Water Footprint Assessment Framework for Grapes: Integrating Remote Sensing, Geospatial and Other Datasets
van Niekerk, A
Van Graan, H
The study aimed at assessing the water footprint (WF) of wine and table grapes produced in selected regions of the Western Cape, as an indicator of sustainability. Access to large production databases and spatial estimates of evapotranspiration for numerous fields, allowed the estimation of WFs for a range in production conditions.
The Global WF Standard (GWFS) approach was used as the basis for developing an improved methodology for WF assessment (WFA). Remote sensing (RS) data, large datasets and look-up tables were used to calculate the blue, green, grey and total WF components. Case studies were conducted in three production regions. WF results were expressed in water use per 750 mL bottle of wine and water use per L of wine. The median WFtotal of wine (field level plus cellar), considering >3 600 fields from three regions, was 647 L of water for 750 mL of wine (863 L/L). It ranged between 480 L/750mL of wine in the Breede River Valley (641 L/L) and 933 L/750mL of wine in the Coastal Region (1 325 L/L).
This study successfully calculated the WF of wine and table grapes in different production regions using spatial data, large production datasets and lookup tables. Integrating large numbers of field level WF estimates into a final product WF estimates, showed the impact of a range in production conditions on the WFs.
Integrating data from various fields into a WF provides insight into the impact of a range in production conditions on the final WFtotal for wine and where improvements are possible. Wine grape yield strongly influences the field level WFtotal for wine grapes. Field level WF contributed most to the WFtotal of wine, but contributions of WFgrey should not be ignored. Placing the actual WFtotal estimates in a financial and environmental context is important.
For the wine industry an article was published in Afrikaans in the Winetech Tegnies (January 2019 in the Winetech Tegnies: Watervoetspoor van Druiwe en Wyn.). An English version of this article is available online in the WineLand magazine and can be downloaded from https://www.wineland.co.za/water-footprint-of-grapes-and-wine/.
For the table grape industry an article appeared in the SA Fruit Journal (SAFJ in Feb/Mar 2019).
It can be downloaded from: https://www.safj.co.za/wp-content/uploads/2019/02/safj-sa-fruit-journal-feb-march-2019.pdf.