TROPICS Vol. 15 (3) Issued June 30, 2006 Inland water resources and limnology in Indonesia SULASTRI Research Center for Limnology, Indonesian Institute of Sciences, Cibinong, Bogor, Indonesia. Telephone: 6221−8757071; Facsimile; 6221−8757076; Email: [email protected] ABSTRACT Indonesia has a vast area of extent of inland waters in Indonesia, the have inland waters, consisting mainly of lakes, not been studied entirely. Many inland waters Reservoirs, rivers and swamps. There are have been researched, however data has not an estimated 14 million ha of inland waters, been compiled to allow to the construction consisting of 220 significant rivers, 50 big of an environmental information system, lakes and reservoirs, all over the country. which is crucial to balance development and The high population density and rapid conservation of inland water resources. development in all sectors has raised a lot of environmental issues, including those inland Key words: inland water, limnology, status, waters. The increasing demand for space, potential resources, problems, Indonesia. food, water and industrial products, forces Indonesia to its utilization of inland waters. The utilization of inland water resources INTRODUCTION creates some problems, such as water Indonesia is a vast archipelagic country with a total 2 pollution, siltation, eutrophication and the area of approximately 5 million km . It consist of more spreading of aquatic weeds and decreasing than 17,000 island, with a total line of 80,000 km. The 2 of indigenous species. Limnological on largest island is Kalimantan with an area of 547981 km Indonesia is still limited. Due to the large (Sugiharto and Poulin 1980 in Nontji, 1989). Table 1. Area, population density (1995) and population growth rate (1980−1995) of the main island of Indonesia (source: Statistical Yearbook of Indonesia, 1996). Island/ Area Population Population Population Province density Growth rate 2 −2 (km ) (%) (x 1000) (%) (km ) (%) Sumatra 482,363 24.90 32,763 20.96 85 2.57 Java & Madura 127,499 6.54 144,734 58.91 900 1.13 Bali 5,633 0.29 2,896 1.49 514 0.83 Nusa Tengggara Barat (NTB) 20,153 1.04 3,646 1.87 181 1.59 Nusa Tenggara Timur (NTT) 47,349 2.44 3,577 1.87 76 1.82 Timor Timur 14,606 0.75 840 0.43 57 2.35 Kalimantan 547,891 20.28 10,470 5.38 11 2.99 Sulawesi 191,800 9.90 13,732 7.05 72 2.18 Irian Jaya & Maluku 499,852 25.8 4,030 2.07 8 2.84 Total/average 1,937,179 100 194,755 100 101 1.9 Year 1997: estimated population 200 million; growth rate 1.7 %. 286 SULASTRI The inland water area is estimated Table 2. Area of open water in Indonesia (source: Directorate at 14 million ha, consisting mainly of General of Fisheries, 1981 in Nontji, 1989) Natural and man- Rivers, swamps, lakes, reservoirs and swamps. They Island Total (ha) made lakes (ha) peatland etc. have multifunctions: water supply, Sumatra 919,800 3,134,000 4,053,480 transportation, energy, fisheries and tourism. Indonesia is a big country with Java 23,780 72,590 96,730 population estimated of 194 ha in 1995 Kalimantan 637,410 8,391,530 9,028,940 and average population density of 101 Sulawesi 154,660 337,520 492,180 people km−2. The population however, Bali 2,450 460 2,910 is not evenly distributed; about 60% of Nusa Tenggara 2,680 11,860 14,540 total population lives in Java. On the Maluku & Irian Jaya 63,300 − 63,300 other hand in other islands like Irian Total 1,804,080 11,947,000 13,571,080 Jaya and Maluku, the population is still sparse with a density of only 8 people −2 Tabel 3. Number of lakes and reservoirs in Indonesia divided by km (Table 1). In Kalimantan, the area (source, Uchida,1997) population density is 11 people km−2 and 2 2 Lokacation Lake (km ) Reservoir (km ) the population is 10,470 million, or 5.38% >10 10< Total >2 2< Total of the total population. Compared to its Sumatra 7 11 18 (15.1%) 0 3 3 (7.7%) land area, Kalimantan has open spaces for development of many sectors such as Java 0 23 23 (19.3%) 23 10 33 (84.6%) industry, agriculture, or settlement, since Kalimantan 13 22 35 (29.4%) 1 0 1 (2.6%) Kalimantan is rich in natural resources Sulawesi 9 5 14 (11.8%) 0 0 0 (0.0%) and is fertile. Bali 1 3 4 (3.4%) 1 0 1 (2.6%) The increase of agriculture and Nusa Tenggara 0 0 0 (0.0%) 1 0 1 (2.6%) industrial development, as well a growing Irian Jaya 16 24 24 (20.2%) 0 0 0 (0.0%) urbanization, cause a lot of problems, East Timor 1 1 1 (0.8%) 0 0 0 (0.0%) especially for the environment. Problems Total 48 72 119 (100%) 25 13 39 (100%) for water includes eutrophication, siltation and pollution. Over-exploitation of inland water of inland water resources damages Uchida (1997) has compiled a list of several natural fisheries and decreases indigeneous species lakes and reservoirs from several references and maps. This paper aims to review inland water resources, He divided the water bodies into two categories: larger their use and associated problems and limnological than 10 km2 (major lake) and smaller than 10 km2. The research activities in Indonesia. same was also done for reservoirs: more than 2 km2 (major reservoir) and less than 2 km2 (Table 3). There are 119 lakes and 39 reservoirs in Indonesia mainly STATUS OF THE INLAND WATERS distributed in Kalimantan, Sumatera, Sulawesi and Java IN INDONESIA and Irian Jaya. The large-scale lakes are distributed in Lakes. Kalimantan and Irian Jaya, while lakes larger than 10 Since a great number of natural lakes are distributed km2 are not in Java. However approximately 65 % of the in Indonesia, many lake have not yet been inventoried reservoirs are in Java (Table 3). and completely investigated. Silvius et al. (1986) made a Some major lakes in Indonesia have been surveyed, preliminary inventory of exiting information on wetlands however many more are practically unknown, particularly (including lake) in Indonesia. In this inventory, 189 sites some major lakes in Irian Jaya. A list of major lakes are described with the aim of providing basic information and their surface area , maximum depth and elevation for developing nature conservation strategies. Lake is presented in Table 4. The largest lake is Lake Toba however, have not been included in it. The total area of (122,970 ha) in Sumatra, with a maximum depth of 450 Indonesian lake has been estimated by the Directorate m. The second largest is Lake Towuti (56,108 ha) in General of Fisheries (1981) in Nontji (1989) of 1.8 million Sulawesi. With a maximum depth of 203 m. While the ha (Table 2). deepest lake in Indonesia is Lake Matano (540 m), also in Inland Water Resources and Limnology in Indonesia 287 Tabel 4. The major lakes in Indonesia. Province Lake Max area Max Depth Elevation Type Source (ha) (m) (m) Aceh/Sumatra 1. Laut Tawar 7,000 80 1,100 Tectonic A North Sumatra 2. Toba 122,970 450 905 Tecto-vulcanic E West Sumatra 3. Maninjau 9,373 165 461.5 Tecto-vulcanic H 4. Singkarak 10,780 268 362 Tectonic E 5. Dibawah 1,200 80 800 Caldera E 6. Dibawah 1,200 44 1,531 Caldera E Jambi 7. Kerinci 5,200 110 783 Caldera E South Sumatra 8. Ranau 12,813 221 538.5 Tecto-vulcanic C West Kalimantan 9. Sentarum 80,000 8 35 Floodplain B East Kalimantan 10. Semayang 13,000 0.4−3.0 − Floodplain F 11. Jempang 15,000 − − Floodplain F 12. Melintang 10,000 0.4−3.0 − Floodplain F Central Kalimantan 13. Sembuluh 7,500 5 30 Low land B South Kalimantan 14. Panggang <1000 2.0−3.2 − Floodplain B 15. Sembujur <1000 1.8−2.4 − Floodplain B 16. Bangkau <1000 − − Floodplain B North Sulawesi 17. Tondano 5,000 20 600 − D 18. Limboto 5,600 2,5 25 − D Central Sulawesi 19. Poso 323,200 450 500 Tectonic D South Sulawesi 20. Lindu 3,200 100 1,000 Tectonic D 21. Matano 16,408 590 382 Tectonic D 22. Mahalona 2,440 73 310 Tectonic D 23. Towuti 56,108 203 293 Tectonic D 24. Tempe 35,000 2 5 Low land D Bali 25. Batur 1,590 88 1,031 Caldera E Irian jaya 27. Ayamaru 2,200 − − − 28. Anggi 2,000 − − − 29. Yamur 37,200 − − − 30. Tigi 3,000 − − − 31. Paniai 30,000 − 4000 − 32. Sentani 96,300 52 72 G Source: A: Saanin (1986); B: Silvius et al.(1986); C: Harsono &Wibowo (2002) D. Whiten E: Ruttner (1930); F: Lukman & Gunawan (1987). G: Sulastri & Sulawesty (1996). H: Sulastri et al, (2001). Sulawesi. The bottom of this lake is actually 208 m below small typical crater lakes found in around Lamongan sea level. Mountain, East Java. In Sulawesi, lakes are grouped into Most natural lakes were formed by volcanic or three major types: tectonic, volcanic and flood lakes. tectonic forces or a combination of both, or river action. Lake Tondano was formed as result of volcanic activity. In Sumatera, the majority of the lakes are volcanic. Mahalona, Matano and Poso were formed on flooded rift Lake Maninjau, Diatas, Dibawah, Kerinci and Ranau valley. Tempe, and Limboto are flood lakes. Most lake in are volcanic while Lake Laut Tawar and Singkarak Kalimantan were formed by river action.