Water Footprint

Question 1

The global water crisis and water scarcity

Answer 1

• Only 1% of the global water reserves are useable freshwater and there are huge differences in the regional distribution
• 3 of 10 people (2.1 billion) do not have access to safe drinking water
• 6 of 10 people (4.5 billion) do not have access
  to basic sanitation service

SDG6: clean water and sanitation

• Billions of people still lack safe water, sanitation and handwashing facilities
• Water pollution is worsening
• Water and sanitation lack funding
• Governance structures are weak and fragmented
• Agriculture places enormous stress on water, but could be part of a water saving solution
• Capacity is insufficient
• Ecosystems and their services are in continuous decline

Question 2

Virtual water

Answer 2

• Water consumed/polluted along supply chains of products and organization:

Blue water : Consumption of ground and surface water
- Blue water consumption: “Loss” of blue water for originating river basin due to evapotranspiration, product integration or discharge in other basins or the sea

Green water: soil moisture available for plants
- Green water consumption: “Loss” of green water due to evapotranspiration of rain water by plants

Gray water: polluted blue water
- Gray water footprint: water polluted by waste water, measured by the volume of water required to dilute waste water until quality standards are reached

Question 3

Limits of virtual water

Answer 3

• Relevance of green water is controversial:
  – Only locally available for plants, not for surrounding ecosystems or humans
  – Green water consumption should be seen in comparison to evapotranspiration of
  natural land net green water footprint
• Grey water (dilution water) is dependent on quality standards chosen
• Amounts of blue, green and grey water consumption are usually added Implication of equality for which a scientific rationale is lacking
• Volume of water consumption does not allow for any statement regarding impacts on human health and ecosystems

Question 4

Water footprint according to ISO

Answer 4

“A water footprint assessment addresses the potential environmental impacts related to water associated with a product, process or organization.”

Water footprint = „water shoesize“ x weight

Water footprint: Impacts of water use along a product life cycle

Water shoesize: Volume of consumed water

Weight:
* Lokal water scarcity
* Lokal sensitivity of population
(wealth, medical care,
* Lokal sensitivity of ecosystems
* Type of watercourse
* Water quality
* Time of water use (dry/wet season)

Question 5

Water accounting & vulnerability evaluation (WAVE)

Answer 5

• Model quantifies local water scarcity in > 8,000
  river basins around the globe in monthly resolution
• Denotes the risk to deprive other users of using freshwater when consuming
  water in a river basin

Question 6

Mitigating water stress

Answer 6

-> mitigate= abschwächen/entschärfen

• Use water footprint results to mitigate water stress along the supply chain:

– Water Stewardship: Take collective action at local hotspots in global supply chains with suppliers and stakeholders

– Eco design : Analyze a product’s water use along its life cycle in design phase –> Optimization by water efficient
material and design choices

– Sustainable procurement : Purchase of water efficient materials & improve water management at suppliers