Low pressure buried pipe distribution systems for surface irrigation

Findings of research work into the use of buried pipe distribution systems for surface irrigation are detailed, based on a literature review, field evaluation of existing systems in south Asia and field work on existing buried pipe systems in Bangladesh. The extent and history of the use of buried pipe distribution systems is detailed in chapter two, along with trends in the upgrading and development of buried pipe systems. The comparative performance of buried pipe systems and open channel alternatives is discussed. Measurable benefits from buried pipe systems include reductions in seepage losses and a lower land take by the distribution system. Systems which are lower in cost than most lined channels are documented for some south Asian systems. Although low pressure pipe systems vary widely in design they can be classified as open, closed or semi-closed with regard to the method of pressure control, and as gravity or pumped supply with regard to the source of the driving head. These definitions along with consideration of the methods of regulating pipe distribution systems and the choice of the operating and control system, form part of the framework and classification for buried pipe systems presented in chapter three. Pipe systems in India, Bangladesh and Thailand, visited as part of the research work, are described and evaluated within the individual case studies set out in chapter four, along with summaries of the standard features of each of the pipe systems. [Continues.]