1.1.1.WATER RESOURCES There are four main river basins in Brunei Darussalam: Temburong, Belait, Tutong and Brunei. The Temburong, the smallest of the rivers, drains a catchment area of about 430km2. The Belait is the largest basin, with an area of 2,700km2. The lower catchment comprises an extensive area of peat swamp forest. The river narrows at the town of Kuala Belait and a sandbar restricts the discharge of water to the South China Sea. Some areas in the upper catchment have been cleared for agriculture. The Tutong basin, which is about 1,300km2 in area, has a complex estuary system formed between two sand spits. Subject to fairly high tidal influence, its lower catchment is mainly floodplain. The upper catchment is jungle with patches of agriculture. The basin also encompasses Brunei’s largest lake, the Tasek Merimbun. The Brunei river flows into Brunei Bay. The upper reaches of the river are a major fresh water source, particularly for the western part of the country. By analogy with the whole island, the runoff coefficient is estimated at 1.5m/year corresponding to a surface flow of 8.5km3. Limited reserves of groundwater have been identified in the Liang and Seria areas of the Belait district and in the Berakas area of the Brunei-Muara district. The estimated safe yield is 17.3 million m3/year. Also by analogy with the whole island, the total groundwater resources are estimated at 0.1km3/year, all being drained by the rivers. Internal renewable water resources are estimated at 8.5km3. Brunei Darussalam has two dams with a total storage capacity of just over 45 million m3. The Tasek reservoir used for water supply has a total capacity of 13,000m3 and a catchment area of 2.8km2. The Benutan dam, an impounded reservoir used to regulate the Tutong river, has a total storage capacity of 45 million m3 and a catchment area of 28.6km2. There is no hydropower dam, though one suitable site has been located within the National Forest Reserve of Temburong. Despite adequate rainfall, developing and maintaining sufficient water resources is difficult. The low-lying coastal plains mean that river water is generally brackish for a considerable distance inland, and the catchments in the coastal zones are inadequate for any major supply scheme (WPRO, 2006). Groundwater is also difficult to exploit due to the impermeability of the underlying rock strata (WPRO, 2006). The majority of water resources are derived from the three main river basins, the Tutong, the Belait and the Temburong, which although generally adequate can be adversely affected by extended periods of dry weather, and the construction of dams and storage reservoirs is needed to ensure reliable supply during these dry periods (WPRO, 2006). The extraction of raw water from any water source for the purpose of treatment for drinking water supply must be approved by the Water Services Department under the provisions of the Water Supply Act (1968). Normal treatment of raw surface waters is by dosing with lime or chalk to adjust the pH followed by flocculation and sedimentation using alum, and where necessary by the addition of polymer to speed up coagulation. The water is then filtered through rapid sand filters, before secondary pH adjustment with lime and disinfection with chlorine. Where required, sodium aluminate is used for the removal of colour (WPRO, 2006). There are four main urban water supply systems. The Brunei-Muara-Tutong System provides a water supply for two thirds of the country’s population, using raw water extracted from the Tutong river through three treatment works. During periods of dry weather, additional water is sourced from the Benutan Silver Jubilee and Tasek Dams. The Temburong and Belait Coastal Systems supply water from their respective rivers and, in the case of the Belait river, a barrage has been provided to prevent contamination of the water source by seawater. The Labi System also serves the Belait District by extraction of raw water from the Rampayoh river. Almost the entire population is now served by a reticulated drinking water system with 24-hour continuous supply through pipelines that follow the road networks. The remainder, who are in remote or difficult-toaccess areas, are provided with drinking water through basic rural water supply systems (WPRO, 2006). However, Brunei Darussalam reported that in 2006 its estimated population of 350,000 was almost entirely urbanised (99.9 per cent), with all having access to improved drinking water through household connections (WPRO, 2006).

1.1.2.WATER USE In 1994, the total water withdrawal was estimated at 92 million m3. Urban water supply is entirely from surface water. The major use of water in industrial processes is for the liquefied natural gas industry, which abstracts and treats its own water from the Belait river. Other industrial uses are on a smaller scale, for timber/sawmills, dairy farms, soft-drink manufacture and workshops, which account for an estimated 25 per cent of overall water demand. Initially, groundwater abstraction was undertaken in the 1950s for use by the oil and gas industries. This has been replaced by surface water resources. Groundwater abstraction, which accounts for 0.5 per cent of the total water supply, is currently limited to the local bottled water industry. The chemical and physical qualities of natural raw water are highly dependent on the volume of water in the system from rainfall. Generally the water in the low-lying peat swamp area has low Country Overview - Brunei Darussalam turbidity, but is acidic, low in calcium and can be highly coloured (WPRO, 2006). The low population densities of the catchment areas mean that pollution is not yet considered a major threat to raw surface water supplies, and potential sources of pollution are controlled under the Water Supply Act (WPRO, 2006). There are currently no major industries within catchment areas, and the small amount of agriculture that is carried out is controlled by the Agriculture Department of the Ministry of Industry and Primary Resources. Agricultural runoff and domestic waste discharges are sufficiently low to be adequately diluted and dispersed by the rivers, and new developments within catchment areas are carefully controlled to ensure that they pose no threat to the water supply system. All solid wastes are collected and disposed of in landfills. At present, the only real threat to water supply systems comes from seawater intrusion into estuaries and the low-lying reaches of rivers, but this has been addressed by the construction of barrages (WPRO, 2006). Although there is collaboration and exchange of information between the Ministries of Health and Development regarding water quality analysis, there is no over-arching national committee established specifically for monitoring and surveillance. Such a committee would oversee the establishment of National Standards for Drinking Water Quality, establish Water Quality Management Programmes appropriate for each agency, and review and update legislation and strengthen authority to enforce compliance and actions. This committee would also facilitate enhanced collaboration between all agencies involved in water supply to improve information exchange (WPRO, 2006). There is also a need for sufficient numbers of trained staff to ensure that programmes are conducted efficiently and effectively, and for the provision of regular training or refresher courses appropriate to the tasks being carried out (WPRO, 2006).

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH Brunei Darussalam has excellent facilities for the treatment of drinking water at six government treatment plants situated throughout the country. In addition, Brunei Shell Petroleum (BSP) and Brunei Shell’s Liquefied Natural Gas (LNG) manage two other facilities privately. There are also bottled water factories using advanced technology to produce purified water. Monitoring of treated water at treatment plants, storage points and end-points is carried out daily by the Departments of Water Services and of Public Works, and by the Ministry of Development. In addition, the Department of Health Services also audits the quality of water at treatment plants and end-points. Brunei Darussalam was declared malaria-free by WHO in 1987. Seventeen new cases were reported in 2003 but they were all imported cases. Malaria vigilance activities continue to be maintained and implemented by the Department of Health Services. Water- and sanitation-related diseases such as diarrhoeal diseases, hepatitis, cholera and typhoid occur in Brunei Darussalam (WHO, 2004). Safe drinking water is available at the turn of the tap and is presently enjoyed by more than 90 per cent of the population. Total water usage for the period under review reached 66,157 million L, an increase of 66,157 million L. The Water Services Department, Public Works, is directly responsible for the supply of potable water and management of fresh water resources. It manages several water treatment plants with a total capacity of more than 195 million L/day and has a modern laboratory to make sure that the quality of treated water meets safe drinking standards (Johannesburg Summit, 2002). Communicable disease is no longer considered a major threat to the health of the population of Brunei Darussalam, and the revenue from the oil and gas industry allows the government to provide the nation with one of Asia’s best healthcare systems. This includes three major hospitals and numerous health clinics throughout the country. Malaria has been eradicated, cholera is virtually nonexistent, and waterborne diseases attributable to the drinking water system are rare (WPRO, 2006). Surveillance and reporting of disease outbreaks is the responsibility of the Disease Control Unit (DCU) of the Department of Public Health Services, which also carries out epidemiological investigations, research and analysis and produces recommendations and responses to outbreaks through its Communicable Disease Surveillance System. It is also responsible for developing health-related action plans, standards and guidelines (WPRO, 2006). Currently there are two main water quality monitoring programmes conducted by the Environmental Health Services (EHS) of the Ministry of Health and the Department of Water Services (DWS) of the Ministry of Development, which work closely together and exchange data and information (WPRO, 2006). The EHS conducts routine monitoring and surveillance of water quality and waste disposal to control and prevent environment-related diseases and health risks and maintain a safe and healthy environment. Samples collected by EHS from each of the four districts are sent to one of the Department of Laboratory Services’ 10 laboratories for analysis. Chemical analyses are carried out on raw and potable water for both government and non-government agencies, while the Microbiology Laboratory provides microbiological analysis of water samples (WPRO, 2006). The DWS is directly responsible for the management of water resources and the supply of drinking water. It operates and maintains water supply systems including intakes, treatment works, pumping stations, reservoirs and pipelines, and conducts routine chemical and microbiological testing of raw water inputs and monitors the quality of treated supply to consumers. The DWS is expanding its water supply systems to meet the increased demand for drinking water, through the protection of existing resources and the development of new resources. Water samples are sent to its Tasek laboratory, which performs all physical, chemical and microbiological testing. Each treatment plant also has its own laboratory, which conducts testing to ensure the correct operation of the plants and the quality of treated water. These laboratories also test raw water quality from reservoirs and surface waters used in the treatment plant (WPRO, 2006). The Pollution Control Unit of the Ministry of Health also conducts sampling through its local Health Inspectorate, and together with the DWS ensures that drinking water conforms to WHO Drinking Water Guidelines. The Ministry is also considering a national effluent discharge standard (WPRO, 2006). Country Overview - Brunei Darussalam The present quality requirements for public water supply in Brunei Darussalam follow the World Health Organization’s (WHO) Drinking Water Guidelines (1993). Both chemical and microbiological testing is conducted to ensure that water supply conforms to these values (WPRO, 2006