Changing Water Resources and Food Supply in Arid Zones: Tunisia

Virtual-water content of agricultural production and food trade balance of Tunisia

“…This corresponds, for a given agricultural production, to the amount of rainwater consumed during the growing period of the crop. The limits of the classical hydraulic water vision in addressing food security challenges in arid and semi-arid countries have been highlighted in previous articles (Besbes et al, 2010;Chahed, Besbes, & Hamdane, 2011). Furthermore, the concept of 'water security' versus 'water stress' derives from the same hydraulic approach and considers only the potential of water withdrawal.…”

“…The average annual rainfall is around 220 mm, corresponding to 36 km 3 /y of precipitation throughout the country. This average masks huge disparities: (1) spatial heterogeneity, with 1000 mm/y in the north and less than 100 mm/y in the south (Figure 1); and (2) temporal variability-minimum rainfall is onethird the average, and maximum is up to three times the average (Besbes, Chahed, Hamdane, & De Marsily, 2010).…”

“…Direct water needs (for drinking and for industrial and touristic activities) are estimated at 50 m 3 /y per capita, whilst the amount needed for food production is more than 1500 m 3 /y per capita (Besbes et al, 2010). Despite its limited resources, Tunisia has shifted towards mobilizing most of its water resources by way of a large water infrastructure.…”

Tomato value chain analysis in Tunisia : business opportunities : Business opportunities

“…Desert (Saharan) 20-100 Table 4: Annual rainfall in the different bioclimatic zones [7] The potential conventional water resources are estimated at 4.8 million m 3 per year, of which 2.7 Mm 3 is surface water and 2.1 Mm 3 is groundwater [12][13][14]. The northern basins in Tunisia provide the largest contribution of surface water resources of the country.…”

“…By 2030, demand is likely to exceed the conventional resources available. It is expected that climate change will result in a significant reduction in rainfall and an increase in the frequency of droughts [12]. However, the extent and the accuracy remain imprecise.…”