3 Water Resource Availability and Quality …
37
a bias-corrected projection of increased rainfall is associated with increased ET in
the Nile Basin, and estimate the current climatology runoff (rainfall-ET) during the
period 1961–1990 at 155 km
3 /year for a basin area of 3,173,324 km
2 compared to the
current Nile flows of 84 km
3 /year measured at the High Aswan Dam (Egypt). Using
the same approach with unbiased corrected data sets, the projected wide-basin runoff
is estimated to be 83 km
3 /year by the year 2099 (a 24% decrease relative to the baseline) with nil contribution from the Main Nile, White Nile, and the Bahr Eljebel and
Bahr Alghazal sub-basins. In contrast, the Blue Nile sub-basin provides the highest
contribution, up by nearly 67%, followed by Lake Victoria (15%). Thus, the increased
ET would outweigh the increased rainfall. Regionalization of climate change impacts
on the hydrology of the Nile Basin requires sophisticated bias-corrected and observational datasets, which may change the projected runoff signal. The availability of
observational datasets is a real challenge considering the limited number of gauge
stations and the lack of regional data sharing measurement protocols so far. Nevertheless, the statistical bias correction approach could be successful (Nawaz et al.
2010).
4 Non-conventional Water Sources
This section provides an overview of water resource quality and its vulnerability to
climate change. It highlights current and future trends of the (re)use of unconventional
water resources, including desalinated water and wastewater.
4.1 Desalinated Water
Desalination of seawater and brackish water can be used to meet the increasing
demand for freshwater. Prospects for desalination vary greatly among the North
African countries, depending on their incomes and water scarcity. Algeria and Libya,
with high availability and low costs of energy, are likely to be the main drivers for
future seawater desalination. Current information indicates that desalination capacity
in the region is about 6.8 10
6 m
3 /day, largely contributed by Algeria at a rate of about
2.8 10
6 m
3 /day. For the time being, Morocco and Egypt have sufficient conventional water resources to satisfy most municipal needs. However, desalination tends
to be necessary for coping with serious shortages in some coastal areas, such as
the Egyptian Red Sea coast and Southern Morocco, with production capacities of
1.995 and 0.568 million
3 /day, respectively. Tunisia, with its limited energy and water
resources, has considered desalination to be a tool to bridge the gap between water
supply and demand within an integrated water resource management framework,
rather than a solution to solve water scarcity in the country. The capacity of desalination is estimated to be 200,000 m
3 /day. Figure 6 shows the distribution of the overall
desalination capacity among countries of the region.
37
a bias-corrected projection of increased rainfall is associated with increased ET in
the Nile Basin, and estimate the current climatology runoff (rainfall-ET) during the
period 1961–1990 at 155 km
3 /year for a basin area of 3,173,324 km
2 compared to the
current Nile flows of 84 km
3 /year measured at the High Aswan Dam (Egypt). Using
the same approach with unbiased corrected data sets, the projected wide-basin runoff
is estimated to be 83 km
3 /year by the year 2099 (a 24% decrease relative to the baseline) with nil contribution from the Main Nile, White Nile, and the Bahr Eljebel and
Bahr Alghazal sub-basins. In contrast, the Blue Nile sub-basin provides the highest
contribution, up by nearly 67%, followed by Lake Victoria (15%). Thus, the increased
ET would outweigh the increased rainfall. Regionalization of climate change impacts
on the hydrology of the Nile Basin requires sophisticated bias-corrected and observational datasets, which may change the projected runoff signal. The availability of
observational datasets is a real challenge considering the limited number of gauge
stations and the lack of regional data sharing measurement protocols so far. Nevertheless, the statistical bias correction approach could be successful (Nawaz et al.
2010).
4 Non-conventional Water Sources
This section provides an overview of water resource quality and its vulnerability to
climate change. It highlights current and future trends of the (re)use of unconventional
water resources, including desalinated water and wastewater.
4.1 Desalinated Water
Desalination of seawater and brackish water can be used to meet the increasing
demand for freshwater. Prospects for desalination vary greatly among the North
African countries, depending on their incomes and water scarcity. Algeria and Libya,
with high availability and low costs of energy, are likely to be the main drivers for
future seawater desalination. Current information indicates that desalination capacity
in the region is about 6.8 10
6 m
3 /day, largely contributed by Algeria at a rate of about
2.8 10
6 m
3 /day. For the time being, Morocco and Egypt have sufficient conventional water resources to satisfy most municipal needs. However, desalination tends
to be necessary for coping with serious shortages in some coastal areas, such as
the Egyptian Red Sea coast and Southern Morocco, with production capacities of
1.995 and 0.568 million
3 /day, respectively. Tunisia, with its limited energy and water
resources, has considered desalination to be a tool to bridge the gap between water
supply and demand within an integrated water resource management framework,
rather than a solution to solve water scarcity in the country. The capacity of desalination is estimated to be 200,000 m
3 /day. Figure 6 shows the distribution of the overall
desalination capacity among countries of the region.