Drainage Principles and Applications IV. [antikvár]

PREFACE This book is the last of the four-volume series on Drainage Principles and Applications. The contents are based on lectures delivered in the International Course on Land Drainage, which is organized annually by the International Institute for Land Reclamation and Improvement. Since the decision of the Board of the Course in 1969 to have all lecture notes re-edited for publication by the Institute, the first three volumes have appeared. They were issued. 4972, 1973, and 1974, respectively. Volume I deals with introductory subjects," Vplume II with theories of field drainage and watershed runoff, and Volume III wft^. siifveys and investigations. Volume IV covers the design and management of dramage systems. As was mentioned in the Introduction to Vnluihe i, great efforts are made during the Course to cover the principles of land drainage. Within the three months that the Course lasts, it is impossible to cover every factor that may have a bearing on successful drainage. A choice has to be made, not only of the topics taught, but also on how thoroughly they are treated. Since the first course was held in 1962, constant attention has been given to its improvement. Scientific advances made it necessary to update some topics. New subjects were introduced and others were deleted or given less emphasis. Some subjects were split up into two or three new, ones and ?were-gone into more deeply. In many instances a subject has been presented by m'ofe th^n one lecturer during the 12 years that the course has been held; this also led to major and minor alterations in the original lecture notes. Some improvements were suggested by the participants themselves, who come from all over the world and have different educational backgrounds or are confronted with different types of drainage problems in their home countries. Nearly five years have passed since the contents of the four volumes and the titles of the various chapters were decided on. In this volume the reader will notice that some changes have been made in the hst of Subjects and Authors. Chapter 29 underwent substantial changes. Due to the death of one of its authors, Mr. G. Hekket, the revision of his part of the chapter was undertaken by Mr. M. G. Bos. who thus became co-author with Mr. J. A. van Dort. For editorial reasons Chapters 30 and 31 were interchanged. The chapter on maintenance of ditches with chemicals had to be updated and because its author Mr. H. G. van der Weij had retired, Mr. A. H. Druijff has written a new chapter on the subject. The title of Chapter 32 was altered to cover its subject matter more appropriately. Repeated requests from pardcipants led to the inclusion of three completely new subjects: Drainage of Heavy Clay Soils,