Minnesota’s aquifers, streams, lakes, and wetlands are sustained by a balancing act between precipitation and these parts of the hydrologic system. In the absence of human intervention, ground water and surface waters exist in a state of approximate equilibrium. A change in one part of the system, whether due to natural climatic variation or withdrawal of surface water or ground water, results in a balancing response in another part of the system. The rate of system response to change is variable, specific to local conditions, and much slower for ground water than for surface water (except in karst). In some cases, the system may rebalance itself in response to change (such as additional ground-water withdrawal) in months to years. In other cases, the system may adjust very slowly in generations. 

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