Employing Input-Output Model to Assess …
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field of water footprint assessment has also emerged as it meets the development
needs of consumption and trade [16].
The WF is a measure of consumptive and degradative freshwater use, as Hoekstra defined. The consumptive WF includes a green component, which refers to the
consumption of rainwater, and a blue component, which refers to the consumption
of surface- or groundwater [15]. The consumption relates to the loss of available
surface water and groundwater in the basin. When water evaporates, flowing back
out of the basin, sinks into the sea, or is incorporated into products, there appears
water loss. The inclusion of the green WF enables the broadening of water resources’
perspective beyond the historical focus of water engineers on blue water [8]. The
degradative WF, the so-called gray WF, represents the volume of water required to
assimilate pollutants entering freshwater bodies [15, 42], which is developed from
the concept of dilution water requirement earlier applied by Postel et al. [32].
Water footprint assessment is an analytical tool that can help understand the impact
of human activities and products on water shortages and pollution and provide corresponding solutions to ensure the sustainable use of freshwater by human activities
and products [31]. Before conducting a water footprint assessment, it is necessary
to set reasonable targets and scopes according to the research purpose, collect and
calculate data, and carry out a sustainable assessment of water footprint on this basis,
and propose targeted response plans.
The water footprint assessment mainly includes four stages.
(1) Set goals and scopes;
(2) Account water footprint;
(3) Sustainable evaluation of water footprint;
(4) Develop a water footprint response plan.
2.2 Water Footprint Assessment Based on Bottom-Up
Method (LCA)
So far, the calculation methods of water footprint mainly include two kinds. One is
a bottom-up calculation method, in which water is “embedded” in product output,
and the product virtual water trade flow analysis is carried out with the help of
a water footprint model. Its advantage is that it is flexible and intuitive, and data
levels can be selected. However, because it is a data-intensive analysis method, it
is not suitable for the national water footprint and is prone to cut off errors. The
assessment based on bottom-up method, starting from the perspective of technology
and production process, comprehensively considers the production of the product and
the requirements in the production process of multi-level raw materials for the sum
of all water resources. This method is widely used in the early and mid-term of water
footprint research where scholars have adopted this method of life cycle analysis in
a series of studies to analyze the water footprint or the issue of virtual water hidden
in a certain industry [23, 29, 36]. In the process of analyzing the water footprint of a
159
field of water footprint assessment has also emerged as it meets the development
needs of consumption and trade [16].
The WF is a measure of consumptive and degradative freshwater use, as Hoekstra defined. The consumptive WF includes a green component, which refers to the
consumption of rainwater, and a blue component, which refers to the consumption
of surface- or groundwater [15]. The consumption relates to the loss of available
surface water and groundwater in the basin. When water evaporates, flowing back
out of the basin, sinks into the sea, or is incorporated into products, there appears
water loss. The inclusion of the green WF enables the broadening of water resources’
perspective beyond the historical focus of water engineers on blue water [8]. The
degradative WF, the so-called gray WF, represents the volume of water required to
assimilate pollutants entering freshwater bodies [15, 42], which is developed from
the concept of dilution water requirement earlier applied by Postel et al. [32].
Water footprint assessment is an analytical tool that can help understand the impact
of human activities and products on water shortages and pollution and provide corresponding solutions to ensure the sustainable use of freshwater by human activities
and products [31]. Before conducting a water footprint assessment, it is necessary
to set reasonable targets and scopes according to the research purpose, collect and
calculate data, and carry out a sustainable assessment of water footprint on this basis,
and propose targeted response plans.
The water footprint assessment mainly includes four stages.
(1) Set goals and scopes;
(2) Account water footprint;
(3) Sustainable evaluation of water footprint;
(4) Develop a water footprint response plan.
2.2 Water Footprint Assessment Based on Bottom-Up
Method (LCA)
So far, the calculation methods of water footprint mainly include two kinds. One is
a bottom-up calculation method, in which water is “embedded” in product output,
and the product virtual water trade flow analysis is carried out with the help of
a water footprint model. Its advantage is that it is flexible and intuitive, and data
levels can be selected. However, because it is a data-intensive analysis method, it
is not suitable for the national water footprint and is prone to cut off errors. The
assessment based on bottom-up method, starting from the perspective of technology
and production process, comprehensively considers the production of the product and
the requirements in the production process of multi-level raw materials for the sum
of all water resources. This method is widely used in the early and mid-term of water
footprint research where scholars have adopted this method of life cycle analysis in
a series of studies to analyze the water footprint or the issue of virtual water hidden
in a certain industry [23, 29, 36]. In the process of analyzing the water footprint of a