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In the age of industrial development, lakes, rivers and canals have been exploited to an ever increasing extent, and dams and weirs for the diversion of river water have been constructed on flowing waterways for various purposes. Likewise, river intakes have been developed ever further for agriculture and the generation of hydroelectric power. Now, when in the industrialized countries, particularly in Europe, this development has practically come to an end - today there is only a very small number of sites for large-scale river water intakes - and in the developing countries the trend towards large-scale projects is, for a variety of reasons, decreasing, small-type projects are to the fore in the field of both energy production and agricultural irrigation.
The exploitation of rivers and streams requires thorough planning, irrespective of whether large-scale or small-scale projects are concerned. The ecological aspects, the compatibility of a project with the environment and the minimization of subsequent damage caused by any measure taken are important planning criteria. For large-scale projects, experienced planning engineers and experts are normally appointed. Micro-projects such as mills, small hydroelectric power plants, and small intake structures for irrigation purposes are often planned and constructed by the users themselves or by experts from other technical fields. Hydrologists and hydraulic engineers are frequently not consulted.
GATE has increasingly received enquiries from all over the world for planning fundamentals for intake structures of small-scale hydroelectric power plants, small irrigation perimeters and potable water intakes. Within the scope of the question-and-answer service, no comprehensive documentation on the planning of intake structures was available. The present work is intended to fill this gap. The authors realize that the relationship between water management and hydraulic engineering which forms the basis of the planning, i.e. the planning criteria, can only be touched on. These are intended to give the non-specialist working on the planning of intake structures some hints on the potential construction and to illustrate the complexity of the interrelationships. In just such small-scale projects as small river dams serious mistakes are often made which result in the destruction of the structures in a very short time during periods of flood. For this reason, an investigation into the discharge behaviour and regime of a flowing waterway from the point of view of water management is of decisive importance. Only in very few cases, however, can these hydrological investigations be carried out by nonspecialists. The methods and the necessary fundamentals are nevertheless given in this planning guide so that the non-specialist can at least see what data must be collected and what information must be made available to the planning engineer.
In addition to the individual types of intake structures, the necessary hydraulic and static calculation methods are given and explained in examples. This enables also the non-specialist to make at least a rough estimate of the dimensions of the structure and to form some idea of the costs involved. It is not the intention of this planning guide to enable non-specialists to plan and construct intake structures. The prerequisites to be met by the intake structure are different for each river and stream, and therefore only the basics can be described here. The operativeness of an installation depends largely upon the planning and, thus, upon the experience of the planning engineer. In just such a sensitive field as the intervention in a river or stream with a view to tapping water for general purposes, a great number of criteria are to be considered, and it is these which rare given in this planning guide.
The authors hope that this assistance will contribute to an understanding of the problems involved and in future help to avoid damage to intake structures.
The authors wish to thank the GATE members for their suggestions during the preparation of this planning guide and Professor Dr. H. Wittenberg for looking through the manuscript and giving valuable suggestions on additional information and the representation of the problems.
The authors also wish to thank Mrs. Mewes for the translation, and Mrs. Rubener for the editing.
Helmut Lauterjung
Gangolf
Schmidt
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