Grundvattnet

Grundvattnet, or groundwater, is water stored underground in the pores of soil and sediment and in fractures of rock. It is a major component of the Earth's freshwater and a key source for drinking water, irrigation, and industry. Groundwater originates from rainfall and surface water that infiltrates the soil, gradually filling aquifers; it recharges in recharge zones and discharges at springs, rivers, lakes, or the oceans.

The part of the subsurface that holds groundwater is the saturated zone; the water table marks the upper boundary of that zone. Groundwater moves slowly through porous rock and soil, governed by hydraulic properties of the underground formations. The availability and quality of groundwater depend on geology, climate, land use, and protection from contamination.

Quality and risks: Groundwater can be naturally soft or hard, contain dissolved minerals, and may be contaminated by human activity such as agricultural runoff (nitrates, pesticides), industrial spills, leaking septic systems, or saltwater intrusion in coastal areas. Protection and remediation are important to maintain safe supplies.

Management: Sustainable extraction, monitoring of levels and quality, and protection of recharge areas are typical strategies. In many regions, groundwater is regulated to prevent over-extraction and to reduce contamination, while artificial recharge and well management help stabilize supplies during droughts.