Water Stress Index Calculator

Calculate the water stress index for a region by comparing total water withdrawals to available renewable supply.

km³/yr
km³/yr

Water Stress Ratio

0.400

Stress Percentage40.0 %
Remaining Supply45.0 km³/yr

Water Stress Ratio vs Total Annual Withdrawals

Water Stress Index

The water stress index measures how much of a region's available water is being used. Higher ratios indicate greater pressure on water resources.

Formula

Water Stress = Total Withdrawals / Renewable Supply

Thresholds

  • < 0.10: Low stress
  • 0.10 - 0.20: Low-to-medium stress
  • 0.20 - 0.40: Medium-to-high stress
  • > 0.40: High stress (water scarcity)
  • > 0.80: Extremely high stress
  • Example Calculation

    A region withdraws 30 km³/year from a renewable supply of 75 km³/year.

    1. 01Stress ratio = 30 / 75 = 0.400
    2. 02Stress percentage = 40.0%
    3. 03Remaining supply = 75 - 30 = 45 km³/year
    4. 04At 40%, this region is at the high stress threshold

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