Boundaries seen and unseen - Resolving transboundary groundwater problems

International groundwater problems represent a distinct and important category of transboundary groundwater problems, but not all transboundary groundwaters are international. This paper considers transboundary groundwater problems in both intranational and international settings. First, difficulties attending the resolution of transboundary groundwater problems are identified, with intranational and international setting compared as general categories. Second, a set of intranational transboundary groundwater problems in the U.S. setting of southern California is compared with the analysis and recommendations that have emerged in the literature of recent decades on international transboundary groundwaters. The purpose of these comparisons of intranational with international transboundary groundwater problems is to more fully identify and understand what is, and is not, special about the challenges of resolving international groundwater problems. While international transboundary problems require the involvement (and in many instances the development) of different institutional arrangements, there are sound reasons to believe that in both international and intranational settings, the processes by which problem resolution is achieved may be more important than the content of the resolution.