What is Surface water systems

Assessing the environmental and climatic impacts in the Nile Basin is imperative for appropriate decision and policy making on national and regional levels. Tracer techniques provide basic spatio-temporal tools for quantifying ongoing and past, and for predicting future, environmental and climatic impacts in whole Nile Basin. These tools allow the sustainable use of the natural resources through developing appropriate large-scale and long-term management and planning strategies. Radiotracers, for example, have diverse properties, unique sources and cycles in the environment. They provide powerful approaches to understand the behaviour of atmospheric processes, and the role of dry and wet-deposition on transfer of matter from the atmosphere to the earth’s surface. They are, also, useful for assessing the present status and evolution, as well as for quantifying the functioning and metabolism, in complex aquatic and land-water systems through appropriate definition of the spatio-temporal scales forcing their interactions with the environment and climate. They yield rich data on sources, pathways and flow-rates of matter (e.g. nutrients and pollutants) within and between landscape units and at the critical boundaries of the hydrosphere with the lithosphere, ecosphere and the atmosphere. Mitigation and adaptation strategies for coupled environment-climate policies require records and observations supported by model and forecasting infra-structures that can simulate the impacts of coupled environment-climate changes both on local and landscape scales. Impacts of global warming are not straightforward to predict unless reasonable scales can be used to compile and collate the diverse climatic and environmental data. Coordinated studies and observations of complex river-, lake-catchment, land-water and delta-coastal systems can provide a wide-range of information on human and climate impacts through using radiotracers as common time and space indicators for assessing the flow of matter on earth’s surface. In this context, the Nile Basin can serve as a model for coupled environment-climate impact studies in complex aquatic systems where sustainable management policies, e.g. use of natural resources, protection and rehabilitation, are needed.