Chattogram Wasa’s water supply improves as salinity decreases
The project includes installing 55 deep tube wells, replacing old pipelines, and strengthening monitoring systems to ensure a more stable water supply
Water production in Chattogram is gradually returning to normal after a temporary decline caused by increased salinity in the Halda River.
However, concerns remain over a potential resurgence of salinity before Eid if rainfall remains scarce.
Salinity levels, which had surged earlier this month, have now fallen below 1,300 milligrams per litre, allowing production to rise from 42-43 crore litres to 47 crore litres daily.
Meanwhile, a Tk3,921 crore water supply development project, aimed at reducing water loss and meeting rising demand, is awaiting approval from the Executive Committee of the National Economic Council (Ecnec).
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The project includes installing 55 deep tube wells, replacing old pipelines, and strengthening monitoring systems to ensure a more stable water supply.
According to Chattogram Wasa, salinity levels had increased in the Halda River, affecting two key water treatment plants: the Madunaghat Water Treatment Plant (capacity of 9 crore litres per day) and the Mohra Water Treatment Plant (capacity of 9 crore litres per day).
Water production at these plants had fallen by 3–5 crore litres per day due to high tide-related salinity spikes, requiring shutdowns for five hours twice daily.
In early March, salinity levels ranged from 1,900 to 2,500 milligrams per litre but have since decreased to below 1,300 milligrams.
Additionally, the water level in the Karnaphuli River has dropped during low tide, reducing output at Karnaphuli Water Treatment Plants 1 and 2, which together produce 28 crore litres daily.
Water production at these facilities has declined by 2–3 crore litres per day.
Overall, Chattogram Wasa's four treatment plants saw a reduction of 6–8 crore litres, bringing total production down from 50 crore litres to 42–43 crore litres in early March. Production has now improved to 47 crore litres daily.
Maksul Alam, chief engineer of Chattogram Wasa, told The Business Standard, "Demand is higher than water production. The crisis worsens during summer when salinity rises and water levels drop. Continuous rainfall for 4–5 hours in Patenga, Chattogram city, and Kaptai, Rangamati, could improve conditions. Climate change is affecting production, and projects have been undertaken to address these challenges."
Proposed projects for water supply development
To enhance Chattogram's water supply system, Wasa is planning a Tk3,921 crore project to strengthen monitoring, replace pipelines, and install smart meters.
The World Bank is expected to provide loan assistance for the project, which includes replacing 376 kilometres of pipelines, installing 90,000 smart meters, and establishing 46 District Metering Areas (DMAs) to improve supply and monitoring.
In addition, 55 deep tube wells will be installed to supplement water supply until a new treatment plant is operational. This initiative, expected to extract 5 crore litres of water daily, is currently under review by the Planning Commission and awaits placement at an Ecnec meeting.
Addressing long-term salinity issues
Chattogram Wasa is also working on a $400 million project to mitigate salinity, which has become a prolonged issue.
Previously, salinity in the Karnaphuli and Halda rivers lasted 15–20 days per year, but reduced rainfall and lower water discharge from the Kaptai hydroelectric power plant have extended this period to nearly two months in recent years.
In August 2022, French consulting firm Suez submitted a concept paper proposing an alternative intake station, a pre-settlement reservoir, and a new water treatment plant.
The Economic Development Cooperation Fund (EDCF) has expressed interest in financing the project and will send consultants to assess its feasibility.
Infrastructure plans for future demand
The proposed project includes three infrastructure phases to meet future water demand.
The first phase involves constructing an intake station and pre-settlement reservoir at the Bhandaljuri Water Supply Project in Boalkhali to collect 84 crore litres of raw water daily.
Additional plans include a water pump station with a 63 crore litre daily capacity, a river crossing pipeline under the Karnaphuli and Halda rivers, capable of transporting 42 crore litres daily from Bhandaljuri to Mohra and Madunaghat treatment plants, a new 20 crore litre daily capacity water treatment plant at Mohra, and pipelines and reservoirs extending from Mohra to Bayezid Link Road to expand service coverage.
Since Mohra Water Treatment Plant has available land, the concept paper suggests constructing two additional treatment plants in later phases.
Chief Engineer Maksud Alam stated, "The water supply development project is awaiting approval. It will reduce non-revenue water losses and improve distribution to Wasa customers. Additionally, 55 deep tube wells will help meet demand. EDCF has agreed to finance the intake transfer project and will send a consultant team to verify its feasibility."
