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Prospects for agricultural water management
Issues of water resources management will be increasingly important in the years ahead, especially in Java, which covers only 7 percent of the total area of the country, but has 59 percent of the population, 70 percent of irrigated agriculture, and 75 percent of the industry. Issues of water quantity include emerging conflicts between competing uses (agricultural, industrial and municipal), and between surface water and groundwater in rapidly growing urban areas. While Java is endowed with rainfall, it is highly seasonal. Dry season flows in the main rivers are only 20 percent of the annual flows. River basins on Java are relatively steep and short, and most of the wet season water runs unused into the sea. Reservoirs hold less than 5 percent of total river flows.
During the wet season, river flows bring high rates of sedimentation resulting from excessive erosion in the upstream part of the basin. This causes very fast sedimentation rates in reservoirs and lakes, making the lifetime of reservoirs shorter than planned, as well as reducing storage capacities. Most of the reservoircapacity of major river basins in Java (Bengawan Solo, Brantas, Citarum, Serayu-Bogowonto) was planned to meet the water demand for various uses up to 2010. While additional sites have been identified for future dams, implementation will be constrained by high population densities and the social and economic costs of resettlement.
Though industrial and municipal water use is still relatively low, it will increase over time. Meeting this demand will require a transfer of water in dry season from agriculture to municipal and industrial use. Minimizing the social and economic costs for farmers and potential disruption to agricultural output will require that water resources will be managed according to the integrated river basin principle. The challenge of meeting the water demand during the dry season is becoming even more complex if the pollution from growing urban and industrial waste is considered.
Based on the above conditions, an integrated action is needed to reverse the present trends of over-consumption, pollution, and increasing threat of drought and floods. To support water resources development and management, the government has proposed an Integrated Water Resources Management Policy framework to support and guide development and conservation effort. The policy is addressing water quantity and quality for both surface water and groundwater in the context of river basins, including the upper parts of the basins and estuarine areas. A specific component of the policy is dealing with environmentally and socially sensitive swampland development issues.
The future of irrigation should be considered as an integral framework to increase human welfare, to provide social justice, and to maintain ecosystem sustainability. Along with overcoming water and land resources problems, some national action should be taken, including: improving agricultural infrastructure, increasing the quality of intensification, improving the institutions, conducting reforestation and re-greening programmes.