Non-conventional water resources and opportunities for
water augmentation to achieve food security in
water scarce countries
Introduction
Looking at the natural global water cycle that yields an annual
renewable water supply of about 7000m3 per capita (Shiklomanov,
2000), it is evident that there is enough freshwater
available every year to fulfill theneeds of the presentpopulation
of this planet. However, in certain regions and countries the
annual renewable supply ofwater is less than500m3 per capita.
In addition, the availability of water varies greatly over time in
these areas, which results in extreme events. Floods and
droughts, forexample,occur frequently, sometimes in the same
area or neighboring regions. What this contrast illustrates is
thatmost of the freshwater available is concentrated in specific
regions, while other areas are water-deficient (Pimentel et al.,
1999; Rijsberman, 2006). Because freshwater resources and
populationdensities areunevenly distributedworldwide,water
demands already exceed supplies in regions that contain more
than 40% of the world’s population