Mahakam River

 

 Mahakam River

The Mahakam River is in Indonesia. It flows 980 km from the district of Long Apari in the highlands of Borneo, to its mouth at the Makassar Strait.

The city of Samarinda, the provincial capital of East Kalimantan, lies along the river 48 km (30 mi) from the river mouth.

Summary
The Mahakam River is the largest river in East Kalimantan, Indonesia, with a catchment area of approximately 77,100 km2. The catchment lies between 2˚N to 1˚S latitude and 113˚E to 118˚E longitude. The river originates in Cemaru from where it flows south-eastwards, meeting the River Kedang Pahu at the city of Muara Pahu. From there, the river flows eastward through the Mahakam lakes region, which is a flat tropical lowland area surrounded by peat land. Thirty shallow lakes are situated in this area, which are connected to the Mahakam through small channels. Downstream of the connection with the Semayang and Melintang lakes, the Mahakam meets three other main tributaries - the rivers Belayan, Kedang Kepala, and Kedang Rantau - and flows south-eastwards through the Mahakam delta distributaries, to the Makassar Strait.

Geology
Kalimantan, where the Mahakam lies, is part of the Sunda Continental Plate. The large island has mountain ranges between Indonesia and Malaysia, however, volcanism is absent in this island. As described by van Bemmelen (1949), River Mahakam rises in Cemaru (1,681 m) in the centre of Kalimantan, from there it cuts through the pre-tertiary axis of the island east of the Batuayan (1,652 m) and then reaches the tertiary basin of Kutai. Its middle course traverses a lowland plain with many marshy lakes. This intermontane depression is separated from the neighboring basin, the Barito depression, by a broad hilly tract of less than 500 m altitude. After this region, the Mahakam cuts through the Samarinda anticlinorium and reaches its alluvial delta, which spreads like a broad fan over the shelf-sea, with a base of 65 km and a radius of about 30 km.

Upstream of Long Iram (upstream part of Mahakam river basin) the river is flowing in tertiary rocks (Voss, 1983).Between Long Iram and Muara Kaman (middle Mahakam area) the river is flowing in quaternary alluvium, while in the downstream area between Muara Kaman and the coast including the Mahakam delta, tertiary rocks are again present. The presence of the large delta is explained by the formation and rejuvenation of the hilly region near Samarinda.

Climate
The Mahakam catchment is around the equator. According to Köppen climate classification, this area belongs to type Af (tropical rainforest) that has a minimum temperature ≥18 °C and precipitation of the driest month in normal year ≥60 mm Transfer of mass and energy in the tropical zone occurred through general air circulation known as the Hadley cell. According to Seidel et al. (2008) the precipitation pattern in this area is largely determined by this large-scale atmospheric wind patterns, which is observable in several ways throughout the atmosphere. This circulation carries moisture into the air, generating rainfall in equatorial regions, whereas at the edges of the tropical belt are drier. Within this circulation, evaporation occurs intensively around the equator on the centre of low pressure called the Intertropical Convergence Zone (ITCZ), characterized by accumulation of cloud in the area. The ITCZ moves following the pseudo-motion of the sun within 23.5°N and 23.5°S zone, therefore its position always changes according to this motion.

The ITCZ drives the Indo-Australian monsoon phenomena which influence the regional climate including the Mahakam catchment. In December, January, February (winter in northern hemisphere) the concentration of high pressure in Asia and low pressure in Australia make the west wind blows in Indonesia (west monsoon). In June, July, August concentration of low pressure in Asia (summer in northern hemisphere) and concentration of high pressure in Australia make the east wind blows in Indonesia (east monsoon). Due to the global air circulation and the regional climate mentioned above, the Mahakam catchment which is located around the equator has a bimodal rainfall pattern with two peaks of rainfall, which are generally occurred in December and May. This is because the ITCZ passed through the equator twice a year, from the northern hemisphere in September and from the southern hemisphere in March.

Lakes
There are about 76 lakes spread in the Mahakam river basin and about 30 lakes are located in the middle Mahakam area including the three main lakes (Lake Jempang 15,000 Ha; Lake Semayang 13,000 Ha; Lake Melintang 11,000 Ha). The lakes levels are seasonally fluctuated from 0.5 m – 1 m during dry period to seven meters during rainy season. The Mahakam lakes and surrounding wetlands act as water storage as well as a trap of sediment contained in the water flowing into the lakes which are now known to become shallower, presumably as a result of an imbalance between sediment input and slow subsidence.

Fishing is the primary source of livelihood in the Mahakam lakes area, most of the people around the lakes are fishermen. The middle Mahakam lake area is an area of intensive fishing activity with a productivity of 25,000 to 35,000 metric tons per year since 1970.

Delta
The Mahakam delta is a mixed fluvial-tidal dominated delta. The delta covers about 1800 km2, consisting of mangrove areas near the shore, Nypa swamps in the central areas, and lowland forest near the apex, corresponding to the first bifurcation, however, recent fishery development in this area has converted a vast area of mangrove into shrimp ponds (tambak). The delta has three main distributaries system directed Northeast, Southeast and South. The area between distributaries consists of a series of tidal channels generally unconnected to the main distributaries. The distributary channels are narrow and rectilinear with the depth ranging from 8 to 15 m and distributary channel bifurcations appear every 10 to 15 km.

This lower Mahakam area is the second most productive hydrocarbon basin of Indonesia which contains around 3 billion barrels of oil and 30 Tcf of gas reserves. Field geological investigations in this area was started in 1888 and in 1897 exploration drilling discovered oil at shallow depth of 46 m on the Louise structure. Production started in 1898 followed by expansion of exploration to the entire Mahakam.

Ecology
Mahakam and its floodplain is an ecologically important region. A total of 147 indigenous freshwater fish species had been identified from the Mahakam. The Mahakam hosts the freswater dolphin Irrawaddy Dolphin (Orcaella brevirostris; called Pesut by local people) a critically endangered fish species, which is included on CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) Appendix I. The Mahakam river basin is also an important breeding and resting place for 298 bird species, among them 70 protected and five endemic species: Borneo Dusky Mannikin (Lonchura fuscans), Borneo Whistler (Pachycephala hypoxantha), Bornean Peacock-pheasant (Polyplectron schleiermacheri), Bornean Blue-flycatcher (Cyornis superbus) and Bornean Bristlehead (Pityriasis gymnocephala).

A research cluster: "Upsetting the balance in the Mahakam Delta: past, present and future impacts of sea-level rise, climate change, upstream controls and human intervention on sediment and mangrove dynamics" extensively carry out research on the Mahakam. The cluster's objective is to study the impact of external forcing factors such as sea-level rise, climate change, upstream sediment, as well as human interference on past, present and future development of the Mahakam delta in different time scales.

Bridges
Bridges include the 400 m Mahakam Bridge and the 710 m Kutai Kartanegara Bridge. The latter collapsed on 2011-11-26.

Social aspect
The River Mahakam is an economic resource for fishermen and farmers, and as freshwater source, as a waterway since ancient time until today. It is in this river basin where the Kutai kingdom evolved. The Kutai history is divided into two periods, Kutai Martadipura (around 350-400) and Kutai Kartanegara period (around 1300). Kutai Martadipura, a Hindu kingdom founded by Mulawarman at Muara Kaman, is regarded as the oldest kingdom in Indonesia. Kutai Kartanegara was founded by settlers from Java at Kutai Lama near the mouth of Mahakam. In around 1565, Islam was extensively spread in Kartanegara by two Moslem preachers from Java, Tunggang Parangan and Ri Bandang.

The Dayaks are the indigenous people inhabiting Kalimantan beside the Kutais and the Banjars. Since the 1970s transmigration of people to East Kalimantan was organised by the Indonesian government especially in areas near River Mahakam. Transmigration aims to migrate people from overpopulated Java, Bali, and Madura islands to stimulate greater agricultural productivity in outer islands. By 1973, almost 26% of the land under cultivation in East Kalimantan was being worked by transmigrants.

Source: http://en.wikipedia.org

Credit Photo:  http://borneotourgigant.com

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Sabangau River

Sabangau River

The Sabangau River is a Blackwater river in Central Kalimantan, a province of Indonesia in Kalimantan, the Indonesian part of the island of Borneo. It flows through the Kelompok Hutan Kahayan or Sabangau peat swamp forest (5,300 km2), between the Katingan and Kahayan rivers. The peat swamp forest is a dual ecosystem, with diverse tropical trees standing on a 10m - 12m layer of peat - partly decayed and waterlogged plant material - which in turn covers relatively infertile soil.
Orang Utan in Sabah, Borneo

The forest is home to the world’s largest Orang Utan population, estimated at 6,910 individuals in 2003, and other rare or unique species. The total Agile Gibbon population in the Sabangau catchment is estimated to be in the tens of thousands, but is declining fast.

The forest has been damaged by legal and illegal forestry. There is no longer any continuous forest cover where Orang Utans may cross the river. A satellite view shows a grid of logging roads throughout most of the forest. However, the western part is now protected as either National Park or National Laboratory Research Area. A study of the area shows that the hydrological integrity of the forest has been maintained, and it is therefore ecologically resilient, although since it is close to the regional capital Palangkaraya it remains at risk.

Vulnerable bird species include the Large Green-pigeon (Treron capellei) and possibly Storm's Stork (Ciconia stormi) and Lesser Adjutant (Leptoptilus javanicus). Efforts are underway to establish long-term ecological monitoring in the forest.

The severely degraded eastern part of the forest, between the Sabangau and the Kayahan, is officially designated for agriculture. However, since the failure of the Mega Rice Project, which drained large areas of peat forest in an attempt to create rice paddies, no further efforts are being made to make it suitable for this purpose.

References

1. Density and population estimate of gibbons (Hylobates albibarbis) in the Sabangau catchment, Central Kalimantan, Indonesia
2. IMPLICATIONS OF GROUNDWATER LEVEL FLUCTUATIONS FOR A TROPICAL PEATLAND ECOSYSTEM IN SOUTHEAST ASIA
3. Birdlife.org Hutan Kahayan
4. The Orangutan Tropical Peatland Research Project:Monitoring ape populations in the Sabangau Forest, Central Kalimantan, Indonesia
5. THE IMPORTANCE OF ECOLOGICAL MONITORING FOR HABITAT MANAGEMENT - A CASE STUDY IN THE SABANGAU FOREST, CENTRAL KALIMANTAN, INDONESIA
6. orangutantrop.com: Sabangau Forest
7. Ecological Impact of the One Million Hectare Rice Project in Cantral Kalimantan, Indonesia, Using Remote Sensing and GIS. Boehm, H-D.V. and Siegert, F.

Source & Photo : http://en.wikipedia.org

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Ciberang River

The Ciberang River

A. Brief Information

The Ciberang River is one of tourism destinations, in Lebak District, Banten Province, that was officially launched for public visit on December 1st, 2007, by Hj. Ratu Atut Chosiyah,S.E., the governor of Banten Province. This 40 – 50 meters wide and around 1- 20 meters deep river flows from Halimun Mountain to Sunda Strait. People, who live around the Ciberang River, earn their living by taking advantages from the existence of the river. Likewise, the Ciberang River offers extremely challenging sport such as rafting, special for you who love extreme activities.

B. Distinctive Features

The Ciberang River offers the beauty of its surrounding nature. You will find the wonderful scenery of various trees, unique-shape rocks, green rice fields and plantations. The River flows approximately ten km, and challenges you, who love extreme sport such as rafting. You need about a half two hours to three hours to trace the river by rafting to observe the beauty of the river. Started from Muara Village, you will pass by Banjarsari Village, Lebakgendong Sub-district and Leui Bunjal Village, Cipanas Sub-district to reach the finish line of rafting. Various fields of rafting and barriers attract many visitors to try rafting in this River.

C. Location

The Ciberang River can be found in the Cipanas Village, Cipanas Sub-district, in the district of Lebak, Banten Province, Indonesia.

D. Access

To reach the destination, you may take public transportation from Bogor bus station passing through either Bogor – Jasinga or Bogor – Rangkasbitung routes. You need only to pay about IDR 10,000 to IDR 12,000 to reach the destination from Bogor City. You can also take private vehicles if you are from Jakarta by passing through Balaraja in approximately 100 km distance. Departing from Serang, you will pass by Rangkas Bitung in approximately 80 km distance to reach the location.

E. Ticket Price

There is no need to pay any entrance ticket to enter the location. However, you need to pay IDR 185.000/person to feel the unforgettable experience of rafting in the Ciberang River.

F. Accommodation and Other Facilities

Some supporting facilities have been provided for you there. Parking area, mosque, toilet, play ground, track rail and rafting equipments rental service are also available for you. Taste the typical food and beverage of Banten Province that can be easily found around the location. Likewise, assurance and water games are available for you who want to try to rafting in the Ciberang River. Bathrooms are also provided for you.


Credit Photo: http://images.google.co.id

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Musi River (Sumatra)

Location:
2°00'-2°30'S, 104°30'-105°15'E; the coastal area between the Sembilang River and Kuala Saleh, Sumatra Selatan Province, Sumatra.

Area:
150,000-200,000 ha of mangrove habitat.

Altitude:
0-0.5m.

Biogeographical Province:
4.21.12.

Wetland type:

06, 07 & 21. Musi River (Sumatra)

Description of site:
The very large delta system of the Banyuasin and Musi Rivers and numerous smaller rivers and mangrove creeks. The area comprises some of the most extensive mangrove forests in Sumatra, with intact transitions to freshwater and peat swamp forests. There are vast areas of intertidal mudflats along the coast, some of which are more than one km wide at lowest low tide. The area is under heavy pressure from reclamation activities, and a large part of the swamp forest has already been reclaimed. The peninsula between the Sembilang and Banyuasin Rivers is one of the most important areas for waterfowl in Indonesia, with thousands of large waterbirds and tens of thousands of migratory shorebirds. The many small villages built on poles on the coastal mudflats are very characteristic of this region. There are also a few larger coastal villages. The long term average coastal accretion rate is estimated at about lOOm per year. The soil consists of unripe clays (entisols) and peat; the clays often consist of potential acid sulphate soils. The tidal amplitude is about 2.0-2.5m.

Climatic conditions:
Humid tropical climate, with an average annual rainfall of 2,300 mm. The region is influenced by the northwest monsoon from November to February.

Principal vegetation:
Mangrove forests. More than 30 species of mangrove are known to occur; the main species are Rhizophora mucronata, R. apiculata, Avicennia alba, A. marina, Sonneratia alba, S. acida, Ceriops tagal, C. candoleana and Xylocarpus spp. There are also some extensive swamps of Nypa fruticans. Inland, the mangroves and nipa swamps give way to freshwater swamp forests, peat swamp forests and grassy marshes where the forest has been burned or logged.

Land tenure:
The wetlands are state owned (Government of Indonesia); surrounding areas are owned by the local authorities and local farmers.

Conservation measures taken:
None

Conservation measures proposed:
Silvius (1986) has proposed that the area between the Sembilang River and Banyuasin River (the Banyuasin Peninsula) be designated as a Nature Reserve. The administrative procedure to designate the area as reserve was initiated in late 1986. The reserve would cover an area of about 70,000 ha.

Land use:
Fisheries and small-scale logging of mangrove poles; fisheries and agriculture in surrounding areas.

Possible Changes in Land use:
Several areas have been proposed for transmigration projects, including part of the Banyuasin Peninsula. If these plans are carried out, most of the mangrove forest will be lost, including important breeding areas for the Milky Stork Mycteria cinerea and many other large waterbirds. Hardjowigeno and Situmorang (1987) have recently reviewed the impact of the transmigration programme on the mangrove ecosystem in the Banyuasin Musi Delta. Most of the freshwater swamp forests and peat swamp forests in the water catchment area have been or are being reclaimed or logged.

Disturbances and threats:
The major threats to the area are reclamation for official transmigration projects, reclamation by spontaneous transmigrants, logging of the mangrove forest, human disturbance at the breeding colonies of large waterbirds, and forest fires. The population of Estuarine Crocodiles Crocodylus porosus has already been almost exterminated by hunting.

Economic and social values:
The mangrove forest is extremely important for the local fishing industry which thrives largely on the shrimps and prawns which use the mangrove as nursery and breeding areas. The fishery industry is rapidly increasing in the area. The fishing villages are constructed mainly of timber taken from the mangrove forest and freshwater swamp forest. Tree species commonly used in the construction include Meranti (Shorea), Nibung (Oncosperma) and Bakau (Rhizophora). The mudflats may have a high potential for the cockle industry.

Fauna:
The mangrove forests are important breeding and nursery grounds for many species of marine fishes, prawns and shrimps. The area is one of the most important sites for waterfowl in Indonesia. Eighteen species of large waterbirds and 20 species of migratory shorebirds have been recorded. The area is presumed to contain the largest breeding colony of the Milky Stork Mycteria cinerea in the world. it is the only area in southeast Asia with a population of Spot-billed Pelicans Pelecanus philippensis; an immature observed in 1986 suggests that the birds are breeding in the area. It has the highest population of Lesser Adjutants Leptoptilos javanicus known in Indonesia. The endangered White-winged Wood-Duck Cairina scutulata occurs in the swamp forests behind the mangroves. The Grey Heron Ardea cinerea is known to breed in the area; the Great Egret Egretta alba probably breeds along with several other large waterbirds such as the Black-headed Ibis Threskiornis melanocephalus. Because of the difficulties of access, much of the area is still relatively untouched. A few fishermen collected some eggs and young of large waterbirds in 1982-1984, but the main breeding colonies of herons, egrets, storks and ibises have not as yet been located by biologists.The highest counts of large waterbirds obtained during surveys of the Banyuasin Peninsula in October 1984, July 1985 and March 1986 were as follows:
Pelecanus phhlippensis 9 Anhinga melanogaster 7
Egretta garzetta 48 E. sacra 12
E. intermedia 12 E. alba 2,414
Ardea cinerea 90 A. sumatrana 3
Mycteria cinerea 1,550 Leptoptilos javanicus 620
Threskiornis melanocephalus 607 Dendrocygna javanica 1,000

Counts of shorebirds on the Banyuasin Peninsula in October 1984, July 1985 and March 1986 gave totals of 37,900, 35,500 and 14,500, respectively. The highest numbers of each species recorded were as follows:
Pluvialis squatarola 100 P. dominica 6
Charadrius mongolus 9,460 C. leschenaultii 145
Limosa limosa 30,000 L. lapponica 7,000
Numenius phaeopus 700 N. arquata 1,965
N. madagascariensis 372 Tringa totanus 6,000
T. stagnatilis 100 T. nebularia 106
Xenus cinereus 3,500 Actitis hypoleucos 50
Arenaria inlerpres 500 Limnodromus semipalmatus 1,760-2,260
Calidris canulus 5 C. tenuirostris 66
C. ruficollis 100 C. ferruginea 700

Birds of prey recorded during the survey in July 1985 included 113 Haliastur indus, 12 Haliaeetus leucogaster and three Ichthyophaga ichthyaetus.

Mammals known to occur include Tiger, Leopard Cat, Common Otter, Wild Boar, Bearded Pig, Sambar, Long-tailed Macaque, Pig-tailed Macaque, Silvered Leaf Monkey and Otter-Civet (Panthera tigris, Felis bengalensis, Lutra luira, Sus scrofa, S. barbazus, Cervus unicolor, Macace fascicularis, M. nemestrina, Presbytis cristata and Cynogale bennettii).

The Estuarine Crocodile Crocodylus porosus is still present, although now in greatly reduced numbers as a result of intensive hunting pressure. The turtle Chitra indica is known to occur, and several other species such as Pelochelys bibronii may occur.
The delta is one of the richest areas for crustaceans in Indonesia.

Special floral values:
The mangrove forest is very rich in species. The freshwater swamp and peat swamp forests contain many commercially valuable tree species.

Research and facilities:
The vegetation has been surveyed by Sukristiyono Sukardjo and others (1979 & 1984), and several waterbird surveys have been carried out by ICBP and Interwader since 1983.

References:
Danielson & Skov (1986 & 1987); Hardjowigeno & Situmorang (1987); Karpowica (1985); Silvius (1986); Silvius et al. (1986); Sukardjo (1979); Sukardjo et al. (1984).

Criteria for Inclusion:
123.

Source:
Marcel J. Silvius.

Credit Photo: http://indonesia.sd

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