CURRENT WATER RESOURCES CHALLENGES AND FUTURE PROSPECTS
Water, as a prime driver and determinant of human life, has been a principal factor for shaping human settlements across centuries. by Amine Salameh
Principal Engineer - Water at AECOM Middle East in Abu Dhabi (UAE) Introduction Water (or freshwater in particular) has been a principal factor and driver of human life, and has governed the locations of human settlements across centuries. London, Paris, New Orleans and Montreal are only a few examples of major cities that were located on a riverside for the use of freshwater resources, in addition to the transportation facilities that a river can provide. Such resources have been the subject of constraints and stresses from the quantity and quality viewpoints since the founding of cities or settlements; in addition, these resources are getting more prone to uncertainties with the passing of time. This article attempts to shed some light on the main challenges affecting the water
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resources and what might be expected in the near future in that respect, while acknowledging that this is a wide and massive subject of study that can sustain a lot of debate.
Background Water on Earth is available in abundance (1.39 billion km3 as total reserves, including oceans water). However, only 2.5% of this amount is freshwater and about two third of it is locked in the form of ice cap and glaciers at the poles (Shiklomanov, 1993). The FAO has estimated the global water resources in the order of 43,750 km3/year (FAO, 2000). The total freshwater withdrawals worldwide are 3,853 km3/year (FAO, 2010), i.e. about 9% of the global internal renewable water resources. A high percentage of these withdrawals is focussed on the agricultural sector (69%), while the municipal and
industrial parts amount to 12% and 19% on a global scale. The above are global numbers and different distributions for the agricultural and industrial sector percentages apply for specific regions and continents, depending on the historical background of each region in these two sectors. These region-specific numbers and percentages are shown in Table 1 opposite. It can be seen from the above table that the IRWR ratios are decreasing between years 2000 and 2020, because of the general increase in populations worldwide (except in limited areas such as Eastern Europe which experience population decline). However, the absolute values of the IRWR per inhabitant are not uniform across all regions. As such, it can be seen that the
