Water crisis deepens in Chattogram city as drought, algae-contaminated river compound woes

The unavailability of sufficient water has caused severe suffering for city dwellers during summer, disrupting daily activities and leading to additional expenses for buying water

Mitoon ChowdhuryChattogram Bureaubdnews24.com
Published : 18 April 2023, 09:13 PM
Updated : 18 April 2023, 09:13 PM

Chattogram's water crunch has deteriorated due to lack of rainfall, as algae accumulation in the Karnaphuli River impedes WASA's purification efforts, leaving residents to suffer in the urban heat. 

The Chattogram Water Supply and Sewerage Authority is rationing the daily water supply to city areas as water purification is deficit by roughly 100-120 million litres. 

The unavailability of sufficient water has caused severe suffering for city dwellers during summer, disrupting daily activities and leading to additional expenses for buying water. 


Water released from the Kaptai dam flows swiftly and blocks saltwater in the high tide via the Karnaphuli River from entering the Halda River. Water from Kaptai also enters the Halda River at regular times, reducing the salinity. 

The prolonged heat and dearth of rainfall have put immense pressure on the city's water supply and Kaptai Lake. The lake's inadequate water release from the dam led to increased saltwater ingress into the Halda River. 

During the dry season, from November to March, if the Kaptai dam does not release enough water, the salinity level in the Halda River rises. 

Water levels upstream of Kaptai Lake have been receding since March, with increasing heat causing a further decrease in the water level, creating conditions favourable for algal growth. 

The algae that originated in Kaptai Lake has now spread to Karnaphuli River, where it is impeding water purification efforts. 

Chattogram WASA issued an emergency public notice on Monday, stating that an insufficient amount of rainfall has led to a significant quantity of water contaminated with algae entering Karnaphuli River from Kaptai Lake and its tributaries. 

The filter systems at the Sheikh Hasina Water Treatment Plants- 1 and 2 in Karnaphuli are being obstructed due to the excessive amount of algae in the extracted river water, Chattogram WASA Chief Engineer Maksud Alam told bdnews24.com. 

He also said that they are attempting to reduce the algae by using chemicals. 

The combined water treatment output of the two plants located in Karnaphuli on Tuesday amounted to 230 million litres, which is lower than their total purification capacity of 280 million litres per day. 

Maksud said the salinity levels in Halda River are considerably high because of the lack of water supply from Kaptai Lake. 

According to him, the salinity level in the Halda estuary section was measured at 3000 mg/litre on Wednesday, which is well above the permissible level of 600 mg/litre. 

“Today, a total of 60 million litres of water have been processed at Mohra water treatment plant phase-1, although the plant has the capability to treat up to 90 million litres.” 

Sheikh Russel Water Treatment Plant at Madunaghat, six kilometres upstream of the Halda-Karnaphuli confluence, requires 90 million litres of water daily, and WASA officials said that its purification process is functioning normally. 

WASA has a daily treatment capacity of 500 million litres through its four water treatment projects and 50 deep tube wells. The daily water requirement for the city is approximately the same. 

On Tuesday, WASA purified 380 million litres of water, resulting in a shortage of 120 million litres. The day before, the deficit was roughly 130 million litres of water, and on Saturday, the deficit surpassed 140 million litres of water. 

Mohammad Omar Faruque, an associate professor of the botany department at Chattogram University, told bdnews24.com that the growth of blue-green algae is rapid in slow-moving water and high temperatures. Currently, these two conditions are occurring simultaneously. 

Omar warned that if there is no rainfall, the water levels in the rivers will decrease further, leading to more crises as the temperatures continue to rise. 

The increased inflow of seawater into the Karnaphuli and Halda rivers can introduce saltwater algae into the system. 

“The algae currently present in the river is of freshwater origin and has a specific odour. In contrast, the smell of saltwater algae is more intense than that of freshwater algae.” 


Sakhawat Hossain, a Dhanialapara resident, complained to bdnews24.com about the irregular water supply during Ramadan. He said that the water sometimes came in the morning and sometimes at night, causing him inconvenience and uncertainty. 

Moreover, he said, the available water now has an unpleasant odour and a salty taste, which was not the case earlier. 

Sakhawat added that the heat was causing distress to children and elderly people in the household, exacerbating the difficulties caused by water scarcity. 

Several city areas, such as Gosaildanga, Agrabad, South Central Halishahar, Rahmatganj, Lalkhan Bazar, Dewanhat, OR Nizam Road, Sholshahar, Kadmatli, Bissho Colony, Muradpur, Baklia, Chawkbazar, and Chhotopool, have been experiencing extreme water supply disruptions for the past week. 

Residents queue up with pitchers and buckets at roadside water taps early in the morning, hoping for the arrival of water. 

According to Ayesha Akhter, a homemaker from Rahmatganj, the water supply lasts for only 20-30 minutes in the morning, leaving her unsure whether to use it for bathing, washing clothes or cooking. The water scarcity has become so acute that it is impossible to cook on some days. 

Lokkhi Chowdhury, a resident of the city’s Askar Dighir Par area, shared that they have only received supply water for three days in the last week and have had to manage cooking with water they bought. 

She expressed frustration with the unpredictability of the water supply and the difficulty of coping with the situation in hot weather. 


Due to insufficient water purification, WASA has resorted to the rationing water supply to different areas of the city. 

Maksud said that the water supply had been increased today in neighbouring areas such as Lalkhan Bazar and OR Nizam Road, and will be extended to Dhanialapara, Kadmatli, Dewanhat, and Sholshahar tomorrow. 

The WASA chief engineer deemed the current situation as "natural” and said that they were facing a lot of pressure due to the algae outbreak. 

He mentioned that the situation could improve if it rains. 

[Writing in English by Arshi Fatiha Quazi]