Sylhet Bureau :
After two rounds of floods in Sylhet, there is a threat of flooding again. Due to heavy rainfall in the northeastern part of the country and Meghalaya-Assam in India, the water level of the Surma and Kushiyara rivers has already crossed the danger level in Sylhet. The Flood Forecasting and Warning Center has forecast floods in Sylhet, Sunamganj and Moulvibazar due to the increase in the water level of the Surma and Kushiyara rivers.
In a warning issued on Tuesday (September 16), it was said that the water level of these two rivers has increased in the last 24 hours and it may flow above the danger level in the next three days. As a result, there is a risk of flooding in the low-lying areas. The water level of the Kushiyara river is already flowing 25 centimeters above the danger level at Amalshid point in Sylhet.
The center said that in the last 24 hours, heavy to very heavy rainfall has occurred in various places of Sylhet, Rangpur and Mymensingh divisions and upstream in Meghalaya, Assam and Mizoram in India. In addition, heavy rains are forecast in various states of India including Rangpur, Rajshahi, Dhaka, Mymensingh, Chittagong and Sylhet divisions until next Wednesday. Due to this, the water level of several rivers in the country may increase. Among them, the water level of Teesta and Dudhkumar rivers in Rangpur division may cross the danger level, and the water level of Dharla river may flow within the warning level. This may cause flooding of the low-lying areas of Lalmonirhat, Nilphamari, Rangpur and Kurigram.
The water level of Gomti, Muhuri, Selonia and Feni rivers in Chittagong division has increased. The water level of these rivers may increase further in the next two days. The water level of Muhuri, Selonia, Feni and Halda rivers may flow within the warning level and flood the low-lying areas of Feni and Chittagong districts.
On the other hand, the water level of Sari-Goain, Jadukata, Someshwari, Bhugai, Kangs and Jinjiram rivers in Sylhet and Mymensingh divisions is also increasing. The water level of these rivers may reach the warning level in the next three days. This may cause short-term flooding in the low-lying areas of Sylhet, Mymensingh, Netrokona and Sherpur districts.
Deepak Ranjan Das, Executive Engineer of the Water Development Board, Sylhet, said that it has been raining in Sylhet for the last three days. There is a possibility that this trend will continue for another three days. In addition, excessive rainfall has increased in the areas bordering India, which has created a flood situation there. These waters go to the Bay of Bengal via Sylhet. Therefore, short-term floods may occur in Sylhet.
Some blame the Itna-Mithamain-Ashtagram road as the reason for frequent flash floods in Sylhet, some blame the navigability crisis of the rivers in the region, and some blame the excessive rainfall in India.
Recently, a study by a group of researchers from NASA’s Goddard Space Flight Center in the United States, North Carolina State University, the Institute of Tropical Meteorology in India, and Jahangirnagar University in Bangladesh has revealed important information in this regard.
The study, published in the Journal of the Royal Meteorological Society, says that while the amount of monsoon rainfall has been decreasing in the Meghalaya-Assam region of India and Sylhet region of Bangladesh over the past four decades, the incidence of extremely heavy rainfall in a single day has increased fourfold.
The study said that climate change is changing the rainfall pattern in the region, which is causing frequent flash floods in the Sylhet region. The study defined extremely heavy rainfall as more than 150 millimeters of rainfall in a single day.
Officials from the Bangladesh Meteorological Department and the Bangladesh Water Development Board, as well as an expert professor from the Institute of Water and Flood Management at the Bangladesh University of Engineering and Technology (BUET), have also observed an increase in extreme rainfall as one of the reasons for the recent floods and waterlogging.
The study found that on June 17, 2022, when the catastrophic floods occurred in the Sylhet region, Cherrapunji in the Indian state of Meghalaya recorded 972 millimeters of rainfall in a single day.
Within hours of the heavy rains, vast areas of Sylhet and Sunamganj were submerged in heavy water. 84 percent of Sylhet and 94 percent of Sunamganj were affected by the terrible floods.
On May 29, Cherrapunji received 634 millimeters of rainfall in a single day. That night, five upazilas of Sylhet district were flooded by flash floods. As a result of this flood, Cherrapunji received another 349 millimeters of rain in a single day on June 13. As a result, the flood situation became even more dire in Sylhet the next day.
However, not only in Meghalaya, but on June 9, Sylhet city experienced severe waterlogging due to 220 millimeters of rain in three hours. Later, it repeated on June 13. Most of the low-lying areas of the city were again waterlogged due to 220 millimeters of rain in a span of 6 hours.
Deepak Ranjan Das, Executive Engineer of Bangladesh Water Development Board, Sylhet, said, “Heavy rainfall in this region in a single day, especially in Meghalaya, India, upstream of us, is creating a flood situation. Because our northeastern river system cannot transport a large amount of water in such a short time.”
Shah Mohammad Sajeeb, Assistant Meteorologist of the Meteorological Department, Sylhet, also agreed with this.
A mapping of flood damage in the Surma River Valley in Sylhet city by a group of researchers from Shahjalal University of Science and Technology has mentioned that the Surma River can transport 321.35 cubic meters of water per second in the urban area, which is not enough to transport heavy rain water.
Professor AKM Saiful Islam of the Institute of Water and Flood Management of Bangladesh University of Engineering and Technology (BUET) said, “Haors and rivers play an important role in retaining and transporting heavy rain water coming down from upstream. But continuous unplanned development projects are isolating the connected haors. As a result, frequent floods are occurring.”
He said, “Not only rivers and haors, but canals in urban and urban areas are being encroached upon and filled. As a result, extreme waterlogging is occurring during heavy rains. In addition, land erosion is occurring due to cutting down hills and dunes and indiscriminate deforestation, which is filling the bottom of all types of wetlands, including rivers and haors, making the flood situation miserable.’
