This book contains the lectures given in the International Course "Improving efficiency and reliability in water supply systems", hosted and sponsored by the Menendez Pelayo International University (U.I.M.P.) and co-sponsored by Aguas de Valencia, the British Council and the EC Cornett and Erasmus programmes. The short course took place in Valencia (Spain) in November 1994, with an attendance of more than one hundred delegates. We must not only acknowedge and thank Dr. Joaquin Azagra, as UIMP Director, but also his collaborators D. Luis Moreno and Lidia Lopez for their support in the...