Scientific Canal Management Key to Strengthening Bangladesh’s Freshwater Security
Achieving three objectives simultaneously—proper conservation, effective utilization, and enabling water to gradually filter into the ground—could bring a major transformation in the management of freshwater resources in the country. In that sense, the canal excavation and re-excavation programme is undoubtedly a commendable initiative. However, since the baseline quantity of surface freshwater has significantly declined and the natural network of canals and waterways has become silted up or encroached upon, simply excavating canals using traditional methods will not produce optimal results. Engineering considerations in water management must also receive equal importance where necessary.
In Bangladesh, following the monsoon and flood seasons, natural irrigation water availability generally remains sufficient during November, December, and January. However, in February, March, and April—when water demand for IRRI and Boro crops reaches its peak—most canals tend to dry up. Therefore, canal excavation planning must place special emphasis on the capacity to retain water during these three dry-season months.
First, the water-holding capacity of canals will increase in a meaningful way only if excavation is conducted based on scientific calculations of elevation and slope relative to sea level. Isolated excavation of canals will not yield the same benefit. Engineers and officers from local government institutions and regional agricultural offices can easily determine such parameters. Expert resources from the Bangladesh Water Development Board (BWDB), along with specialists from the army and navy, could also contribute in this domain. Their expertise could be utilized in design, mapping, and planning.
Second, in order to retain water during the dry season, control structures such as sluice gates or rubber dams are required at canal outlets. With rubber dams, air can be pumped in during the dry season to raise the water level and store water, and released when necessary to allow water to flow out. During the monsoon, if the structures are fully opened, the canals can remain usable for navigation as well.
Third, interconnectivity among canals and coordinated depth management are essential. Instead of viewing a canal in isolation, the entire canal network and its surrounding agricultural lands should be planned as a single “flow zone,” where water storage targets are determined on a monthly basis according to crop seasons.
Within the canal network, some canals may be deeper while others remain relatively shallow. To maintain water flow, pumps may be used where necessary to regulate the current, while rubber dams or more expensive sluice gates can help increase or decrease water reserves or control waterlogging.
Since canals are not being excavated using machines, care must be taken to avoid overlap between the programme schedule and the rice harvesting period. Adjusting the timing earlier or later could ensure better utilization of idle labour. At the same time, a plan could be developed to measure disguised unemployment before and after the programme. After 1971, when Pakistani and Bangladeshi owners and management were driven out and the jute mills began to deteriorate, and in the context of the 1974 famine, there was an extreme concentration of idle labour in agriculture during 1976–77. At that time, President Ziaur Rahman successfully led what could be termed three major initiatives—canal excavation, the beginning of the ready-made garments industry, and overseas labour migration—thereby achieving remarkable success in a labour transformation (Bangladesh Economy: 50 Years, Chapter One). New academic studies are now needed to examine disguised unemployment across professions as well as the current situation of labour allocation and distribution.
The natural network of rivers and canals that existed in 1977 is no longer the same in 2026. It has undergone extensive changes due to human encroachment and landfilling, natural sediment deposition, and reduced water flow. Therefore, canal excavation should not simply be repeated in the spirit of replicating the “canal cutting programme” initiated by the martyred Zia. Rather, it must be scientifically planned with the objective of creating water reserves for agriculture during the dry season.
The principal objective of martyred Zia was to increase the amount of cultivable land by conserving surface water. Only then will such initiatives truly contribute to the country’s water security and agricultural productivity.
Author: Faiz Ahmad Taiyeb, Technologist, Former Special Assistant to the Chief Adviser
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