Groundwater is a critically important source of water for rivers, wetlands, lakes and terrestrial ecosystems, helping to maintain water level, temperature, oxygen content and chemcals required by plants and animals. Groundwater commonly supplies summer flow with cool, oxygenated water and creates focal areas of groundwater discharge that provide important local habitats for the survival of certain species or aquatic food webs in warm summer rivers.
As environmental flows are partially or fully supplied by groundwater discharge, environmental flows can be seriously impacted by abstraction from groundwater in the river basin. Rivers, especially in temperate zones, are sustained by groundwater discharge during the dry season. Additionally, springs are generated from groundwater outflow and can give rise to significant rivers, which are very sensitive to groundwater exploitation