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M. B. Johnson and M. Mehrvar
winery cannot control the WF embedded in these materials. Conversely, if the objective is to reduce the overall WF of a product, including these indirect factors may
allow decisions to be made to source these materials from alternative suppliers who
have implemented their own in-house water stewardship initiatives to reduce their
production-related WF. One special case that must also be considered for winemaking involves wineries that do not grow their own grapes and/or supplement the
grapes from their vineyard with those grown elsewhere. Because the grapes are a
direct ingredient in the wine-making process, the WF associated with their production should be considered a factor contributing to the direct WF of the wine produced,
no matter where they are grown.
Where possible, WF assessments should be based on multiple years’ worth of data
to develop a more accurate estimate. A multi-year approach can smooth out annual
variations in non-controllable factors, particularly local weather patterns during the
growing season and their effects on irrigation and pest-control needs in the vineyard
as well as overall grape berry yield. It is also often advantageous to assess the WF in
terms of both a functional unit of product (L/U F ) as well as per unit time (e.g. L/yr).
For example, Saraiva et al. [54] reported significant year-to-year increases in winery
WF reported in terms of L/U F (+33% and +32% for blue and grey WF, respectively),
despite small reductions in both water consumption (−3%) and pollutant loading
(−7%). Inspection of the available data indicated that a significant decrease in yearto-year wine production (−30%) was the cause of the increase in the WF as reported
in L/U F rather than changes in water usage.
The WF concept can be used as a benchmarking tool to compare the performance
of subject facility(ies) to other comparable facilities [28]. However, direct “apples
to apples” comparisons can only be made when factors specific to the winery(ies) in
question (climate, soil type, size) and WF assessment approach (extent of the system
boundary, methodology used, WF components (green, blue, grey) included) are also
comparable. For example, the performance of a vineyard in an area of Argentina that
sees <250 mm/yr of rain cannot be assessed against the viticultural stage green and
blue WFs of a vineyard in New Zealand that receives over 1,000 mm/yr. Due to the
variability in conditions from winery to winery, selecting facilities that can be used
for comparison purposes is difficult, especially given the numerous factors that can
affect overall WF. Some significant site-specific factors that should be considered
prior to comparing the WF of a winery against benchmark facilities are presented in
Table 4.
In terms of methodology, the water-balance approach for green and blue WFs
might be best suited to regional assessments, since the operation of the wineries
would have a combined impact on water resources in a geographic area [27, 28].
The consumptive approach would be better suited for benchmarking comparisons
between wineries and/or developing a performance baseline to prioritize and quantify
improvements achieved as operational and/or capital upgrades are implemented.
As noted above, the green and blue WFs provide a quantifiable measure of the
amount of water that is abstracted from the environment during the production of a
product. Conversely, the grey WF is more conceptual in nature: it is a measure of
the virtual volume of water already present in the environment that must be used to
M. B. Johnson and M. Mehrvar
winery cannot control the WF embedded in these materials. Conversely, if the objective is to reduce the overall WF of a product, including these indirect factors may
allow decisions to be made to source these materials from alternative suppliers who
have implemented their own in-house water stewardship initiatives to reduce their
production-related WF. One special case that must also be considered for winemaking involves wineries that do not grow their own grapes and/or supplement the
grapes from their vineyard with those grown elsewhere. Because the grapes are a
direct ingredient in the wine-making process, the WF associated with their production should be considered a factor contributing to the direct WF of the wine produced,
no matter where they are grown.
Where possible, WF assessments should be based on multiple years’ worth of data
to develop a more accurate estimate. A multi-year approach can smooth out annual
variations in non-controllable factors, particularly local weather patterns during the
growing season and their effects on irrigation and pest-control needs in the vineyard
as well as overall grape berry yield. It is also often advantageous to assess the WF in
terms of both a functional unit of product (L/U F ) as well as per unit time (e.g. L/yr).
For example, Saraiva et al. [54] reported significant year-to-year increases in winery
WF reported in terms of L/U F (+33% and +32% for blue and grey WF, respectively),
despite small reductions in both water consumption (−3%) and pollutant loading
(−7%). Inspection of the available data indicated that a significant decrease in yearto-year wine production (−30%) was the cause of the increase in the WF as reported
in L/U F rather than changes in water usage.
The WF concept can be used as a benchmarking tool to compare the performance
of subject facility(ies) to other comparable facilities [28]. However, direct “apples
to apples” comparisons can only be made when factors specific to the winery(ies) in
question (climate, soil type, size) and WF assessment approach (extent of the system
boundary, methodology used, WF components (green, blue, grey) included) are also
comparable. For example, the performance of a vineyard in an area of Argentina that
sees <250 mm/yr of rain cannot be assessed against the viticultural stage green and
blue WFs of a vineyard in New Zealand that receives over 1,000 mm/yr. Due to the
variability in conditions from winery to winery, selecting facilities that can be used
for comparison purposes is difficult, especially given the numerous factors that can
affect overall WF. Some significant site-specific factors that should be considered
prior to comparing the WF of a winery against benchmark facilities are presented in
Table 4.
In terms of methodology, the water-balance approach for green and blue WFs
might be best suited to regional assessments, since the operation of the wineries
would have a combined impact on water resources in a geographic area [27, 28].
The consumptive approach would be better suited for benchmarking comparisons
between wineries and/or developing a performance baseline to prioritize and quantify
improvements achieved as operational and/or capital upgrades are implemented.
As noted above, the green and blue WFs provide a quantifiable measure of the
amount of water that is abstracted from the environment during the production of a
product. Conversely, the grey WF is more conceptual in nature: it is a measure of
the virtual volume of water already present in the environment that must be used to