Since the Nationís worries over water resources as well as the environment increase, the importance of considering ground water and surface water as just one resource has become increasingly evident. Issues related to water supply, water quality, and degradation of aquatic environments is reported on frequently. The interaction of ground water and surface water has been shown to be a significant concern in many of these issues. For example, contaminated aquifers that discharge to streams can result in long-term contamination of surface water; conversely, streams can be a major source of contamination to aquifers.

Surface water generally is hydraulically connected to ground water, but the interactions are difficult to observe and measure and commonly have been ignored in water-management considerations and policies. Many natural processes and human activities affect the interactions of ground water as well as surface water. The purpose of this report is usually to present our current understanding of these processes and activities as well as limitations in our knowledge and ability to characterize them