Action plan to avoid logjam recurrence in S'wak
Published: Nov 8, 2010 3:13 PM | Updated: Nov 8, 2010 5:16 PM
Sarawak will draw up a joint strategic action plan to avoid the recurrence of floating debris at Batang Baleh, Batang Rajang and Batang Igan in future.
Sarawak will draw up a joint strategic action plan to avoid the recurrence of floating debris at Batang Baleh, Batang Rajang and Batang Igan in future.
Second minister of planning and resource management Awang Tengah Ali Hasan said the preliminary investigation, conducted by government departments and agencies, represented an initial effort by the government to provide a better understanding of the cause and effect of the incident in early October this year.
"Following the preliminary report, all relevant government agencies have been directed to undertake a more comprehensive joint study to confirm the causes and impacts of the incident, and to draw up a joint strategic action plan," he said during the winding up speech for his ministry at the state assembly sitting in Kuching today.
The massive floating debris were sighted along Sungai Melatai, Batang Baleh, Batang Rahang and Batang Igan from Oct 5 to 10 and the entire length of the debris was estimated to be 20km, which was later separated into smaller sections further downstream of Batang Rajang.
Awang Tengah said the incident would not affect the government's commitment towards sustainable management of the natural resources of the state.
He said based on the preliminary reports, several factors were identified as contributing to the floating debris.
No extraction of timber detected
He said sustained heavy rainfall over a period of two weeks in the Melatai catchment area caused an over-saturation of the soil which caused numerous landslides over areas previously logged (for the last five years to 25 years) and over unlogged and primary forest areas.
"Consequently, huge masses of earth and debris as a result of landslides from these areas were washed down and blocked a section of Ulu Sungai Melatai (as was evident from the overflowed banks), forming a temporary barrier of debris "dam" estimated to be more than 20 meters high.
"When this impoundment broke, it unleashed a torrent of swift flowing water (flood wave), scouring the riverbanks of vegetation and other residues, causing the collapse of two bridges at Sungai Melatai.
"The water from other tributaries within Batang Baleh further aggravated the situation, causing a massive flow of
floating debris as was sighted downstream," he said.
He added that there was no extraction of timber detected within the affected area when the investigation was conducted.
On the impact of the unprecedented debris flow on aquatic life, Awang Tengah said it was likely to be for a short duration of time and only confined mainly upstream of the Melatai catchment due to high sedimentation.
"Its effects on aquatic habitat however were mitigated by the unaffected tributaries of Sungai Melatai, which provided refuge for the aquatic life during the duration of the debris flow and its immediate aftermath," he said.
Awang Tengah said the riverine traffic was also affected during the period of debris flow in the river and delays from one to five hours were reported as boat operators had to comply with precautionary safety measures prescribed by the Sarawak River Board.
Shallowness of river 'only temporary'
Meanwhile, Awang Tengah also said that the shallowness of the Sungai Balui on the upstream of the Bakun hydro-electric dam in Belaga due to the impoundment of the dam would only be temporary in nature.
He said the water level would rise when the water impoundment level reached the minimum operations level of 195 metres within a period of eight months and this would enable more water to be released from the Bakun dam.
"Such a situation would make it easier for the operations of the express boats," he said at the state assembly sitting.
Since the Bakun dam started the impoundment on Oct 13, the water level at several rivers including Sungai Balui and Rajang dropped drastically which resulted in the operations of express boats, which was the main mode of transport in the area, being affected.
On the safety aspects of the Bakun dam, Awang Tengah said his ministry had engaged an independent and reputable international consultant to undertake detailed review of the dam design and construction as part of its due-diligence exercise.
"The dam was designed and constructed to the latest international standards drawn from the past experience of both successful and failed dams.
"Multiple assessments of the seismicity of the project area have been carried out thoroughly. There is practically no major earthquake risk which might endanger the dam or the surrounding areas," he said.
The 2,400MW Bakun dam is expected to be fully operational by the end of 2012.
- Bernama
Second minister of planning and resource management Awang Tengah Ali Hasan said the preliminary investigation, conducted by government departments and agencies, represented an initial effort by the government to provide a better understanding of the cause and effect of the incident in early October this year.
"Following the preliminary report, all relevant government agencies have been directed to undertake a more comprehensive joint study to confirm the causes and impacts of the incident, and to draw up a joint strategic action plan," he said during the winding up speech for his ministry at the state assembly sitting in Kuching today.
The massive floating debris were sighted along Sungai Melatai, Batang Baleh, Batang Rahang and Batang Igan from Oct 5 to 10 and the entire length of the debris was estimated to be 20km, which was later separated into smaller sections further downstream of Batang Rajang.
Awang Tengah said the incident would not affect the government's commitment towards sustainable management of the natural resources of the state.
He said based on the preliminary reports, several factors were identified as contributing to the floating debris.
No extraction of timber detected
He said sustained heavy rainfall over a period of two weeks in the Melatai catchment area caused an over-saturation of the soil which caused numerous landslides over areas previously logged (for the last five years to 25 years) and over unlogged and primary forest areas.
"Consequently, huge masses of earth and debris as a result of landslides from these areas were washed down and blocked a section of Ulu Sungai Melatai (as was evident from the overflowed banks), forming a temporary barrier of debris "dam" estimated to be more than 20 meters high.
"When this impoundment broke, it unleashed a torrent of swift flowing water (flood wave), scouring the riverbanks of vegetation and other residues, causing the collapse of two bridges at Sungai Melatai.
"The water from other tributaries within Batang Baleh further aggravated the situation, causing a massive flow of
floating debris as was sighted downstream," he said.
He added that there was no extraction of timber detected within the affected area when the investigation was conducted.
On the impact of the unprecedented debris flow on aquatic life, Awang Tengah said it was likely to be for a short duration of time and only confined mainly upstream of the Melatai catchment due to high sedimentation.
"Its effects on aquatic habitat however were mitigated by the unaffected tributaries of Sungai Melatai, which provided refuge for the aquatic life during the duration of the debris flow and its immediate aftermath," he said.
Awang Tengah said the riverine traffic was also affected during the period of debris flow in the river and delays from one to five hours were reported as boat operators had to comply with precautionary safety measures prescribed by the Sarawak River Board.
Shallowness of river 'only temporary'
Meanwhile, Awang Tengah also said that the shallowness of the Sungai Balui on the upstream of the Bakun hydro-electric dam in Belaga due to the impoundment of the dam would only be temporary in nature.
He said the water level would rise when the water impoundment level reached the minimum operations level of 195 metres within a period of eight months and this would enable more water to be released from the Bakun dam.
"Such a situation would make it easier for the operations of the express boats," he said at the state assembly sitting.
Since the Bakun dam started the impoundment on Oct 13, the water level at several rivers including Sungai Balui and Rajang dropped drastically which resulted in the operations of express boats, which was the main mode of transport in the area, being affected.
On the safety aspects of the Bakun dam, Awang Tengah said his ministry had engaged an independent and reputable international consultant to undertake detailed review of the dam design and construction as part of its due-diligence exercise.
"The dam was designed and constructed to the latest international standards drawn from the past experience of both successful and failed dams.
"Multiple assessments of the seismicity of the project area have been carried out thoroughly. There is practically no major earthquake risk which might endanger the dam or the surrounding areas," he said.
The 2,400MW Bakun dam is expected to be fully operational by the end of 2012.
- Bernama
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