Geography and Population
Indonesia is a tropical archipelago country of more than 13,600 islands. The country extends over an area of about 1,904,570 square kilometer (km2). The major islands are Sumatra, Java, Nusa Tenggara, Kalimantan, Sulawesi, Maluku, and Irian Jaya. Most of the major islands have a mountain range running their whole length. The mountains are of volcanic origin and in some cases still active. The elevations of the islands range from 0 to 5,030 meters (m) above sea level. For administrative purposes the country is divided into 26 provinces. The capital is Jakarta.
The land area is about 1.81 million km2 with a coastline exceeding 84,000 kilometers (km). In 1995, the total cultivated area was estimated to be 35,579,000 hectares (ha). Of the cultivated area, 13,836,000 ha were under permanent crops such as rubber, coconut, coffee, cocoa, and palm oil. Annual crops such as paddy, maize, soybean, sugar cane, and tobacco were grown on 21,743,000 ha. Farmholdings in Indonesia are relatively small: 34% are less than 0.25 ha and a further 25% are between 0.25 and 0.5 ha.
In 1996, the total population was about 200 million inhabitants (63.6% rural), with a growth rate of 1.7%. The average population density was 105 inhabitants/km2. The population is unevenly distributed with about 60% living on the island of Java, which has an average population density of over 800 inhabitants/km2. Another 20% of the population lives on the island of Sumatra, with a population density of 77 inhabitants/km2. Agricultural crop production and livestock contribute approximately 18% of gross domestic product (GDP). The agriculture sector provides employment for 49% of the population.
Climate and Water Resources
There are two seasons, the dry season and the wet season. The dry season lasts from March to August and the wet season from September to March with the heaviest rainfall usually from November to February. The average annual rainfall for the major islands is presented below.
River Basins and Water Resources
|Annual average rainfall|
|Source: Adapted from Ministry of Public Works data (1993).|
The groundwater resources are estimated at 455 cubic kilometers per year (km3/year), although most (an estimated 90%) return as base flow to the rivers. The groundwater potential in Indonesia is, therefore, limited and can meet only part of the urban and rural needs for water supply, while providing irrigation water for very limited areas in the eastern part of Indonesia.In some places, overexploitation of groundwater has led to critical problems. In Jakarta, total groundwater abstraction in 1993 was 32.6 million cubic meters (m3). Groundwater abstraction has caused saline groundwater to reach about 10 km inland from the coastline and led to land subsidence at a rate of 2 to 34 centimeters per year (cm/yr) in east Jakarta.
Although water resources are abundant, the seasonal and spatial variation in the rainfall pattern and lack of adequate storage create competition and conflicts among users. The annual renewable water resources are estimated to be about 2,838 km3. Municipal and industrial wastewater is discharged virtually untreated into the waterways causing rapid deterioration in the quality of river water.
Lakes and Dams
Most of the lakes in Indonesia are of volcanic origin. Lake Toba is the largest volcanic lake in the world with an average surface area of 1,100 km2 and an average volume of 1,258 km3. In 1995, there were 82 dams. The large dam capacity was 15.83 km3. The gross theoretical hydropower potential in Indonesia is estimated at 3,388 gigawatts per year (GWh/yr). In 1991, the total installed power capacity was 2,061 megawatts (MW) and hydropower accounted for 16.27% of the electricity generated.
In 1990, water withdrawals were 69.24 km3 for agriculture, 4.73 km3 for domestic and municipal water supply and 0.38 km3 for industrial use (Figure 1). As the nation has started to implement development programs in order to meet the sharply increasing needs for irrigation, safe drinking water, industrial water, energy, etc., the demand on water resources has increased rapidly. It is estimated that between 1990 and 2020, the demand will increase by about 220%. More than 50% of all irrigation water is consumed in Java.
In 1990, 35% of the urban population and 33% of the rural population had access to water supply.
Irrigation and Drainage Development
The development of community irrigation systems started more than two thousand years ago. Modern irrigation systems were introduced in the middle of the nineteenth century. The first water resources development project which incorporated multi-sectorial water allocation was the Jatiluhur project in west Java. This project, proposed in 1948, is the largest in Indonesia. It allocates water for irrigation, hydropower, and domestic water supply to Jakarta.
In 1969, with the launching of the five year development plan called Repelita, the Government started a major program in irrigation development which included: rehabilitation of existing irrigation works; expansion of service areas in existing schemes; construction of new irrigation systems; upgrading of semi-technical irrigation systems to technical level; introduction of special maintenance to upgrade the physical infrastructure; implementation of efficient operation and maintenance (O&M) for launching sustainable O&M programs; a credit program; and strengthening of WUAs.
In the first twenty-five years of development, spanning five Repelitas (1969-1993), termed 'Pembangunan Jangka Panjang I' (PJP I), or first phase of long-term development, water resources policies were directed to support the development of different sectors with the primary emphasis being on agriculture. During PJP I, about 1.44 million ha were provided with new irrigation systems, whilst 3.36 million ha of existing irrigation systems were either rehabilitated or upgraded through special maintenance. The success of this development is demonstrated by the country having achieved food self-sufficiency, particularly in rice, since 1984. Another result of Indonesia's development was the reduction of poverty from 44% of the population (54 million people) in 1969 to 13% (26 million people) in 1993.
The country has now embarked on the second twenty-five-year development period (1994-2019), termed PJP II, which started in April 1993 with Repelita VI. Here the emphasis is on sustainable development and management of water resources. Water resources have now been elevated to a full sector level and policies are directed to promoting a more effective and efficient management of water resources in an integrated manner. Greater emphasis is placed on sustaining self-sufficiency in rice and on the O&M of water resources infrastructure. In addition, the Government is implementing a crash program in Repelita VI to improve 1.0 million ha of village irrigation systems and to develop a 600,000-ha rice estate by swamp reclamation in central Kalimantan.
The irrigation potential of the country is estimated at 10.86 million ha. In 1996, the total land area equipped for full or partial control irrigation was 4.43 million ha. In addition, there were 0.70 million ha of "simple" irrigation and 1.96 million ha of village managed schemes. It should be noted, however, that large discrepancies are observed among sources of information, leading to important uncertainties about the areas under irrigation. It was reported that, in 1995, 638 reservoirs, 10,770 weirs, 1,017 barrages, 1,192 pumping stations, and 6,792 intakes were used to supply water to an area of 4,600,000 ha. Moreover, in 1995, irrigation from groundwater reportedly covered an area of 44,209 ha, of which 36,784 ha were served by 834 units of deep tube-wells, 4,204 ha by 363 units of intermediate tube-wells and 14,807 ha by 471 units of shallow tube-wells. Of the cultivated land, 23.5% have some kind of water management.
In Indonesia, fields under water management are classed in four types: technical, semi-technical, simple, and village managed. Usually the first three types belong to the public works system.
- Technical systems: in 1996, they served an area of 3,328,016 ha. They are characterized by permanent canals, control structures, measuring devices, and government control of water distribution down to tertiary level.
- Semi-technical systems: in 1996, they served an area of 1,099,906 ha. They are characterized by permanent canals, few control or measuring devices, and government control of generally only the source and the main canal.
- Simple systems: in 1996, they served an area of 697,194 ha. They are characterized by few permanent control or distribution structures and may be managed by farmers.
- Village managed irrigation systems: in 1996, they served an area of 1,961,496 ha. These systems are developed and managed spontaneously by farmers.
In 1995, the total area of irrigation schemes serving areas of less than 500 ha was 2,175,019 ha; of which 854,214 ha were government managed and 1,320,805 ha were farmer managed.
|Distribution of water managed areas by type (1996)|
The main objective of irrigation development in Indonesia is to expand the cultivation of rice paddy, the staple food in Indonesia. The major crops cultivated under control irrigation are paddy and palawija (dry season crops, e.g. corn, soybean, etc.). In 1996, the total harvested wetland paddy area was 10.2 million ha, including irrigated and rainfed lowland. In 1994, the average yield for irrigated paddy in Java was 5.4 tonnes per hectare (t/ha) and Java contributed 60% of Indonesia's rice production. In 1992, the average cost of developing a surface irrigation scheme was US$3,645/ha while the average O&M cost of a surface irrigation system was US$8.4/ha/year.
Indonesia has an estimated 39.0 million ha of coastal and inland swamps. The extent of arable swampland has not been assessed in detail but is estimated to be 7.5 million ha. In 1996, the tidal and non-tidal swamp area used for irrigation (mainly for rice) was about 1.18 million ha. The table gives a summary of water managed areas by type.
The 1945 constitution declared national water and land resources to be controlled by the State and that they should be utilized in an equitable manner for the benefit of the people. The responsibilities for the development and management of water resources and irrigation schemes are specified in laws, presidential instructions, and government regulations. The most important are:
- Presidential Instruction No. 1 (1969), on the management of irrigation water and maintenance of irrigation networks;
- law on water resources development No. 11 (1974);
- government regulations on beneficiaries contribution for maintenance cost of water resources facilities No. 6 (1981),
- decree of the Minister of Mining and Energy concerning underground water resources management (1983).
Numerous institutions are presently involved in water resources management. Their tasks and responsibilities are clearly stated in national legislation:
- The Ministry of Public Works, with its Directorate General of Water Resources Development, is responsible for planning, design, construction, equipment, O&M, and guidance in water resources development.
- The Ministry of Forestry is responsible for catchment area development.
- The Ministry of Environment is responsible for environmental quality development and management.
- The Environmental Impact Management Agency is responsible for environmental impact control.
Trends in Water Management
The Ministry of Public Works through its Directorate General of Water Resources Development (DGWRD) has identified four main missions in water resources sector programming as part of Repelita VI (1994-999). They are:
- Maintenance of self-sufficiency in rice production to achieve long-term food security. Although Indonesia achieved self-sufficiency in rice production in 1984, demographic growth, land use changes, variations in rainfall, climatic changes, drought, flooding, drainage problems in low-lying areas and urbanization have resulted in rice shortages requiring the importing of rice and the building up of costly rice buffer stocks. The DGWRD directs its programming towards activities which support the continued increase in rice production to maintain self-sufficiency.
- Provision of water to meet increasing water supply demands. Rapid industrialization, increasing urbanization and the need to supply the nation's population with safe drinking water have necessitated the development and maintenance of adequate water sources and supplies of proper quality water in many regions of the country. Often, the water needs are at locations far away from good quality water sources, so requiring large capital investments for conveyance infrastructures. The water sources are continuously subjected to water quality degradation due to urban, industrial, and upper watershed pollution. The DGWRD directs its programming to develop sources of good quality water and supply to demand centers to meet the needs for water supply.
- Flood alleviation and river management. Many of Indonesia's agricultural and urban areas are located in the lowlands. The majority of rivers flood frequently due to the high intensity rainfall in the watersheds and influx of sediment, particularly in lowland areas. In addition, the river morphology and carrying capacities are continuously changing due to sediment problems, large variations in flow, and human encroachment. To protect investment and economic activity as well as to ensure the availability of surface water resources close to demand centers, the DGWRD direct its programming to continuously improve flood protection and drainage, through both structural and non-structural measures, and to manage water bodies such as ponds, lakes, and reservoirs.
- Water resources development, conservation, and management. The archipelago nature of the country, variations in rainfall, large fluctuations in river flows and lack of proper storage sites have hindered the nation's ability to meet the increasing water demands. The gradual degradation of upper watersheds, poor groundwater resources, increasing water quality problems in the lower reaches of the rivers, and the inefficient use of water require a greater focus on water resources, conservation and prevention. Thus, to ensure the continued availability of water resources, the DGWRD direct its programming towards steps to improve water resources availability through appropriate conservation and management measures.
The four missions directed by the DGWRD are being implemented through a number of major and support programs. The water resources sector now has two major subsectors:
- water resources development, with three major programs:
- water resources development and conservation,
- supply and management of water,
- management of rivers, lakes, and other water resources;
- irrigation with, two major programs:
- development and management of irrigation networks,
- development and management of swamp areas.
- Water profile of Indonesia, Food and Agriculture Organization.
- World Factbook: Indonesia, Central Intelligence Agency.
- ESCAP. 1995. Guidebook to water resources, use and management in Asia and the Pacific. Volume 1: Water resources and water use, p. 306. Water resources series No. 74.
- FAO. 1992. Action programme on water and sustainable agriculture development in Indonesia. Executive summary.
- Jezeph, D. 1992. National water policy, p. 41 p. FAO. Rome.
- Ministry of Public Works, Directorate General of Water Resources Development. 1993. Twenty-five years water resources development in Indonesia (1969-1993), p. 126.
- Ministry of Public Works, Directorate General of Water Resources Development. 1996. Program Pembangunan Pengairan t.A. 1997/1998 dan Mid Term Review Pelita VI.
- Ministry of Public Works, Directorate General of Water Resources Development. 1993. Recapitulasi Inventarisasi Daerah Irigasi Seluruh Indonesia.
- Ministry of Public Works, Directorate General of Water Resources Development. 1995. Proceeding Lokakarya Pengembangan dan Pengelolaan Terpadu Sumberdaya Air Jabotabek.
- Ministry of Public Works, Directorate General of Water Resources Development in association with Agency for Research and Development, Research Institute for Water Resources Development. 1995. Bendungan Besar di Indonesia.
- Ministry of Public Works. Directorate General of Water Resources Development. 1993. The study for formulation of irrigation development program in the Republic of Indonesia. Nippon Koei Co., Ltd.
- Soenarno, I. 1995. Irrigation management transfer in Indonesia, p. 89-98. Paper presented at the conference on Irrigation Management Transfer in Asia held in Bangkok and Chiang Mai, 25-29 September 1995. International Irrigation Management Institute.
- Statistik Indonesia. 1996. Central bureau of statistics, statistical evaluation and report division, p. 588.
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