Preliminary findings of a comprehensive spatial study by the government have found an alarming decline in the rivers, canals, ponds and wetlands of Dhaka and its surrounding areas over the past 250 years.
The region’s surface water area declined by 83.40 percent, from about 383 square kilometres in 1776 to only 64 square kilometres in 2025, according to the study being conducted by the Urban Development Directorate (UDD) under the housing and public works ministry.
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The findings were presented at the study’s first consultation workshop at the UDD conference room yesterday.
The study is based on James Rennell’s 1776 Map of Dacca and satellite imagery analysed using Google Earth Engine from 1990 to 2025. The historical map provides a baseline for assessing the spatial extent of water bodies, while multi-temporal satellite imagery has been used to analyse their changes over the period from 1990 to 2025.
The study covering 3,126.64 square kilometres across Dhaka and seven peripheral districts also uses institutional records, field surveys and GIS-based spatial analysis to trace changes in the region’s hydrological network.
The study, titled “Identifying and Mapping the Disappearing Water Bodies of Dhaka and Peripheral Region: A Study Using Historical Maps and Satellite Imagery,” was launched in May and is expected to be completed by February 2027.
“The decline represents a loss of nearly 319 square kilometres of surface water and water-retention areas. Rapid urban expansion, unregulated landfilling, riverbank encroachment and the filling or enclosure of open canals are primarily responsible for the loss,” said research adviser M Mahmud Ali, director of UDD.
Several historic waterways, including the Konai, Painar, Pandu, Narai and Ati rivers, have been pushed to the brink of disappearance, according to the preliminary findings.
Dholai Khal, once an important waterway for navigation and flood drainage, has also been reduced to fragmented remnants, Mahmud said.
The research was officially launched at an inception event on May 17, 2026, attended by Ahammad Sohel Monzoor, state minister for housing and public works.
The workshop brought together urban planners, hydrologists and representatives of government and research organisations to discuss the preliminary findings and possible measures to protect and restore Greater Dhaka’s remaining waterbodies.
The study aims to identify and map disappearing waterbodies, according to Mahmud.
It will identify historical and existing waterbodies, assess the extent of the loss of rivers, canals and ponds, and identify priority locations for canal re-excavation as promised by the government in its election manifesto, he said.
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It will also assess connectivity between major rivers and canal networks, and formulate recommendations for restoration and sustainable water management, he added.
Mohsinat Nasrin, a planner at UDD, said Dhaka once had around 344 kilometres of canals, of which approximately 124 kilometres have now been lost. Around 60 percent of the city’s waterbodies have disappeared over the last 44 years, she said.
Prof Ishrat Islam of the Department of Urban and Regional Planning at Buet, stressed the need for initiatives to curb pollution, saying household and industrial waste plays a major role in polluting ponds, canals, rivers and other waterbodies.
She also called for an integrated approach to waterbody conservation, particularly as many have already disappeared.
Helemul Alam, a writer with interests in canals and ponds of Dhaka, said connectivity between canals and rivers around the capital was disrupted during the construction of flood-protection embankments following the 1988 flood.
The then government had approved 11 guiding principles, including a recommendation to keep canal mouths connected to rivers. However, the recommendation was ignored, said Helemul, who is also a senior reporter at The Daily Star.
According to him, 54 small sluice gates were constructed along the 36-kilometre embankment from Tongi to Kellar Mor, while a 3.8-kilometre floodwall was built from Kellar Mor to Postogola. As a result, boat communication was permanently disrupted.
He called for initiatives to reopen canal mouths and restore connectivity between canals and rivers wherever possible.
