Blue, black and red rivers run through Jakarta

Bambang Nurbianto, The Jakarta Post, Jakarta

Jakarta is a city of rivers, as it has 13 main rivers and several tributaries. Unlike many foreign cities, however, where rivers are part of the beautiful cityscape and an asset to tourism, Jakarta's rivers are mere liabilities that cause many problems, including floods. Beginning with today's issue, The Jakarta Post is publishing a two-part story on the rivers of the capital. The first part covers their ecological conditions, while the second part will cover rehabilitation efforts by the government and the public.

Since the early days, Jakarta has been known as the city of rivers as dozens of rivers and canals -- small and large -- flow across the city. There are 13 main rivers in the city, most of which originate from the hilly areas in West Java.

In the past, Jakarta's rivers had at least three functions: flood control, water transportation and irrigation.

The last two are no longer relevant. An irrigation system is no longer needed as most rice fields have gone, while water transportation is a thing of the past for a variety of reasons, such as the rivers silting up and the presence of many other froms of transportation.

The rivers now solely function as flood control mechanisms, although they fail in this regard as they mostly cannot accommodate all the water during the rainy season. As a result, many areas of the city become inundated.

The rivers are also used as dumps, as both residents and businesses dump their liquid and solid waste there.

Consequently, nearly all rivers here are black and smelly, particularly during the dry season as the small volume of water cannot dilute the liquid waste.

Garbage and white suds are also commonly found in rivers during the season. Piles of garbage can easily be seen near bridges, floodgates and narrow sections, as the waterflow is unable to carry them downstream.

Despite such an appalling sight, neither officials nor citizens are ashamed; neither are they sufficiently motivated to do anything about cleaning up the rivers.

During the rainy season, water in the rivers turns yellow and the fast flow carries away a large amount of garbage. The majority of the rivers overflow and inundate roads and houses.

The main rivers flowing across the city mostly originate from hilly areas in West Java and flow to the capital through several autonomous regions like Bogor, Depok, Bekasi and Tangerang.

The City Public Works Agency groups the rivers into three categories, based on their location. In eastern Jakarta are the Cakung, Sunter, Jatikramat, Cipinang, Buaran and Kali Baru Timur rivers.

The annual floods caused by these overflowing rivers are usually worse than those caused by the others as the government has delayed construction of the Eastern Flood Canal (expected to accommodate excess flow from the rivers) due to financial difficulty, although it was designed in the early 1970s.

In the central part of Jakarta are the Ciliwung and Krukut rivers, while in the west, are the Angke, Mookervaart, Pasanggrahan, Kali Baru Barat and Grogol rivers.

One river or canal flows into another before all flow into the Jakarta Straits in North Jakarta.

Runoff from the Ciliwung, Krukut, Grogol, Pasanggrahan and Angke rivers is accommodated in the Western Flood Canal, which flows from Manggarai, South Jakarta, to Kapuk Muara, North Jakarta.

Other smaller rivers and canals include the Cengkareng Drain, Cakung Drain, the Cideng, Item, Sekretaris, Gresik, Besar, Ancol, Buntu, Tirem and Blencong rivers and the Angke canal.

Obstructed flow of water in the rivers during the rainy season causes many areas in the city still to suffer annual flooding. A total of 78 areas were affected by flooding, but this year the city administration could reduce this only by five, while the remainder will still be liable to flooding.

The Netherlands Engineering Consultants (NEDECO) survey, carried out after the latest floods, indicated a number of problems in the rivers, including sedimentation, intrusion by individuals and institutions, garbage, and other bottlenecks caused by bridges, clean water and electricity pipelines.

NEDECO also stated that the rivers and other flood control facilities experienced poor maintenance and operation over the past six years.

Sedimentation is a serious problem as it reduces the rivers' capacity to accommodate a huge amount of water during the rainy season.

Environmental damage caused by the widespread loss of forested and green areas to residential development in the Puncak and other upstream catchments has resulted in the high rate of sedimentation of rivers flowing to Jakarta.

Data on the erosion rate in the Puncak from the environment ministry shows that it reaches 400 tons per hectare per year -- far above the tolerable level of 39 tons. This may help to indicate how great is the sedimentation rate in the rivers, as many of them originate there.

Not included is sedimentation caused by widespread residential development in upper catchments like Depok and other areas in the southern part of the city.

That the rivers flow across several different autonomous administrations has made the problems more complicated. A common agreement is difficult to reach as each administration tries to defend its own interests.

The problems downstream are no less complex as they involve tens of thousands of people who now occupy riverbanks.

The government plans to build some 30,000 apartment units to resettle them. But it is unlikely that the projects can ever be realized in the near future, due to financial constraints.

Housing on riverbanks, some of which intrudes on rivers, causes two significant problems. First the presence of the buildings causes bottlenecks, and nearly everyone dumps their domestic waste in the rivers.

It is not easy to clear the riverbanks as the squatters have been there for a long time and argue that their presence is lawful, as most receive an electricity and clean water supply.