3.5.3 Surface-Groundwater Interface

The surface-groundwater interface is a transitional region between surface water and adjacent aquifers.  This zone plays a vital role in controlling exchange of water, chemical constituents and contaminants between surface and groundwater.  These zones are spatially fluctuating, and influenced by a number of processes at various scales.  These zones are often functionally important to biotic integrity of water resources, such as providing for nutrient and dissolved oxygen exchange and refuge for certain organisms during drought conditions.  The hyporheic zone between a stream and groundwater can extend hundreds of feet from a stream, and processes within this zone can significantly influence streamflow, water quality, and biotic integrity.

The surface-groundwater interface has only recently been the focus of research and policy discussion.  Findings to date emphasize that groundwater and surface water are not functionally separate but rather are components of dynamic, connected systems that require a holistic management approach.