Projects under way to mitigate floods, prevent saltwater intrusions in Sungai Muar

07 Sep 2022 08:41am
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"The country is like a human body and its rivers are akin to the blood vessels that carry life-giving blood.”

This is the fitting description given by Environment and Water Ministry secretary-general Datuk Seri Dr Zaini Ujang - who is also an environmental expert - to illustrate the importance of rivers for the socioeconomic development of civilisation.

In Malaysia, the main function of rivers is to supply raw water for public use. In the interior parts of Sabah and Sarawak, rivers also serve as "roads” for the local communities,

However, over the decades, pollution resulting from the exploitation of forests for development purposes is threatening to harm the ecosystems of this nation’s rivers, particularly those located in Selangor, Johor and Penang.

The 329-kilometre-long Muar river is no exception.


The Muar river basin is among the 189 river basins in this country. This river network is unique in that a small part of it has its origins in Pahang while the rest originate from a hill in the Titiwangsa Range in Kampung Talang, Negeri Sembilan. The estuary, meanwhile, is situated in Tanjung Emas in Muar, Johor.

In short, the Muar river flows through several towns, among them being Kuala Pilah and Bahau in Negeri Sembilan, and Segamat, Pagoh, Tanjung Agas and Muar in Johor.

Providing a brief history of this river, Azmi Ibrahim, director of the Water Resources Management and Hydrology Division at the Department of Irrigation and Drainage (DID), said Parameswara (the founder of Malacca) had apparently attempted to set up a kingdom in Kota Buruk and Biawak Busuk, located not far from the mouth of Sungai Muar, before moving northward to Malacca.

"The mouth of Sungai Muar, that is, Tanjung Ketapang (now known as Tanjung Emas) was then a very famous and busy port, visited by traders from all over the world,” he told Bernama when met recently during a four-day National Water Resources Expedition to Sungai Muar, organised by DID and UNESCO (United Nations Educational, Scientific and Cultural Organisation) as well as several other agencies involved in the management of national water resources and tourism.

The objective of the expedition was to improve knowledge of river water management techniques among the agencies concerned and explore the characteristics and places of historical value found in the Muar river basin.

Incidentally, Sungai Muar’s estuary is home to a variety of fish, lobsters and oysters. According to Azmi, its oysters are said to be among the best in the world.

"There are a lot of oysters along the river bank from the river mouth to Pangkalan Tiram. The fishermen here have, for generations, been diving into the water in search of oysters,” he added.


After Sungai Johor, the Muar river is Johor’s second-most important river. Hence, threats posed by the rapid pace of development or climate change can have an impact on the socioeconomic status of the local community.

Commenting on this, Zaini, who also participated in the expedition, said Malaysia is already facing challenges in terms of its annual average rainfall which, at 2,500 mm, is relatively higher than that of most other countries. For instance, Japan’s annual average rainfall is 1,200 mm, while it is only 1,000 mm for most of the countries in Europe.

"As such, we experience flooding frequently. In 2014, Kelantan faced major floods when 940 mm of rain fell over a period of eight days.

"When this (heavy rainfall) occurs, we must channel the excess floodwater to the sea as soon as possible. To do this, we need to build off-river storage ponds (known as Takungan Air Pinggiran Sungai or TAPS) that can also function as downstream reservoirs in the event of a drought.

"In respect of Sungai Muar (river network), work on a TAPS project has already started at Sungai Jernih, which is one of the tributaries of Sungai Linggi in Melaka,” he said.

Zaini added that Malaysia’s river system is also exposed to the threat posed by saltwater intrusion which occurs when the sea level rises and saltwater overflows into rivers.

He said to check this problem in Sungai Muar, a barrage costing RM100 million will be built on its estuary. A barrage is a type of dam that consists of a number of large gates that can be opened or closed to control the amount of water passing through.

"There had been a case of saltwater intrusion in Sungai Muar when the sea level rose and saltwater flowed over 40 kilometres upstream - many consumers were affected as a result of this,” he said.

He said besides functioning as an agent preventing seawater from entering the river in the downstream area, the outflow of water from the barrage can also be controlled to stop water from draining into the sea unnecessarily.

"Such a measure helps us to overcome the issue of water shortage when a drought occurs,” he explained.


Meanwhile, efforts are also under way to thwart chemical pollution in Sungai Muar. Keeping the river clear of pollutants like ammonia is the main focus of Johor integrated water supply company Ranhill SAJ Sdn Bhd.

Its director of operations Anuar Abdul Ghani said monitoring is carried out by the Water Safety Plan (WSP) team established in 2014, as well as in collaboration with the Johor Water Regulatory Authority and Department of Environment.

"To ensure the safety of water supplied to consumers, Johor was among the first few states to have the WSP in place,” he said, adding that the WSP team monitors the water quality as well as the contamination risks for raw water (in rivers/dams), water treated by the 44 treatment plants in Johor, chemicals used for water treatment processes and treated water in the distribution system.

He said the team is equipped with sophisticated assets, including drones, to monitor pollution and identify the parties responsible for discharging pollutants into the river system.

Anuar added that if ammonia contamination is detected, the water treatment plant concerned would increase the amount of chlorine used to remove the pollutant.

"Most importantly we need to ensure that the chlorine remaining in the water (after the ammonia is removed) is in accordance with the standards set by the Ministry of Health, which is not less than 0.2 mg per litre,” he said. - BERNAMA