sufficient in many key areas. To this end, it is essential to couple chemical and biochemical phenomena with flow and transport processes. The kinetics of the reactions must be better controlled by the transport mechanism that brings the reactants into contact with one another. It is therefore essential to understand the exact coupling of flow and transport and the bio-geochemical mechanisms. Another theme strictly related to behavior in the unsaturated zone concerns flow and transport phenomena in the soil-plant-atmosphere system.
A new global approach is needed in order to achieve a better understanding of the behavior and evolution of the unsaturated zone and to develop suitable strategies for its optimal conservation, use and management.
5.4 Conflict resolution in water management
Water, an increasingly scarce resource, is already a source of conflict and likely to become even more so. In this context, scientists are faced with the challenge of developing suitable methodologies for emergency management and conflict resolution strategies. In this regard, simulation models linked with programming techniques for optimal management are crucial tools for proper planning and design of efficient and equitable integrated surface and groundwater use projects. Technology and expertise transfer from the scientific community to practitioners should be encouraged and enhanced. Decision makers also need to be able to recognize the potential of problem-solving measures, including emergency management and conflicts among different water uses and users. To this end, procedures for supporting negotiations for water allocation should be developed and tested for international, national or watershed