AGU will publish a Water Resources Monograph Series in 1971. The monographs are designed to present in depth the results of recent works of various authors in the fields of hydrology and water resources, stressing the application of techniques. They are meant to be an effective medium for disseminating current know-how in hydrology and water resources planning and management to those engaged in the day-to-day problems of water resources management. Although the Series stresses techniques and applications, the coverage of material is in sufficient depth to serve tutorial and state-of-the-art needs of students and researchers. In fundamental contrast with research papers, the monographs will limit discussion of unproven experimental work as well as complex and detailed mathematical manipulations. In general a strong emphasis will be placed on a thorough exposition of the techniques involved.