One of the major problem that related to land reclamation is subsidence. Subsidence, which refers to “the loss of surface elevation due to removal of subsurface support,” is caused by crustal deformation; sediment compaction; withdrawal of groundwater, hydrocarbons, geothermal fluids or minerals (sulphur); and dewatering of organic soils.
The sinking of the land is a process that varies throughout the reclaimed land. This is believed to result in part from geological processes like the compaction of relatively young sediments near the surface.
Initial subsidence takes place during the three years after reclamation, when approximately 50 percent of the thickness of the organic material above the groundwater will be lost. Pilings must be used to support foundations, driveways and other hard surfaces to prevent them from cracking and/or tilting.
Land subsidence normally occurs slowly, but the accumulation results in the crack of roads, the damage to pipelines and in the tilting or the cracking of the buildings.
With the relentless approval of high rise buildings on reclaimed land by Lim Guan Eng administration, the land subsidence problem can be further make worst by high rise buildings.
Induced sinkholes (catastrophic subsidence) are those caused, or accelerated, by human activities. These sinkholes commonly result from a water level decline due to pumpage. Construction activities in a cone of depression greatly increases the likelihood of sinkhole occurrence.
The rapid and deep excavation for multi-storey basements and foundations alone could displace thousands of cubic meters of ground water within a few months and could contribute in a large way to induced sinkhole.
With the uncontrolled withdrawal of underground water, the engineering environmental effect of the dense high rise buildings group will surely become the main cause of land subsidence.
It is difficult to monitor the subsidence caused by a large number of high rise buildings for a long time and the environment of the site changes greatly with time.
Induced sinkholes is already a major problem for Gurney Drive whenever a new high rise building is being built. You have witnessed the problem of induced sinkholes or the tilting of building in recent years.
A CASE of sinking land had put the brakes on a condominium construction project in Gurney Drive. After the gates and a stretch of road in front of the Gurney Park condominium sank 1.2m, the state’s municipal council ordered all construction work on the nearby Gurney Paragon condominium to be stopped. The council had ordered Hunza Properties, Gurney Park’s developer, to stop all work on the 43-storey project on Kelawei Road, near state capital Georgetown. The road next to Gurney Park’s multi-storey carpark was cordoned off after it sank and cracked. The cracks were estimated to be 1.2m deep and more than 9m long.
Do you realise the seriousness of induced sinkholes in Gurney Drive? It will be more worst and acute for Sri Tanjung Pinang if high rise buildings are allowed to be built on reclaimed land.
Without the ban of high rise buildings on reclaimed land, you can wait for disaster to happen in the unforeseen future.
Another problem associated with reclaimed land is coastal erosion. Man made reclaimed land is subject to erosion as it is against the nature hydraulic flow.
Water quality may be affected by erosion. Siltation of waterways can occur as a direct result of erosion of soil from the reclamation site. Stormwater should not be allowed to run through the reclamation site into nearby waterways and the sea without appropriate silt and erosion control measures being in place. There are several methods that can be used to manage the movement of water through reclamation sites. These include silt traps, retention of vegetation (buffer strips, grass) and construction of diversion walls or drains on the upstream side of the site to divert surface runoff towards appropriately controlled discharge points.
In addition, construction activities associated with reclamation may cause indirect siltation and sediment movement. For example, wharves and breakwaters can affect the hydrodynamics of the marine environment which may lead to erosion of adjacent foreshores and siltation of waterways. Excessive siltation may impact on local marine life (mangroves, molluscs, fish).
The first phase of the Sri Tanjung Pinang reclamation has witnessed the sedimentation and siltation of the whole of Gurney Drive and other areas.
The coastal erosion and the land subsidence are two major issues that Penang Forum has overlooked in reviewing the detailed EIA report of Sri Tanjung Pinang II. A proper DEIA should address both issues and provide the mitigation for both coastal erosion and land subsidence.
The detailed EIA need to address the following issues on Hazard Risk Management for land subsidence and coastal erosion:
a) Risk identification and assessment
What is hazard exposure?; What are economic and social losses?; Where is concentrated risk?
b) Risk mitigation
What structural and non structural methods can be used to mitigate physical damage?; what are intervention priorities considering risks to lives and need for emergency facilities?; How best can the be financed and sustained?
c) Emergency preparedness
Is the state government prepared to respond organizationally and technically to situation?; Functioning of existing conditions under stress?; How well are aid institutions integrated into emergency response systems?
d) Catastrophe risk financing
What is the state’s financial capacity to absorb catastrophic events?; How will funding gaps be addressed?
e) Institutional capacity building
What is the state's capacity to manage emergencies at different levels of government? Are both institutional framework and coordination mechanisms in place to allow for strategic decision making?
Consideration has to be given to the investment decision process to ensure technical social and economic consideration are incorporated
The state need to have a Hazard Risk Management Framework that address the following issues
1) Emergency preparedness
* Emergency response planning & exercises
* Public awareness
* Technical emergency response capacity
*Communication and information response management systems
2) Institutional capacity building
* Decentralized emergency management system
* Community participation
* Legislative framework
* Training education and knowledge sharing
* Inter governmental cooperation
3) Risk mitigation investments
* Warning and monitoring systems
* Hazard mapping and land use planning
*Hazard specific risk mitigation
4) Catastrophe risk financing
The state government need to commit itself on the following activities if it want to go ahead with land reclamation:
1) Development of coastal erosion risk mitigation strategy
2) Development of coastal erosion management plan
3) Need to implement land subsidence and coastal vulnerability assessments and associated hazard mapping
4) To identify areas which are particularly vulnerable to natural disasters as well as other impacts and assist in priority setting for corrective action
5) To provide coastal area assessments to assist in sustainable development of the reclaimed land coastline
6) Training/capacity building required in areas of vulnerability assessment, hazard mapping, oceanographic data interpretation and assessment
7) The ban of high rise buildings on reclaimed land
Only when you posed technical problems or tasks for the state government will it has trouble going ahead with land reclamation.
The sinking of the land is a process that varies throughout the reclaimed land. This is believed to result in part from geological processes like the compaction of relatively young sediments near the surface.
Initial subsidence takes place during the three years after reclamation, when approximately 50 percent of the thickness of the organic material above the groundwater will be lost. Pilings must be used to support foundations, driveways and other hard surfaces to prevent them from cracking and/or tilting.
Land subsidence normally occurs slowly, but the accumulation results in the crack of roads, the damage to pipelines and in the tilting or the cracking of the buildings.
With the relentless approval of high rise buildings on reclaimed land by Lim Guan Eng administration, the land subsidence problem can be further make worst by high rise buildings.
Induced sinkholes (catastrophic subsidence) are those caused, or accelerated, by human activities. These sinkholes commonly result from a water level decline due to pumpage. Construction activities in a cone of depression greatly increases the likelihood of sinkhole occurrence.
The rapid and deep excavation for multi-storey basements and foundations alone could displace thousands of cubic meters of ground water within a few months and could contribute in a large way to induced sinkhole.
With the uncontrolled withdrawal of underground water, the engineering environmental effect of the dense high rise buildings group will surely become the main cause of land subsidence.
It is difficult to monitor the subsidence caused by a large number of high rise buildings for a long time and the environment of the site changes greatly with time.
Induced sinkholes is already a major problem for Gurney Drive whenever a new high rise building is being built. You have witnessed the problem of induced sinkholes or the tilting of building in recent years.
A CASE of sinking land had put the brakes on a condominium construction project in Gurney Drive. After the gates and a stretch of road in front of the Gurney Park condominium sank 1.2m, the state’s municipal council ordered all construction work on the nearby Gurney Paragon condominium to be stopped. The council had ordered Hunza Properties, Gurney Park’s developer, to stop all work on the 43-storey project on Kelawei Road, near state capital Georgetown. The road next to Gurney Park’s multi-storey carpark was cordoned off after it sank and cracked. The cracks were estimated to be 1.2m deep and more than 9m long.
Do you realise the seriousness of induced sinkholes in Gurney Drive? It will be more worst and acute for Sri Tanjung Pinang if high rise buildings are allowed to be built on reclaimed land.
Without the ban of high rise buildings on reclaimed land, you can wait for disaster to happen in the unforeseen future.
Another problem associated with reclaimed land is coastal erosion. Man made reclaimed land is subject to erosion as it is against the nature hydraulic flow.
Water quality may be affected by erosion. Siltation of waterways can occur as a direct result of erosion of soil from the reclamation site. Stormwater should not be allowed to run through the reclamation site into nearby waterways and the sea without appropriate silt and erosion control measures being in place. There are several methods that can be used to manage the movement of water through reclamation sites. These include silt traps, retention of vegetation (buffer strips, grass) and construction of diversion walls or drains on the upstream side of the site to divert surface runoff towards appropriately controlled discharge points.
In addition, construction activities associated with reclamation may cause indirect siltation and sediment movement. For example, wharves and breakwaters can affect the hydrodynamics of the marine environment which may lead to erosion of adjacent foreshores and siltation of waterways. Excessive siltation may impact on local marine life (mangroves, molluscs, fish).
The first phase of the Sri Tanjung Pinang reclamation has witnessed the sedimentation and siltation of the whole of Gurney Drive and other areas.
The coastal erosion and the land subsidence are two major issues that Penang Forum has overlooked in reviewing the detailed EIA report of Sri Tanjung Pinang II. A proper DEIA should address both issues and provide the mitigation for both coastal erosion and land subsidence.
The detailed EIA need to address the following issues on Hazard Risk Management for land subsidence and coastal erosion:
a) Risk identification and assessment
What is hazard exposure?; What are economic and social losses?; Where is concentrated risk?
b) Risk mitigation
What structural and non structural methods can be used to mitigate physical damage?; what are intervention priorities considering risks to lives and need for emergency facilities?; How best can the be financed and sustained?
c) Emergency preparedness
Is the state government prepared to respond organizationally and technically to situation?; Functioning of existing conditions under stress?; How well are aid institutions integrated into emergency response systems?
d) Catastrophe risk financing
What is the state’s financial capacity to absorb catastrophic events?; How will funding gaps be addressed?
e) Institutional capacity building
What is the state's capacity to manage emergencies at different levels of government? Are both institutional framework and coordination mechanisms in place to allow for strategic decision making?
Consideration has to be given to the investment decision process to ensure technical social and economic consideration are incorporated
The state need to have a Hazard Risk Management Framework that address the following issues
1) Emergency preparedness
* Emergency response planning & exercises
* Public awareness
* Technical emergency response capacity
*Communication and information response management systems
2) Institutional capacity building
* Decentralized emergency management system
* Community participation
* Legislative framework
* Training education and knowledge sharing
* Inter governmental cooperation
3) Risk mitigation investments
* Warning and monitoring systems
* Hazard mapping and land use planning
*Hazard specific risk mitigation
4) Catastrophe risk financing
The state government need to commit itself on the following activities if it want to go ahead with land reclamation:
1) Development of coastal erosion risk mitigation strategy
2) Development of coastal erosion management plan
3) Need to implement land subsidence and coastal vulnerability assessments and associated hazard mapping
4) To identify areas which are particularly vulnerable to natural disasters as well as other impacts and assist in priority setting for corrective action
5) To provide coastal area assessments to assist in sustainable development of the reclaimed land coastline
6) Training/capacity building required in areas of vulnerability assessment, hazard mapping, oceanographic data interpretation and assessment
7) The ban of high rise buildings on reclaimed land
Only when you posed technical problems or tasks for the state government will it has trouble going ahead with land reclamation.
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