Tag Archives: water footprint

Proposed Water Footprint LCA considers water scarcity

Arjen Y. Hoekstra. A critique on the water-scarcity weighted water footprint in LCA Ecological Indicators 66 (2016) 564–573

The water footprint (WF) has been developed within the water resources research community as a volumetric measure of freshwater appropriation. The concept is used to assess water use along supply chains, sustainability of water use within river basins, efficiency of water use, equitability of water allocation and dependency on water in the supply chain. With the purpose of integrating the WF in life cycle assessment of products, LCA scholars have proposed to weight the original volumetric WF by the water scarcity in the catchment where the WF is located, thus obtaining a water-scarcity weighted WF that reflects the potential local environmental impact of water consumption. This paper provides an elaborate critique on this proposal. The main points are:

(1) counting litres of water use differently based on the level of local water scarcity obscures the actual debate about water scarcity, which is about allocating water resources to competing uses and depletion at a global scale;

(2) the neglect of green water consumption ignores the fact that green water is scarce as well;

(3) since water scarcity in a catchment increases with growing overall water consumption in the catchment, multiplication of the consumptive water use of a specific process or activity with water scarcity implies that the resultant weighted WF of a process or activity will be affected by the WFs of other processes or activities, which cannot be the purpose of an environmental performance indicator;

(4) the LCA treatment of the WF is inconsistent with how other environmental footprints are defined; and

(5) the Water Stress Index, the most cited water scarcity metric in the LCA community, lacks meaningful physical interpretation.

It is proposed to incorporate the topic of freshwater scarcity in LCA as a “natural resource depletion” category, considering depletion from a global perspective. Since global freshwater demand is growing while global freshwater availability is limited, it is key to measure the comparative claim of different products on the globe’s limited accessible and usable freshwater flows.

Application of the “Water Footprint” as an Assessment Tool

The concept of a “water footprint” is not universally accepted as a viable approach to setting policy. In the case of water, either you have it or you don’t. It is misleading to think that because 2 countries have shared water resources a “water footprint” calculation will make it any easier for 2 countries the share water resources. The “water footprint” values of 2 countries are not directly comparable even at the commodity-level because of differences in underlying societal values, beliefs and practices. Water utilization (e.g. water footprint) between countries may or may not result in peaceful cooperation in sharing water sources. A “water footprint” calculation may simply make it easier for countries to fight with each other over water. Comparing water use gallon for gallon is to consider water as money, dollar for dollar, regardless of how the water (or dollar) is used. Disagreements and disputes over how much water is needed will continue.

“Water footprint” calculations could be a useful tool. But it could also result in even more and sharper disputes. This study presents a reasonable approach to apply the “water footprint” as an assessment tool and not as a regulatory construct [nor an instrument of water law]. In all cases it is essential to calculate a “water footprint” using hard data.

Osama Sallam. Water footprints as an indicator for the equitable utilization of shared water resources: (Case study: Egypt and Ethiopia shared water resources in Nile Basin). Journal of African Earth Sciences. Dec2014, Vol. 100, p645-655.

The question of “equity.” is a vague and relative term in any event, criteria for equity are particularly difficult to determine in water conflicts, where international water law is ambiguous and often contradictory, and no mechanism exists to enforce principles which are agreed-upon. The aim of this study is using the water footprints as a concept to be an indicator or a measuring tool for the Equitable Utilization of shared water resources. Herein Egypt and Ethiopia water resources conflicts in Nile River Basin were selected as a case study. To achieve this study; water footprints, international virtual water flows and water footprint of national consumption of Egypt and Ethiopia has been analyzed. In this study, some indictors of equitable utilization has been gained for example; Egypt water footprint per capita is 1385 CM/yr/cap while in Ethiopia is 1167 CM/yr/cap, Egypt water footprint related to the national consumption is 95.15 BCM/yr, while in Ethiopia is 77.63 BCM/yr, and the external water footprints of Egypt is 28.5%, while in Ethiopia is 2.3% of the national consumption water footprint.  The most important conclusion of this study is; natural, social, environmental and economical aspects should be taken into account when considering the water footprints as an effective measurable tool to assess the equable utilization of shared water resources, moreover the water footprints should be calculated using a real data and there is a necessity to establishing a global water footprints benchmarks for commodities as a reference.