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E. Iwasaki et al.
and salinity. The insufficient drainage is a second cause. Third causes are irrigation systems. Even arising from over irrigation is the depletion of groundwater quality. In addition, groundwater overpumping is a major contributor to
waterlogging development in Dakhla Basin.
27. The oases in Dakhla all display slight differences in the waterlogged area,
salinity and water quality. In these oases, however, the cultivated area can be
extended. The main problem with expanding the oasis may not be the amount
of water, because if there is sufficient money available for high-tech wells, a
large amount of water can be pumped out of NSAS. But a good management
must be implemented again in order to use the extracted water sustainably and
prevent waterlogged areas.
28. The groundwater aquifer is considered as the only natural resource for freshwater supply supplies in this area. However, it suffers from water table depletion
due to over exploitation and un-managed withdrawal.
29. Fresh groundwater of the shallow aquifer was dominated in the northern parts
and found to be located along the fault planes, which were probably connected to
the underlying sandstone aquifers (the Sabaya and Six Hills) with high permeability. The groundwater salinization is enhanced southward because of the
decrease in sand content, increase in shale with gypsum and evaporate bands in
the aquifer, and the decrease in aquifer transmissivity, which increase the salt
leaching by reducing the speed of groundwater flow.
30. Inspection of the obtained geophysical results and correlation with the available
geological, and hydrogeologic information revealed that the studied zone is
composed of successive layers of graded sand intercalated with thin clay layers
and the area is affected by several fault elements striking in different directions
and controlling groundwater flow and accumulation. Resistivity distribution
maps indicate that groundwater might be of good quality in the northern parts
than the central and southern parts.
4 Recommendations
The following recommendations are mainly extracted from the chapters presented
in this volume:
1. Stabilization of moving sand dunes in Dakhla Oasis is very difficult and expensive. Thus, the best way to overcome threatening dunes is to move away of
their path, and the new reclamation land should be in between the dune belts.
Laser stations are required to monitor the movement of sand dunes in Dakhla
depression.
2. It is recommended to study in detail the Duwi Formation as an extension of the
Phosphate bearing rock unit in Abu Tartur Phosphate Mining Project in Kharga
Oasis.
3. The importance of analyzing the landscape and landforms from a more wider
view by comparison with the other geographic regions surrounding Dakhla
E. Iwasaki et al.
and salinity. The insufficient drainage is a second cause. Third causes are irrigation systems. Even arising from over irrigation is the depletion of groundwater quality. In addition, groundwater overpumping is a major contributor to
waterlogging development in Dakhla Basin.
27. The oases in Dakhla all display slight differences in the waterlogged area,
salinity and water quality. In these oases, however, the cultivated area can be
extended. The main problem with expanding the oasis may not be the amount
of water, because if there is sufficient money available for high-tech wells, a
large amount of water can be pumped out of NSAS. But a good management
must be implemented again in order to use the extracted water sustainably and
prevent waterlogged areas.
28. The groundwater aquifer is considered as the only natural resource for freshwater supply supplies in this area. However, it suffers from water table depletion
due to over exploitation and un-managed withdrawal.
29. Fresh groundwater of the shallow aquifer was dominated in the northern parts
and found to be located along the fault planes, which were probably connected to
the underlying sandstone aquifers (the Sabaya and Six Hills) with high permeability. The groundwater salinization is enhanced southward because of the
decrease in sand content, increase in shale with gypsum and evaporate bands in
the aquifer, and the decrease in aquifer transmissivity, which increase the salt
leaching by reducing the speed of groundwater flow.
30. Inspection of the obtained geophysical results and correlation with the available
geological, and hydrogeologic information revealed that the studied zone is
composed of successive layers of graded sand intercalated with thin clay layers
and the area is affected by several fault elements striking in different directions
and controlling groundwater flow and accumulation. Resistivity distribution
maps indicate that groundwater might be of good quality in the northern parts
than the central and southern parts.
4 Recommendations
The following recommendations are mainly extracted from the chapters presented
in this volume:
1. Stabilization of moving sand dunes in Dakhla Oasis is very difficult and expensive. Thus, the best way to overcome threatening dunes is to move away of
their path, and the new reclamation land should be in between the dune belts.
Laser stations are required to monitor the movement of sand dunes in Dakhla
depression.
2. It is recommended to study in detail the Duwi Formation as an extension of the
Phosphate bearing rock unit in Abu Tartur Phosphate Mining Project in Kharga
Oasis.
3. The importance of analyzing the landscape and landforms from a more wider
view by comparison with the other geographic regions surrounding Dakhla