Thursday, 7 June 2012
History of the singapore river:
From 1880s, there was an increase in the number of boats on the Singapore River due to urbanization and increase in trade. The sheltered harbour at the mouth of the river had facilitated trade and attracted people to Singapore. By 1970s, the river had become one large dumping ground for the street hawkers and squatters that had settled on its banks. Sewage and other waste from industries, such as farms, located along the river's banks also added to the pollution of the water along with, oil spills and wastewater from the many boats.
Currently, The Singapore River is approximately three kilometers long from its source at Kim Seng Bridge to its mouth at the Esplanade where it empties into the Marina Channel and finally the Singapore Strait; the waterway extends more than two kilometers beyond its original source at Kim Seng Bridge as Alexandra Canal, as far as the junction of Commonwealth Avenue. Here there is a break with Buona Vista Road where Sungei Ulu Pandan starts and flows into Sungei Pandan which in turn flows into the sea at West Coast Park. Thus, the source of both these waterways is in the Queenstown, Ridout Road Estate and Tanglin Halt area near Margaret drive.
Anderson Bridge to Kim Seng Bridge
Ways in which Singapore’s river had been altered and reasons for doing so:
Resettlements:
There was hardly any aquatic life as the river was so clogged up with rubbish before 1977. Thus, in 1977, the Ministry of the Environment drew up an action plan on the task of cleaning up the river and redeveloping the area around it. They resettled more than 16,000 families living in squatter colonies into public housing estates served by the public sewage system, waste storage and removal facilities, and the relocation of 2,800 polluting backyard industries to new industrial workshops in new industrial estates. About 5,000 street hawkers were relocated into food centres provided with public sewer and waste disposal facilities. 610 pig farms and 500 duck were either phased out or relocated to other areas. Polluting industries and trades were also shifted to other areas with proper pollution management facilities. In addition, sewer facilities were extended to the entire Singapore River and Kallang Basin catchment.
Singapore River as a dumping ground
Physical improvements:
After the source of pollution was removed, work was started to improve the physical appearance of the river. The river was dredged to remove tons of sediments deposited on the riverbed. Quay steps and walls along the river waterfront that had been deteriorated were repaired. The riverside walkway along the Singapore River were tiled, turfed and filled with bushes to add greenery to the riverside. Physical improvements to the beach along the Kallang Basin were also carried out. Facilities such as river walls, piers, shelters and benches were implemented to turn the surrounding area into a riverside park. Also, Clarke Quay was marked out as a commercial and entertainment zone, and Boat Quay was reserved for civil and commercial uses. After 10 years of cleanup, the project was finally completed in 1987.
Ensure sustainability of clean water:
Singapore continues to plan, coordinate and implement programmes to
prevent pollution from entering into the rivers. In addition,
Singapore launched the
Singapore Green Plan 2012 (SGP 2012) in 2002 to set down clear targets to enable
Singapore to strive for environmental sustainability.
Minimise chances of flooding and bank erosion:
River management has been carried out. Its main aspects are channelization, and dams like the Marina Barrage.
What is channelization?
Channelization of a stream may be undertaken for several reasons. One is to make a stream more suitable for navigation or for navigation by larger vessels with deep draughts. Another is to restrict water to a certain area of a stream's natural bottom lands so that the bulk of such lands can be made available for agriculture. A third reason is flood control, with the idea of giving a stream a sufficiently large and deep channel so that flooding beyond those limits will be minimal.
One major reason is to reduce natural erosion; as a natural waterway curves back and forth, it usually deposits sand and gravel on the inside of the corners where the water flows slowly, and cuts sand, gravel, subsoil, and precious topsoil from the outside corners where it flows rapidly due to a change in direction. Unlike sand and gravel, the topsoil that is eroded does not get deposited on the inside of the next corner of the river. It simply washes away.
Bank of Singapore River
Methods such as:
One method of reducing bank erosion is the construction of artificial barriers. This is a highly-effective short-term solution for developed countries which face a severe problem of bank erosion. The Singapore River has had artificial embankments constructed, creating a buffer between the banks and the river channel, greatly reducing bank erosion. This is especially important, as the areas around the Singapore River are heavily built-up. Bank collapse could destroy many buildings and incur large repair costs.
However, Despite their effectiveness at preventing erosion, artificial embankments must be regularly maintained to prevent cracks from forming in the structures. Also, such embankments are usually not appealing to the eye, and can reduce the recreational value of the river.
Another method is re-alignment. It is the straightening of the river channel. It is to remove meanders and reduces the length of the river channel. The straight channel increases the speed of the river to wash away accumulation of sediments along the river bed. Hence minimizing localized flooding. It also deepens the channel to allow it to hold more water, thus reducing occurrence of floods.
Dredging has been used to deepen and widen the river channel, increasing its capacity and allowing storm water to be discharged before the waters can reach flood height. However, this results in the loss of habitats for marine life. Because by shortening the course of rivers, the area of wetland shrinks because the river flows over a smaller land area now.
However,the rate of recovery for a stream once it has been dredged is extremely slow, with many streams showing no significant recovery 30 to 40 years after the date of channelization.
Channelization has several predictable and negative effects.
One of them is loss of wetlands. Wetlands are an excellent habitat for many forms of wildlife, and additionally serve as a "filter" for much of the world's surface fresh water. All animals play an important role in the eco-system. With the loss of wetlands, we reduce a part of our bio-diversity. Another is the fact that channelized streams are almost invariably straightened. This straightening causes the streams to flow more rapidly, which can, in some instances, vastly increase soil erosion. It can also increase flooding downstream from the channelized area, as larger volumes of water travelling more rapidly than normal can reach choke points over a shorter period of time than they otherwise would, with a net effect of flood control in one area coming at the expense of greatly aggravated flooding in another.
In addition, studies have shown that stream channelization results in declines of river fish populations. This loss of fish diversity and abundance is thought to occur because of reduction in habitat, elimination of riffles and pools, greater fluctuation of stream levels and water temperature, and shifting substrates. It is also an expensive method as resources such as manpower and funds are required to shorter the course of the river.
The Singapore River now flows into the Marina Reservoir after the damming of its mouth. This has created a valuable source of fresh water for Singapore. The dam is known as Marina Barrage.
The Marina Barrage is built across the Marina Channel. It creates the Marina Reservoir which is a freshwater lake and meets 10% of Singapore’s water demand. The Singapore River is one of the 5 rivers that flow into the Marina Reservoir. The Marina Reservoir will help provide a water supply and provide flood control.
To help provide flood control, the Marina Barrage will release the excess water into the sea. When is it low tide, crest gates will be open and the water will flow out. This is because the water level in the reservoir will be higher than the sea level. However, pumps have to be used to remove excess water during high tide as the sea level is higher than the water level in the reservoir. Each pump is able to empty an Olympic size swimming pool in a minute.
Marina Barrage
Singapore River vs Original state
A river in its original state will be very different. A river in its original state will have a very complex ecosystem and may have migratory fishes swimming between the river and sea. A dam such as the Marina Barrage will prevent fishes from swimming out of the river to sea and from the sea to the river. Much of the natural vegetation along the Singapore River has already been removed. This has negative effects on the ecosystem at the Singapore River and thus the biodiversity at the river has decreased significantly.
Pictures of us taken at our Project sites:
WE HAD LOTS OF FUN~
posted by Unknown at 22:06 || comment
Hope you had fun reading it! Thanks !
