Unsaturated zone

{
  "id": "MLC-T-ENV-029191",
  "term": "Unsaturated zone",
  "field": "Environment",
  "term_source": "Unsaturated Zone",
  "definition": "1. The zone between land surface and the capillary fringe within which the moisture content is less than saturation and pressure is less than atmospheric. Soil pore spaces also typically contain air or other gases. The capillary fringe is not included in the unsaturated zone.\n\n2. The zone between the land surface and the water table. It includes the root zone intermediate zone, and capillary fringe. The pore spaces contain water, as well as air and other gases at less than atmospheric pressure. Saturated bodies, such as perched groundwater, may exist in the unsaturated zone, and water pressure within these may be greater than atmospheric. Also known as vadose zone.\n\n3. The area between the land surface and water table in which the pore spaces are only partially filled with water.\n\n4. The area above the ground water level or water table where soil pores are not fully saturated, although some water may be present.\n\n5. An underground geologic layer in which pores and fractures are filled with a combination of air and water.\n\n6. The area above the water table where soil pores are not fully saturated, although some water may be present.\n\n7. The zone immediately below the land surface where the pores contain both water and air, but are not totally saturated with water. These zones differ from an aquifer, where the pores are saturated with water.\n\n8. The zone between the land surface and the water table.",
  "subject": "Water",
  "references": [
    "Underground Storage Tank Sites Guide Glossary; Office of Underground Storage Tanks Technical Terms; Glossary of Technical Terms: Office of Underground Storage Tanks",
    "Leaking Underground Storage Tanks Sites Glossary",
    "Drinking Water Technical & Legal Terms",
    "Private Wells Glossary",
    "Superfund for Students and Teachers Glossary",
    "Terms of Environment",
    "USGS Water Science Glossary of Terms",
    "40 CFR 260.10 (CFR 2013)"
  ],
  "url": "https://mlchart.com/terminology/environment/unsaturated-zone/"
}