flows out of the ground where an aquifer meets the surface?