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GCOS Land ECV - Ground Water

It is estimated that groundwater accounts for about 30 % of the world’s total freshwater resources, including those locked in snow and ice, and is by far the largest available reservoir of liquid freshwater. Today, it is the source of about one third of global water withdrawals. Estimates of the number of people who depend on groundwater supplies for drinking range from 1.5 billion to 3 billion. Global groundwater abstraction has at least tripled over the past 50 years, much more so in some regions, and is used mainly for agriculture. The relative increase in groundwater use over recent decades has been larger than that of surface-water use. Climate change affects groundwater recharge rates through changes in precipitation and evapotranspiration. However, attributing observed groundwater change to climate change is difficult because of land-use change and groundwater abstraction, and the extent to which groundwater abstraction has already been affected by climate change is not known. Climate change can also affect groundwater through saltwater intrusion in coastal aquifers as sea level rises. This can be observed by a change in the electrical conductivity of groundwater, but attribution is again complicated by abstraction, as withdrawal of freshwater from the ground may draw more-saline water into the aquifer.

Product Requirements:

  • Groundwater Volume Change:
    • Frequency:  Monthly
    • Resolution:  100 km
    • Required Measurement uncertainty:  10 cm
    • Stability (per decade unless otherwise specified):  TBD
    • Standards/References:  ISO 5667-11:2009
    • Entity (in situ):  WHYCOS
  • Groundwater Level:
    • Frequency:  Weekly
    • Resolution:  Per well
    • Required Measurement uncertainty:  1 cm
    • Standards/References:  ISO 5667-11:2009
    • Entity (in situ):  WHYCOS
  • Groundwater Recharge:
    • Frequency:  Weekly
    • Resolution:  Per well
    • Required Measurement uncertainty:  10 % (relative)
    • Standards/References: ISO 5667-11:2009
    • Entity (in situ):  WHYCOS
  • Groundwater Discharge:
    • Frequency:  Weekly
    • Resolution:  Per well
    • Required Measurement uncertainty:  10 % (relative)
    • Standards/References: ISO 5667-11:2009
    • Entity (in situ):  WHYCOS
  • Wellhead Level:
    • Frequency:  Weekly
    • Resolution:  Per well
    • Required Measurement uncertainty:  1 cm
    • Standards/References:  ISO 5667-11:2009
    • Entity (in situ):  WHYCOS
  • Water Quality:
    • Frequency:  Weekly
    • Resolution:  Per well
    • Required Measurement uncertainty:  TBD
    • Standards/References:  ISO 5667-11:2009
    • Entity (in situ):  TBD

Networks:

Data Sources: