Water footprint assessment of citrus production in South Africa: A case study of the Lower Sundays River Valley
- Authors: Munro, Samantha A , Fraser, Gavin C G , Snowball, Jeanette D , Pahlow, Markus
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/69240 , vital:29463 , https://doi.org/10.1016/j.jclepro.2016.06.142
- Description: Water footprint assessment is a developing method that is being increasingly applied to quantify water use, prioritise reductions, assess sustainability and provide information to achieve sustainable, efficient, and equitable water use. The objectives of this paper were to conduct a water footprint assessment of primary citrus production within the Lower Sundays River Valley in South Africa using local, high-resolution data and to examine indicators (water scarcity, pollution, efficiency, productivity and access) to determine the sustainability of blue, green and grey water footprints of a wet, dry and average year. Lemons were found to have the lowest blue and combined green-blue water footprint per ton of production across all climatic years, followed by soft citrus, valencias and navels. Valencias had the lowest, and navels the highest grey WF (relating to inorganic nitrogen). Lemons, despite their high crop water and fertiliser requirements, were regarded more economically efficient in comparison to valencias, soft citrus and navels, in that they provided higher net income and more employment hours per m3 of water in comparison to other citrus crops. In an average season, lemons generated approximately 39% more income per m3 of water than navels, despite navels being the dominant cultivar. Blue water consumption for citrus in the catchment was calculated to be 58.7 Mm3 for an average season and 89.2 Mm3 for a dry season. Due to an inter-basin transfer scheme, no physical water scarcity occurred, and both environmental and basic human needs are met. Water pollution levels related to nitrogen however, exceeded the assimilative capacity of the run-off in dry years. The area also experiences institutional and infrastructural scarcity and 14% of the population do not have access to piped water. Stakeholders and governments may use the results of water footprint assessments to determine the status of river basins, make evaluations for future water usage and the potential impacts of expanding agriculture and different management strategies. Including environmental and socio-economic indicators will also improve the integrity of water footprint assessments.
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- Date Issued: 2016
Water footprint assessment to inform water management and policy making in South Africa
- Authors: Pahlow, Markus , Snowball, Jeanette D , Fraser, Gavin C G
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68813 , vital:29327 , http://dx.doi.org/10.4314/wsa.v41i3.02
- Description: Publisher version , One method to inform decisions with respect to sustainable, efficient and equitable water allocation and use is water footprint assessment (WFA). This paper presents a preliminary WFA of South Africa (SA) based on data for the period 1996-2005. Crop production was found to contribute about 75% of the total water footprint of national production. The total water footprint of crop production is mainly composed of five crops: maize, fodder crops, sugarcane, wheat and sunflower seed, which account for 83% of the crop water footprint. The average water footprint of a South African consumer is 1 255 m3/yr, below the world average of 1 385 m3/yr, and is dominated by the consumption of meat (32%) and cereals (29%). About one fifth of this water footprint of consumption is external to SA. While SA is a net virtual water importer, the virtual water trade analysis revealed that a large share of blue water consumption is related to export. Sustainability concerns are that the major river basins face severe blue-water scarcity for extended periods of the year, and that water pollution levels related to nitrogen and phosphorus were found to be unsustainable in all river basins in SA. Efficient allocation and use of water is investigated by means of comparing the consumptive water footprint to global benchmark values, as well as the economic green- and blue-water productivity and the economic land productivity of the crops cultivated in SA. Furthermore, crops with specific potential for biofuel production are assessed. Lastly, recommendations to address the identified issues are given.
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- Date Issued: 2015