Water Footprint

Definition:

Water Footprint is the amount of avoided water use that ReFED estimates would result from a given food surplus management scenario.

Water Footprint Equation:

Water Footprint = Upstream Gallons Water Use per Ton * ( Sum of Tons Surplus Sent to any Destination other than Donations + 50% * Tons donations )

Equation for Net Benefit of Alternative Scenario:

Net Benefit = Water Footprint of Current Scenario - Water Footprint of Alternative Scenario

The following table includes an example calculation to illustrate this methodology as implemented in the Impact Calculator.

Table 2. Example Calculations Performed to Estimate the Water Footprint of Two Food Surplus Management Scenarios

DATA ITEM	DATA SOURCE OR CALCULATION	EXAMPLE
Sector	User provided	Retail
Food Type	User provided	Produce
Weight of Food by Destination (Current Scenario)	User provided	A grocery retail sustainability manager wants to understand the potential water savings that could be expected from a new technology solution to prevent surplus of fruit and vegetable produce in their stores. They also want to start donating perfectly-good-to-eat produce that is currently being landfill just because it’s past the ‘sell by’ date. Currently, they estimate the following annual breakdown of their produce surplus by destination (Current Scenario): 20 tons donations 30 tons composting 50 tons landfill ——————————— 100 tons total annual produce surplus
Weight of Food by Destination (Alternative Scenario)	User provided	Based on a recent analysis from a hired consultant, they estimate that 50% of the food they’re currently sending to compost and landfill could be prevention by the new prevention technology. They also think that an additional 5 tons of the food that they’re currently landfilling because it’s past the ‘sell by’ date is perfectly-good-to-eat produce that could be donations instead. This would be the new destination breakdown after implementing the prevention solution and increased donations (Alternative Scenario): 40 tons prevention 25 tons donations 15 tons composting 20 tons landfill _____________________ 100 tons total
Sum of Tons Surplus Sent to any Destination other than Donations	Tons Surplus sent to any of the following destinations: -Animal Feed -Industrial Uses -Composting -Anaerobic Digestion -Not Harvested -Land Application -Incineration -Landfill -Dumping -Sewer	Current Scenario: = 30 tons composting + 50 tons landfill = 80 tons surplus sent to destinations other than donations Alternative Scenario: = 15 tons composting + 20 tons landfill = 35 tons surplus sent to destinations other than donations Note: ReFED assumes that both prevention and donations lead to less production and therefore less water use to produce the food.
Gallons Water Used to Produce Food	Water Footprint Network[2],[3],[5] (See Appendix C for more information)	40,427 gallons of water used to produce 1 ton of produce
Water Footprint of Current Scenario	= Gallons Water Used to Produce 1 Ton of Food * ( Sum of Tons Surplus Sent to any Destination other than Donations + 50% * Tons donations )	= 40,427 gallons of water use per ton * ( 80 tons sent to other destinations * 50% * 20 tons donations ) = 3,638,401 gallons of water used
Water Footprint of Alternative Scenario	= Gallons Water Used to Produce 1 Ton of Food * ( Sum of Tons Surplus Sent to any Destination other than Donations + 50% * Tons donations )	= 40,427 gallons of water use per ton * ( 35 tons sent to other destinations * 50% * 25 tons donations ) = 1,920,267 gallons of water used
Net Benefit	Water Footprint of Current Scenario - Water Footprint of Alternative Scenario	= 3,638,401 gallons - 1,920,267 gallons = 1,718,134 gallons of water use avoided Click here to see this example in the ReFED Impact Calculator.