Consumptive Use of Water

Consumptive use represents the share of extracted water that does not return to the same basin in either quantity or quality suitable for reuse. It includes water that evaporates, becomes part of products, or is transferred to another basin.

Formula

Consumptive use = Total withdrawal – Return to the local water body

Key impacts

• Actual water stress: only consumptive use reduces available water; treated return flows can be reused.
• Blue water scarcity: calculated based on consumed—not withdrawn—water.

Reduction strategies

• Drip and deficit irrigation: reduces evaporation by 30%.
• Closed-circuit cooling towers: reduce industrial consumption by 90%.
• Managed aquifer recharge: captures stormwater for groundwater replenishment.

Sectoral values

• Irrigated agriculture: 70%
• Thermal power (wet cooling towers): 2%
• Copper mining: 45%
• Textile industry: 8%

Importance

• Determines the real contribution to water stress.
• Influences calculations of blue water scarcity and the AWARE factor.

Relationship with water neutrality and AWARE

Water neutrality requires offsetting consumptive use weighted by the AWARE factor to ensure balance in water-stressed basins.

Additional reduction measures

• Covering open channels → 25% evaporation savings.
• Scheduled deficit irrigation → 15% consumption reduction with no yield loss.
• Closed-loop industrial cooling → 90% reduction in consumptive use.

Quantifying consumptive use is essential for prioritising efficiency investments and meeting corporate water-neutrality goals.