Despite the social, economic, environmental and political importance of groundwater, international law has paid relatively little attention to this resource. Groundwater represents about ninety-seven percent of the fresh water resources available, excluding the water locked in the polar ice. It serves the basic needs of more than one-half of the world's population and it is often the only source of water in arid and semi-arid countries. Improvements in pumping technology and growth in industry, agriculture, and global population are leading to ever increasing levels of use of this resource, and to growing reliance on it. Largely as a result of these phenomena, groundwater resources and the social, economic and environmental systems dependent on them have, over the last fifty years, come under pressure from over-abstraction and pollution, seriously threatening their sustainability.
International law has so far only rarely taken account of groundwater. While surface water treaties abound, groundwater is either nominally included in the scope of these instruments, mainly if it is "related" to surface waters, or it is not mentioned at all. Only few legal instruments contain groundwater-specific provisions, and even fewer address groundwater exclusively.
As groundwater quickly emerges from the limelight and gains strategic importance as a source of often high-quality freshwater in the face of the impending water crisis world-wide, the need for rules of international law addressing groundwater management and protection becomes ever more compelling. It is perhaps no coincidence that the United Nations International Law Commission (ILC) has the topic "Shared Natural Resources", comprising groundwater, oil and gas, in its programme of work. In addition, a trend can be detected to increasingly address groundwater in international agreements, non-binding instruments and interstate compacts, from a resource management as well as an environmental perspective.
It is against this backdrop that FAO and UNESCO have joined forces and embarked on this publication project. It brings together a variety of binding and non-binding international law instruments that, in varying degrees and from different angles, deal with groundwater. Its aim is to report developments in international law and to contribute to detecting law in-the-making in this important field.
The publication was prepared by FAO in connection with the UNESCO projects on international waters "Internationally Shared Aquifer Resources Management" (ISARM) and "From Potential Cooperation to Cooperation Potential" (PC-CP).
Stefano Burchi, Senior Legal Officer, and Kerstin Mechlem, Legal Officer, Development Law Service, FAO, are responsible for the scope and structure of the publication, for the selection of legal materials and their arrangement.