H1-99, Social sciences (General), Social Sciences, Desalinización, sequía, HN1-995, Social history and conditions. Social problems. Social reform, History (General) and history of Europe, History (General), D1-2009, Latin America. Spanish America, F1201-3799, escasez de agua, trasvase, H1-99, Social sciences (General), Social Sciences, Desalinización, sequía...