Malaysia consists of two large land masses over 500 km apart, separated by the South China Sea. Peninsular Malaysia is a continuum of the Asia continent, a narrow land mass sandwiched by Thailand in the north and Singapore in the south.East Malaysia, comprising the states of Sabah, Sarawak and the Federal Territory of Labuan, is situated on the island of Borneo and is bordered Brunei and Kalimantan, Indonesia. The country occupies about 330,000 km2 of land area, of which 40% is the Peninsula and 60% East Malaysia. Because of their differing histories, geographic locations and physical features, Peninsular Malaysia and Borneo are significantly different in their biological holdings. Both areas are inhabited by many endemic species, while even shared species have distinct genetic differences. Malaysia's territorial waters cover an area of 549,500 km2. Its maritime borders with Indonesia, Singapore, Thailand, Brunei and Philippines. The principal water bodies are the Straits of Malacca and the South China Sea. The Straits of Malacca, one of the world's busiest shipping passages, is a narrow sealane between Peninsular Malaysia, the Indonesian island of Sumatra and Singapore. The South China Sea is significant because of its continental shelf which is extremely nutrient rich and able to support a remarkable diverse of species.
Malaysia has a hot and humid tropical climate marked by seasonal variations in rainfall. Generally, the climate is influenced by the northeast and southwest monsoons. The annual mean rainfall in Peninsular Malaysia is approximately 2,540 mm, with most precipitation occurring during the southwest monsoon (September to December) as opposed to East Malaysia which receives most of its rainfall during the northeast monsoon (October to February). Sabah's average rainfall is 2,630 mm and Sarawak's is approximately 3,850 mm. There is, however, great variation in rainfall between locations. Northern Perlis, for example, receives only half of Terengganu's annual rainfall on average, whereas parts of eastern Sarawak receive more than 5,500 mm of annual rainfall. Mean annual temperature is 27°C with a diurnal range of 9°C. Relative humidity is high (85 - 95%), especially in the coastal areas.
The majority of the population of Malaysia are Malays and Bumiputeras (59%), Chinese (32%) and Indians (8%). About 80% of the total population resides in Peninsular Malaysia, with 9.9% in Sabah and 9.4% in Sarawak. Sabah and Sarawak have largenon-Malay indigenous populations compared to the Peninsular. In Sarawak, there are 28 different tribal groups with the Iban as the largest ethnic group, accounting for 30% of the population. The Kadazan are the dominant ethnic group in Sabah. The three main groups of aboriginal peoples, or orang asli, in Peninsular Malaysia are the Negritos, Senoi and the Proto-Malays.
Status of water resources
There is abundant water in Malaysia as a whole. The annual rainfall over the Malaysian land mass amounts to 990 billion m3, of which some 566 billion m3 appears as surface runoff and about 64 billion m3 recharges groundwater.The river systems in Malaysia are an integral part of the water resources system. There are more than 100 river systems in Peninsular Malaysia and more than 50 river systems in Sabah and Sarawak. River systems as a whole, with or without impounding reservoirs, are estimated to contribute about 97% of the raw water supply source.Due to population growth, coupled with rapid agricultural and industrial development, the availability of adequate water resources to meet increasing water demand is fast becoming a pressing issue. The definition of river basin has not been provided for under any Malaysian law. In the past, water resource management placed little emphasis on river basin management and development as a whole. Thus little attention has been given to overall river basin management. Some work has been carried out by the Department of Irrigation and Drainage and the Public Works Department to create a management information system (MIS) for all water-resources-related activities in the major river basins of the country. In total some 41 river basins throughout Peninsular Malaysia were identified, most of which lie within the respective states. Only major ones were found to transcend several states.
Water Quality Status of River Basins
In year 2006, the number of rivers in the cleanest category was almost double that of 2005.The number of polluted river basins were also down by more than half. Only seven of Malaysia’s 146 river basins were categoried as polluted in year 2006, down from 15 the year before.All the polluted river basins were in Peninsular Malaysia, with Johor topping the list.
Source: Environment Quality Report 2006
To read more about river issues in Malaysia go to
Malaysia Rivers Network or
Kerana Jaya Lakes Rehabilitation Programme or
Sungai Pencala Rehabilitation Programme
Department of Environment Website