Groundwater Information Center
Although surface water and groundwater appear to be two distinct sources of water, they are not. Surface water and groundwater are basically one singular source of water connected physically in the hydrologic cycle.
If groundwater levels are above water levels in adjacent streams, the groundwater system will discharge water to the stream and increase flow in the stream. When groundwater levels are lower, however, water will leave the stream to recharge the groundwater and decrease flow in the stream. When groundwater is near the surface it creates wetlands and other similar habitat.
When groundwater discharges into an adjacent stream, it is called a gaining stream and when stream water recharges surrounding groundwater, it is called a losing stream. Knowledge of this groundwater-surface water interaction reveals that changes in either the surface water or groundwater system will affect the other. Effective management requires consideration of both water sources as one resource. With that in mind, more understanding and protection of groundwater, especially from contamination and overuse, is needed to increase the overall water supply. Monitoring and evaluation must be continued to gain the understanding needed so that future groundwater issues are not overlooked or misunderstood.
