Jos Houterman, Mestika Djoeachir, Robiyanto Hendro Susanto, Frank van Steenbergen, on Agriculture and Rural Development Working Paper 14

Indonesia, a nation of 17,000 islands, is well known for its diversity. There are sensitive differences between the densely populated inner islands (Sumatra, Kalimantan, Sulawesi, Irian Jaya, and many others). The inner islands monopolize much of the economic and institutional power in the country. They contain 70 percent of the population. Java, the main island, with 813 inhabitants per km², is among the most densely populated parts of the world. In contrast, the national population density average is 93 persons per km². The lower density in the outer islands is mirrored in their different economies – with agriculture and resource extraction the major sector.

This report presents the findings of a literature review and field study on agricultural drainage in Indonesia. Indonesia was included as one of the six case studies as an example of drainage in the humid tropics. This kind of drainage is quantitatively different from land drainage in arid and semi-arid regions. Drainage in humid regions is not necessarily linked to irrigation. It is an intervention that, if done well, reclaims swamps, manipulates water table depths, allows the flushing of acids and toxicants, and facilitates the removal of stormwater.

Within Indonesia, there are large differences in drainage systems. The main distinction is between the inner islands and the outer islands, where water resources management reflects the differences in economic activity, population density, and topography in the densely populated inner islands and the resources-rich outer islands. The main theme of this study is the different contexts for water resources management and drainage. The study describes the development of drainage in Indonesia with special emphasis on lowland development, highlights Indonesia’s diversity, and present two different river basins – one from Central Java and one from South Sumatera. The main questions in the study concern the institutional arrangements for drainage and the contribution and place of drainage in integrated water resources management.