Coping with water scarcity requires that measures and policies of water management be in line with the challenging and widely accepted concept of sustainable development. This usually requires new approaches towards development and water and soil resources management. New perspectives are required for integrated management of the soil and water. This is not only a question of implementing new technologies and management approaches for allocating and controlling the water and land uses. Rather there is the need for also considering the driving forces governing the pressures on the resources themselves, the behaviour of the users, and the diverse human and social objectives. Despite the enormous progress in development of technological and managerial tools, which are
becoming available to improve management, there are still many gaps in knowledge and in development of skills for transferring scientific and technological knowledge into practice.
The concept of sustainable development is supported by a large number of definitions. The WCED (1987) introduced the concept as the "development which meets the needs of the present without compromising the ability of future generations to meet their own needs". A more specific definition: has been adopted by the WCED (1987):
"sustainable development is a process of change in which the exploitation of resources, the direction of investments, the orientation of technological development, and institutional change are all in harmony and enhance both current and future potential to meet human needs and aspirations".
This concept of sustainability relates to the human legacies that future generations will receive from the present. The legacy should enhance future prospects and opportunities and not restrict them in any way. As pointed out earlier, this is of great relevance for regions of water scarcity, where the cultural heritage relative to water has been threatened by the adoption of imported technological and management tools.
The FAO (1990) revised concepts proposed by many authors and formulated its own definition focusing on agriculture, forestry and fisheries: "sustainable development is the management and conservation of the natural resource base and the orientation of technological and institutional change in such a manner as to ensure the attainment and continued satisfaction of human needs for the present and future generations. Such sustainable development (in the agriculture, forestry and fisheries sectors) conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable". This definition fully agrees with that of WCED (1987), uses the same conceptual components and introduces the biodiversity implications.
Analysing definitions of sustainable agriculture, the NRC (1991), states that "virtually all of which incorporate the following characteristics: long-term maintenance of natural resources and agricultural productivity, minimal adverse environmental impacts, adequate economic return to farmers, optimal crop production with minimised chemical inputs, satisfaction of human needs for food and income, and provision for the social needs of farm families and communities".
Adopting the concept of sustainability, water management to cope with water scarcity has to:
be based on the knowledge of processes which can lead to resource degradation and to the conservation of natural resources;
include resource allocation to non productive uses such as natural ecosystems;
consider technological development not only for responding to production objectives but to control resource degradation and environmental impacts;
value the non-productive uses of the land and water;
prioritise processes which help reverse degradation;
include institutional solutions which support the enforcement of policies and rules and socially acceptable decisions and measures for land and water management;
rely on clear objectives focusing not only on the natural resources by themselves and
the economics of the returns from their use, but also embracing human needs and aspirations.
The sustainable development items enumerated early in this chapter were presented on the basis of the issues referred to above. Resource conservation and environmental friendliness are the main sustainability issues in relation to water and soil. Appropriate technologies constitute an essential challenge to achieve policies and practices well adapted for problem solving. The economic viability of measures to be implemented is a necessary condition for their adoption and a reason for provision of financial incentives. The need for appropriate institutional developments is considered as a pre-condition for implementation of innovative practices, whether of a technological, managerial, economic or social nature.
Finally, the social acceptability of measures to cope with water scarcity is particularly dependent on the development of awareness, within the local population, of water scarcity problems and the associated issues.
One potentially beneficial approach is to consider the water not only as a natural renewable resource but also as a social, environmental and economic “good”. Since scarcity favours assigning a high value to a good, valuing the water only as an economic, marketable good may provide only limited assistance in promoting sustainability. This is because water acts not only as the basis for production, but it also supports other natural resources and plays a major role in cultural and social contexts, particularly when scarcity gives it a special value. A coupled environmental, economic, and social approach is therefore required in valuing water in water scarce environments.