For those living in Chattogram's Agrabad CDA residential area, the knowledge of the tide times and a tide chart is a must.
It might sound odd for living on land and working in offices or going to schools, but people living there must know when the tide water would come in and the roads and their lower level floors would go under water. This is what living in the high class residential area in the city is now where once the rich and famous of Chattogram used to reside.
When the neighbourhood goes under water at high tide, people usually stay cooped up indoors until the seawater recedes. Low-lying areas remain waterlogged for at least six hours a day.
"Tidal water stays for at least three hours. We have a calendar for tidal prediction and our days begin according to it," said Jashim Uddin, a resident at the posh area located at the heart of Chattogram city.
This is how the residents are coping with the twice-a-day inundation caused by high tide in the Bay of Bengal.
Not only Agrabad alone, around 69% of the areas of the port city get affected by high tides to various extents at different times, according to a survey of the Bangladesh Public Works Department.
Experts say Chattogram city, home to more than six million people, is highly vulnerable to flooding caused by tidal surges.
The city has its own unique struggles when it comes to adapting to the inevitable global climate change, they add.
Agrabad's elevation is 0.42 metres from the sea level but the daily average high tide is at least 2.51 metres, according to the Survey of Bangladesh and Bangladesh Army data.
The highest water level during spring tide has been recorded at 2.76 metres in the area
During a new moon, full moon and inclement weather condition, the situation turns worse when tides rise one or two metres higher than the regular one.
Flooding caused by the 2.51-metre high tides owing to a rise in water level in the River Karnaphuli –connected to the Bay of Bengal – forced many residents to abandon their houses.
Many well-off people have shifted their residences to Chandagaon and Khulshi residential areas.
The modern residential area built on 82.18 acres of land has now become almost abandoned.
Along with the flooding, salinity left by the sea water causes severe damage to structures in the city.
On a recent visit, it was found that rainwater was being pumped out from the residence of Saifuddin Malek, a US expatriate, built on 5,408 sq. metres of land on Road 22, to save it from inundation by tidal water.
"We have spent Tk30 lakh to build a higher boundary to protect the house from flooding. But we are still not feeling safe," said Malek.
The Chattogram Development Authority (CDA) residential area in Agrabad was home to the affluent people in the 1960s. High-ranking government officials, noted businessmen and politicians lived there as well.
Owners forced to abandon multi-million Taka houses
Two duplex houses on Road 21 in the CDA residential area were once home to late former minister LK Siddiqui and his wife Mahmuda Siddiqui.
The houses were built on 3,380 sq. metres of land in 1977. The Siddiquis lived there until 1992. But they had to completely abandon their homes in 2018.
"We moved to Dhaka in 1992 when water started entering the ground floors of the houses. We used to stay there occasionally while visiting Chattogram. But in the last 10 years, we could not stay there because of water," said Assan Siddiqui, eldest son of LK Siddiqui.
Mir Rezuan Hossain Tipu, former mariner and shipping businessman who built his home on 1,521 sq. metre of land on Road 21 in 1976, told The Business Standard, "We did not have this problem – water entering houses – until 1990. Gradual inundation of the area began after that year. We started elevating our ground floor. From the 1990s to 2019, I elevated my ground floor by around five feet, but it was useless as the water level continues to rise every year."
"In January this year, we had to abandon the house leaving behind a lot of memories of my childhood and of my parents. We are now living in a rented house," he said.
Home owners in the area also have to face financial losses as all 1,500 of them had to rent out their properties at less than market price, he said.
CDA Chief Engineer Kazi Hasan Bin Shams told The Business Standard, "We elevated roads by three feet last year, but they became submerged again this year. Tidal water is the main problem in the residential area. We are building tidal regulators in Maheshkhal. I hope it will save the area."
Agrabad commercial hub is not spared
The Agrabad commercial area – home to most business houses, including the World Trade Centre, Chattogram – in the port city is also affected by tidal water.
In the last two to three years, water started creeping up to the front of the trade centre opened in January 2016. Last year, tidal water flooded the whole area.
"I had not seen tidewater flooding the Agrabad commercial area two years ago. I could not even think of tidal water in front of the trade centre. In the last two years, we have seen the road in front of the lavish business centre go under water," said Mahbubul Alam, president of the Chattogram Chamber of Commerce and Industry.
The sea level rise and flooding not only hampers people's lives but also severely affects businesses in the commercial area.
The country's largest wholesale commodity market in Khatunganj and Asadganj loses at least Tk1,000 crore annually for the damage of goods and businesses from seawater flooding, claims Khatunganj Trade and Industries Association.
Inundation affects more city areas
Sea water rises by 0.5-2.5 metres in 18% of Chattogram city areas, including the CDA residential area in Agrabad, East Bakalia, south Bakalia, Halishahar, Sholokbahar, Muradpur, and Bahaddarhat. High tides ranging between 2.5 and 2.76 metres regularly submerge these areas.
In 51% of the areas, the water level rises by 2.5-4.5 metres, and they are mostly inundated during the rainy season, new moon, full moon and cyclones.
Chandagaon, Mohora, Chaktai, Kahtunganj, Asadganj, Chawkbazar, Patenga, and Kattoli areas partially go under water during high tides, said Lt Col Mohammad Shah Ali, director of a project for mitigating waterlogging and flooding in the city.
Chattogram Maa-O-Shishu Hospital, Sabujbag residential area and Halishahar adjacent to the CDA residential area also get flooded.
Experts attributed this every day flooding to the rise in sea level caused by global climate change.
Sholokbahar is the worst-hit area where the elevation is only 0.19 metres but the average high tide level is 2.50 metres.
The Halishahar residential area started experiencing waterlogging after 2005.
"After 2005, water started coming slowly. Now the area is inundated with at least one and a half metre high tide," said Golam Mostafa, president of Halishahar K and L Block Samaj Kalyan Samity.
"House rent has fallen by at least 40-50% because of the tide water flooding the area regularly," said Mostafa.
Only 22% of areas have elevations between five to 30 metres, which so far is considered safe from flooding. Nine percent of areas have an elevation of 30 metres to over 90 metres, which is considered a hilly area.
In 2017, the US National Aeronautics and Space Administration (NASA) estimated that Chattogram would be submerged in the next 100 years and over the next century melting glaciers could raise the sea level by 14.01 centimetres.
Every year, new areas in the port city are being inundated and tidal height is breaking previous records. On August 21-22 this year, tidal water for the first time flooded different jetties of the Chattogram port, causing exporters and importers to worry about damage to their cargoes.
On August 21, the tide was 4.81 metres high in Karnaphuli while it was 4.66 metres the next day.
What experts say
Professor Md Reaz Akter Mullick, head of the urban and regional planning department at Chattogram University of Engineering and Technology, told The Business Standard that sea level rise had greatly impacted Chattogram.
"Every year, the water level is getting higher while water retention areas [water bodies] are decreasing. Such areas decreased by around 50% in the last couple of decades," he said.
"We have to build tidal regulators so that tidal water cannot enter the city. We have to build water reservoirs in the city to store floodwater," said AKM Rezaul Karim, head of city planning of Chattogram City Corp, also a climate change expert.
"Pumps with generator facilities should be installed beside canals and water bodies so that additional water can be pumped out to the River Karnaphuli," said Karim, also the chief city planner of Chattogram City Corporation.
"There should also be green space and more canals," he added.
Government's move to regulate tidal water
The CDA and the Bangladesh Water Development Board are building 40 tidal regulators to prevent seawater intrusion into the city through the Karnaphuli.
Construction of five regulators are going to be completed within next year under a project titled "Canal re-excavation, expansion, renovation, and development to ease waterlogging in Chattogram city," said Project Director Lt Col Mohammad Shah Ali.
The water development board has also undertaken a Tk1,620 crore project titled "Flood control, addressing waterlogging and improvement of drainage facilities of Chattogram metropolis to mitigate Chattogram waterlogging".
Under the project, 23 tidal regulators will be built at the Chattogram airport, Moheshkhal, Shah Amanat Bridge, Kalurghat, and mouth of the River Halda.
The CDA is building another 12 regulators in Chaktai Khal and Rajakhal areas.
Professor Mullick said there should be a management solution to control dumping of waste in the drains.
"Otherwise, tidal regulators will not bring any benefit."