56
H.-J. Bolle
- 250 m (Lopez-Bermudez et al. 1999). The unsaturated layer increased by 200 m
and the drilling for water had considerably to be expanded.
For the Mediterranean countries not only the absolute amount of renewable
annual water resources is critical but the resources per capita which are presented
in Fig. 12. As can be seen, the future development of many areas of the region
becomes a matter of the relationship between the number of inhabitants and the
amount of renewable water resources. Angelakis and Kosmas (1999) point out that
by combining the projected renewable water resources with the projected population
development there may be dramatic decreases of the water resources per capita in
2050 by 50% in Algeria, Egypt, Israel, Morocco, and Tunisia. 60% reduction is
expected for Lebanon, 40% for Turkey, and 25% for Libya and Syria. Increases are
expected for Greece, Portugal, Italy, and Spain. Consequently the recycling of used
water and, maybe, the exchange of water resources becomes a major issue for the
future. The authors estimate that in Israel already 13% of the total water resources
is recycled.
Due to the rapid development of fresh water consume it is necessary to update
these data continuously. In the framework of the UNEP Mediterranean Action Plan
the Blue Plan Water Thematic Studies compiled detailed information about water
availability and consume in the Mediterranean countries (Margat and Vallee, 1999).
The WMO with the support of the World Bank established the Mediterranean
Hydrological Cycle Observing System (MED-HYCOS) as part of a global effort with
the goal to "contribute to the assessment of water resources and to their management
by helping national Hydrological Services to strengthen their capacities and by
promoting the exchange of information and skills among the countries participating
in the project" (MED-HYCOS/IRD, 1999). At a wider scope under the guidance of
the World Commission for Water in the 21 st Century the "World Water Vision" was
presented at the Second World Water Forum convened by the World Water Council
in The Hague, The Netherlands, in March 2000. The Global Water Partnership
prepared for this forum the basis for taking action which is documented under the
title: "Towards Water Security: A Framework for Action" (GWP, 2000).
6.3 Vegetation and Climate
Vegetation is an indicator ofland-surface processes and thus climate variability. The
vegetation cover depends strongly on the climatic environment, specifically its
hydrological properties, and it has a function in regulating the energy budget due to
albedo and stomata resistance effects. Otterman et al. (1990) furthermore claim
land-use change as a reason for precipitation change.
The from North to South decreasing vegetation cover is responsible for the
albedo gradient across the Mediterranean basin which keeps the surface net
radiation on both sides of the sea in narrow boundaries. In the South where the
albedo is high because the soil is bleached out over long times (the organic
component gets lost) a larger fraction of the solar energy is reflected and the
radiation budget is comparable with the values measured at the northern more
H.-J. Bolle
- 250 m (Lopez-Bermudez et al. 1999). The unsaturated layer increased by 200 m
and the drilling for water had considerably to be expanded.
For the Mediterranean countries not only the absolute amount of renewable
annual water resources is critical but the resources per capita which are presented
in Fig. 12. As can be seen, the future development of many areas of the region
becomes a matter of the relationship between the number of inhabitants and the
amount of renewable water resources. Angelakis and Kosmas (1999) point out that
by combining the projected renewable water resources with the projected population
development there may be dramatic decreases of the water resources per capita in
2050 by 50% in Algeria, Egypt, Israel, Morocco, and Tunisia. 60% reduction is
expected for Lebanon, 40% for Turkey, and 25% for Libya and Syria. Increases are
expected for Greece, Portugal, Italy, and Spain. Consequently the recycling of used
water and, maybe, the exchange of water resources becomes a major issue for the
future. The authors estimate that in Israel already 13% of the total water resources
is recycled.
Due to the rapid development of fresh water consume it is necessary to update
these data continuously. In the framework of the UNEP Mediterranean Action Plan
the Blue Plan Water Thematic Studies compiled detailed information about water
availability and consume in the Mediterranean countries (Margat and Vallee, 1999).
The WMO with the support of the World Bank established the Mediterranean
Hydrological Cycle Observing System (MED-HYCOS) as part of a global effort with
the goal to "contribute to the assessment of water resources and to their management
by helping national Hydrological Services to strengthen their capacities and by
promoting the exchange of information and skills among the countries participating
in the project" (MED-HYCOS/IRD, 1999). At a wider scope under the guidance of
the World Commission for Water in the 21 st Century the "World Water Vision" was
presented at the Second World Water Forum convened by the World Water Council
in The Hague, The Netherlands, in March 2000. The Global Water Partnership
prepared for this forum the basis for taking action which is documented under the
title: "Towards Water Security: A Framework for Action" (GWP, 2000).
6.3 Vegetation and Climate
Vegetation is an indicator ofland-surface processes and thus climate variability. The
vegetation cover depends strongly on the climatic environment, specifically its
hydrological properties, and it has a function in regulating the energy budget due to
albedo and stomata resistance effects. Otterman et al. (1990) furthermore claim
land-use change as a reason for precipitation change.
The from North to South decreasing vegetation cover is responsible for the
albedo gradient across the Mediterranean basin which keeps the surface net
radiation on both sides of the sea in narrow boundaries. In the South where the
albedo is high because the soil is bleached out over long times (the organic
component gets lost) a larger fraction of the solar energy is reflected and the
radiation budget is comparable with the values measured at the northern more