Water Sources In Brunei: A Daily Essential

People in Brunei get their water from four main river basins: Temburong, Belait, Tutong, and Brunei. Surface water supply, which makes up about 99% of water used for all purposes, comes from these river basins. The Brunei River, in particular, has been a major freshwater source for the western part of the country. Despite being used for transportation and waste disposal, it has remained relatively unaffected due to its self-purification capacity. However, high levels of water pollution in the river have been traced to wastewater treatment plants, industrial discharge, and polluted streams. To address water quality issues, the government has proposed various measures, including legislation to improve watershed protection and pollution management. Brunei also has six government treatment plants that maintain good drinking water quality, and bottled water factories that use advanced water technology to purify drinking water for the population.

Water sources

Brunei is a land of abundant water resources, with four main river basins providing surface water supply that accounts for 99% of water used in the country. These river basins – the Temburong, Belait, Tutong, and Brunei – are essential for both industrial and domestic water needs. The upper reaches of the Brunei River, in particular, serve as a significant freshwater source for the western region of Brunei.

The Temburong River, the smallest of the four basins, drains a catchment area of approximately 430 square kilometres. In contrast, the Belait River is the largest, with a catchment area of 2,700 square kilometres. The Tutong basin, with an area of about 1,300 square kilometres, features a complex estuary system formed by two sand spits. The Brunei River flows into Brunei Bay, providing a vital water source for the region.

While groundwater reserves are limited in Brunei, they have been identified in specific areas such as the Liang and Seria regions of the Belait district and the Berakas area of the Brunei-Muara district. The estimated safe yield from these groundwater sources is 17.3 million cubic metres per year. To ensure a reliable water supply during dry periods, the construction of dams and storage reservoirs is necessary, as extended dry weather can negatively impact the water levels in the river basins.

Brunei has two main dams, the Tasek reservoir, and the Benutan dam, with a combined storage capacity of over 45 million cubic metres. The Tasek reservoir, with a capacity of 13,000 cubic metres, is used for water supply, while the Benutan dam regulates the Tutong River and has a much larger storage capacity of 45 million cubic metres.

The majority of the population in Brunei, which is highly urbanised, relies on a reticulated drinking water system with continuous 24-hour supply through pipelines. This system is managed by the Water Services Department, which operates several water treatment plants with a total capacity exceeding 195 million litres per day. The department also conducts routine testing of raw water inputs and monitors the quality of treated water supplied to consumers.

Water treatment

Brunei is a small, highly industrialised country located in Southeast Asia. It has a tropical climate with high temperatures and rainfall. The country's water profile is dominated by the use of surface water, which provides over 99% of the water used for all purposes. This surface water comes from four major river basins: the Temburong, Belait, Tutong, and Brunei basins. The Belait River basin is the largest within Brunei.

The treatment of drinking water in Brunei is carried out by six government treatment plants located across the country. Additionally, two private water treatment plants are operated by Brunei Shell Petroleum (BSP) and Brunei Shell's Liquefied Natural Gas (LNG). Bottled water factories also utilise advanced water purification technology.

The normal treatment process for raw surface waters in Brunei involves the following steps:

• Dosing with lime or chalk to adjust the pH.
• Flocculation and sedimentation using alum, with the addition of a polymer to speed up coagulation if necessary.
• Rapid sand filtration.
• Secondary pH adjustment with lime.
• Disinfection with chlorine.
• Where required, sodium aluminate is used for colour removal.

Groundwater abstraction accounts for only 0.5% of the total water supply and is used by the local bottled water industry. The treatment of this groundwater can involve reverse osmosis, chemical dosing, and UV water sterilisation.

Brunei has two large dams that store the majority of the country's water. These dams help to prevent seawater intrusion and manage river flow. However, due to the low-lying coastal plains, river water is often brackish, and the catchments in the coastal zones are inadequate for major supply schemes.

To address water quality issues, the government has proposed upgrades to monitoring systems and quality management frameworks under the Tenth National Development Plan. Despite the current high levels of access to clean water, the government aims to maintain and improve water quality to meet the demands of a growing population and rapid industrial development.

Water supply

However, water quality in Brunei is a concern and could decrease in the future if no action is taken. High levels of water pollution in the Brunei River have been linked to wastewater treatment plants, industrial discharge, and polluted streams. Population density and urban catchment systems have been identified as the main reasons for the pollution. To address these issues, the government has proposed various measures, including introducing legislation to improve watershed protection and manage pollution.

Brunei also has limited reserves of groundwater, found in the Sungai Liang and Seria areas of the Belait district and in the Berakas area of the Brunei-Muara district. The estimated safe yield from these sources is 17.3 million m3/year. The majority of the population is served by a reticulated drinking water system with a 24-hour continuous supply. Six government treatment plants maintain good drinking water quality, and there are also private water treatment plants operated by oil and gas companies.

To ensure a reliable water supply during dry periods, the construction of dams and storage reservoirs is necessary. Brunei has two dams with a total storage capacity of just over 45 million m3. The Tasek reservoir is used for water supply and has a capacity of 13,000 m3, while the Benutan dam, an impounded reservoir, is used to regulate the Tutong River and has a storage capacity of 45 million m3.

In summary, while Brunei currently has sufficient water resources to meet the demands of its population, there are concerns about future water quality and supply. The government is taking steps to address these challenges through legislation, infrastructure development, and water treatment measures.

Water quality

The majority of Brunei's drinking water is sourced from river water. The four river basins of Daerah Tutong, Kuala Belait, and Temburong provide 99% of the water used for all purposes in the country. The Brunei River, in particular, has been a major freshwater source for the western part of the country. Despite being used for transportation and waste disposal, it has remained largely unaffected due to its natural capacity for self-purification.

However, high levels of water pollution in the Brunei River have been traced to wastewater treatment plants, industrial discharge, and polluted streams. Population density and urban catchment systems have been identified as the main reasons for the pollution in the rivers, especially the Brunei River. Point and non-point pollution sources, including residential, industrial, and agricultural outlets, are currently the primary sources of pollution. Domestic waste and surface runoff constitute about 50% and 29%, respectively, of the load discharged into the watercourses.

The government has recognised the need to address these issues and is considering introducing legislation to improve watershed protection and manage pollution. They have also proposed water conservation and sustainability measures, as well as upgrades to existing monitoring systems and quality management frameworks under the Tenth National Development Plan.

A study investigating the influence of climate change on water quality in Brunei found that changes in climate, such as decreased precipitation and increased rainfall intensity, correlated with changes in water quality, specifically a rise in aluminium concentrations. The study also found a correlation between low pH values and higher aluminium concentrations, which have been rising over time.

To maintain its high water quality, Brunei has six government treatment plants located across the country, ensuring good drinking water quality. Additionally, private water treatment plants are operated by Brunei Shell Petroleum (BSP) and Brunei Shell's Liquefied Natural Gas (LNG). Bottled water factories also utilise advanced water technology to purify drinking water for the local population.

Water pollution

Population density and urban catchment systems have been pinpointed as the primary reasons for the high levels of pollution in the country's rivers, particularly the Brunei River. As the population continues to grow and economic development progresses, the pressure on water resources increases, leading to a higher risk of water pollution. Industrialization and increased population are not only challenges for Brunei but for countries worldwide.

Domestic waste and surface runoff constitute a significant proportion of the load discharged into the rivers. The good news is that the rivers can dilute and disperse these pollutants due to their high flow rates. However, this does not negate the need for proper waste management and pollution control measures.

The government of Brunei has recognized the importance of addressing water pollution and is considering introducing legislation to improve watershed protection and pollution management. They are also investing in upgrades to monitoring systems and quality management frameworks under the Tenth National Development Plan. Additionally, water conservation and sustainability measures are being proposed to maintain the supply and distribution of clean water.

The impact of climate change on water quality in Brunei is also a growing concern. Studies have shown that changes in climate, such as decreased precipitation and increased rainfall intensity, can negatively affect water quality. For example, these changes have been correlated with rising aluminum concentrations in the water.

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