The editors of this book would Uke to thank the company CESPA Ingenieria Urbana and the Institute of the Environment of the University of Girona for their financial support of the congress (7*^ Conference of the International Water and Resource Economics Consortium and 4^^ Seminar on Environmental and Resource Economics) that gave rise to a large number of papers collected in this book. We would also like to extend our thanks to Angels Xabadia who unified the layout of the different chapters in a timely and excellent manner. Finally our thanks go to the anonymous reviewers for their comments and.
