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Physical aspects and determination of evaporation in deserts applying remote sensing techniques
187
The second paper is by Rodier of ORSTOM and is in English and is virtually a summary of his experiences over many years of carrying out hydrological computations with inadequate data. The emphasis naturally is on tropical Africa. In summary the volume has the strengths and weaknesses of a collection of papers solicited for an international conference. They have been edited and presented to a high standard, but as a preconference publication do not reflect any of the discussion arising from presentation. The volume is not of outstanding value for the individual hydrologist or engineer but should certainly be acquired by libraries of institutions and consultants active in tropical hydrology. P.M. FLEMING CSIRO Division o f Water and Land Resources P.O. Box 16~6, Canberra City, A.C.T. 2601, Australia
EVAPORATION IN DESERTS APPLYING REMOTE SENSING
Physical Aspects and Determination of Evaporation in Deserts Applying Remote Sensing Techniques. M. Menenti. Rep. 10, Instituut voor Cultuurtechniek en Waterhuishouding, Wageningen, The Netherlands, 1984. 202 pp., Dfl. 45.00. Evaporation from deserts is often assumed to be nearly zero and the desert considered to be a homogeneous area of unchanging landscape. In this treatise which represents the author's dissertation, the reader is introduced to the complexities of the physical process in the desert environment. The author had four objectives in his study which focused on the evaluation of water resources and evaporation from deserts and in particular the evaporation from playas with shallow water tables. This book is not aimed toward the undergraduate student but rather the advanced scientist and engineer involved with water resource problems in semi-arid regions. The scope and treatment of the information could be extended to other semi-arid and arid ecosystems. The detail given by the author is sufficient for the reader to evaluate this approach with other data sets as well as evaluate the sensitivity of the technique in other geographical areas. At the end o f the book, there is a useful diagram which all readers should first refer to in order to grasp the complexity of the problem. There is a logic progression of scientific hypothesis building and testing throughout the book culminating in the evaluation of the method with satellite data. The reader, however, may be disappointed to find that the method is not truly driven only by remotely sensed data and that only a few days are examined. The author concludes from this study that to utilize satellite data for the estimation of evaporation the remote sensing data have
188
to be used in conjunction with ground based data. He also concludes that there is relatively low accuracy in the satellite data while the primary advantage lies in the large expanses which can be covered by a single image. This view may be somewhat limited, although probably correct for this area, because of the very small amount of actual satellitedata used in this study. The techniques proposed by the author will form the basis for many future studies on estimating evaporation from desert environments, and I believe that his treatment of the energy exchanges and evaluation of the possible flaws in the various approaches is among the best available at the present time. This treatise should be thoroughly studied by all individuals currently involved in evaporation research because of the views on all aspects of the energy balance and its application to evaluation of water resources. J.L. HATFIELD
ARS- U.S. Department o f Agriculture Route 3, Lubbock, TX 79401, U.S.A.
IRRIGATION
The Economics of Irrigation. Ian Carruthers and Colin Clark. Liverpool University Press, 1983. 300 pp., £10.50: ISBN 0-85323-464-7. This book represents an extensive revision and updating of Colin Clark's The Economics of Irrigation, the second edition of which was issued by Pergamon Press in 1970; it has been out of print since 1973. The new book examines the potential of irrigation in relation to rural development, emphasizing the principles relevant to the planning and operation of irrigation schemes and discussing their physical, biological, economic, financial and social implications. The book contains nine chapters. Chapters 1 to 3 are devoted mainly to technical aspects of irrigation practice. In this context, first the economics of irrigated agriculture is ldiscussed under the titles: Economic Concepts in Irrigation Practice, Planning Problems, Estimation of System Components, Factors in Irrigation Planning, Waterlogging, Quality of Irrigation Water and Salinity Problems, Agricultural Institutions and Irrigation Development, and Alternatives to Irrigation. In Chapters 2 and 3 the topics of water requirements of plants, crop response to irrigation, water resources and their exploitation problems are treated. Chapters 4 to 9 emphasise the principles relevant to planning irrigation investment and operation with a particular focus on ways of achieving economic efficiency. Main topics included are groundwater economics, costs of irrigation, economic returns, charges for water, and planning irrigation development.
The second paper is by Rodier of ORSTOM and is in English and is virtually a summary of his experiences over many years of carrying out hydrological computations with inadequate data. The emphasis naturally is on tropical Africa. In summary the volume has the strengths and weaknesses of a collection of papers solicited for an international conference. They have been edited and presented to a high standard, but as a preconference publication do not reflect any of the discussion arising from presentation. The volume is not of outstanding value for the individual hydrologist or engineer but should certainly be acquired by libraries of institutions and consultants active in tropical hydrology. P.M. FLEMING CSIRO Division o f Water and Land Resources P.O. Box 16~6, Canberra City, A.C.T. 2601, Australia
EVAPORATION IN DESERTS APPLYING REMOTE SENSING
Physical Aspects and Determination of Evaporation in Deserts Applying Remote Sensing Techniques. M. Menenti. Rep. 10, Instituut voor Cultuurtechniek en Waterhuishouding, Wageningen, The Netherlands, 1984. 202 pp., Dfl. 45.00. Evaporation from deserts is often assumed to be nearly zero and the desert considered to be a homogeneous area of unchanging landscape. In this treatise which represents the author's dissertation, the reader is introduced to the complexities of the physical process in the desert environment. The author had four objectives in his study which focused on the evaluation of water resources and evaporation from deserts and in particular the evaporation from playas with shallow water tables. This book is not aimed toward the undergraduate student but rather the advanced scientist and engineer involved with water resource problems in semi-arid regions. The scope and treatment of the information could be extended to other semi-arid and arid ecosystems. The detail given by the author is sufficient for the reader to evaluate this approach with other data sets as well as evaluate the sensitivity of the technique in other geographical areas. At the end o f the book, there is a useful diagram which all readers should first refer to in order to grasp the complexity of the problem. There is a logic progression of scientific hypothesis building and testing throughout the book culminating in the evaluation of the method with satellite data. The reader, however, may be disappointed to find that the method is not truly driven only by remotely sensed data and that only a few days are examined. The author concludes from this study that to utilize satellite data for the estimation of evaporation the remote sensing data have
188
to be used in conjunction with ground based data. He also concludes that there is relatively low accuracy in the satellite data while the primary advantage lies in the large expanses which can be covered by a single image. This view may be somewhat limited, although probably correct for this area, because of the very small amount of actual satellitedata used in this study. The techniques proposed by the author will form the basis for many future studies on estimating evaporation from desert environments, and I believe that his treatment of the energy exchanges and evaluation of the possible flaws in the various approaches is among the best available at the present time. This treatise should be thoroughly studied by all individuals currently involved in evaporation research because of the views on all aspects of the energy balance and its application to evaluation of water resources. J.L. HATFIELD
ARS- U.S. Department o f Agriculture Route 3, Lubbock, TX 79401, U.S.A.
IRRIGATION
The Economics of Irrigation. Ian Carruthers and Colin Clark. Liverpool University Press, 1983. 300 pp., £10.50: ISBN 0-85323-464-7. This book represents an extensive revision and updating of Colin Clark's The Economics of Irrigation, the second edition of which was issued by Pergamon Press in 1970; it has been out of print since 1973. The new book examines the potential of irrigation in relation to rural development, emphasizing the principles relevant to the planning and operation of irrigation schemes and discussing their physical, biological, economic, financial and social implications. The book contains nine chapters. Chapters 1 to 3 are devoted mainly to technical aspects of irrigation practice. In this context, first the economics of irrigated agriculture is ldiscussed under the titles: Economic Concepts in Irrigation Practice, Planning Problems, Estimation of System Components, Factors in Irrigation Planning, Waterlogging, Quality of Irrigation Water and Salinity Problems, Agricultural Institutions and Irrigation Development, and Alternatives to Irrigation. In Chapters 2 and 3 the topics of water requirements of plants, crop response to irrigation, water resources and their exploitation problems are treated. Chapters 4 to 9 emphasise the principles relevant to planning irrigation investment and operation with a particular focus on ways of achieving economic efficiency. Main topics included are groundwater economics, costs of irrigation, economic returns, charges for water, and planning irrigation development.