Groundwater level improves during flood

  • আপডেট টাইম : September 07 2020, 20:03
Groundwater level improves during flood

Amdadul Haque:

This year’s flood will help to recharge groundwater level, ensuring the availability of water during the dry season across the country, says a study.

Besides, it also says the deluge will also improve the quality of underground water.

Apart from these, the flood continued depositing nutrient-rich fine-grained sediments to lands making them more fertile.

The groundwater level will remain three to four feet above the ground during the dry season as it has been submerged for about two months. This will increase irrigation facilities in summer.

Experts believe that this year’s irrigation season will save farmers at least Tk 300 crore. When the water level goes down one foot, the farmers have to spend an additional Tk 100 crore a year.

This time the water level will increase by 3 to 4 feet in some areas due to prolonged floods. In addition, rising groundwater levels will reduce arsenic outbreaks and landslides.

The main source of stored water in the groundwater table is water leaking from surface water bodies (rivers, canals, beels, ponds, etc.). The water flows from the catchment area of the surrounding area where the water is collected.

In addition, rainwater, irrigation water penetrates the upper soil layers and slowly accumulates in the lower layers after reaching the surface. Groundwater levels rise when rainfall is high and water accumulates above the surface for long periods of time.

According to a survey conducted by the Water Resources Engineering (WRE) Department of Bangladesh University of Engineering and Technology (BUET), 61 per cent of Bangladesh was submerged in 1988 and 68 per cent in 1998, raised the groundwater level by up to 4 feet.

This year’s floods have inundated 41 percent of the country. At the same time, the amount of rain this time is more than other times. All in all, the groundwater level will be three to four feet above the ground during the dry season.

Bangladesh Agricultural University’s Professor of Soil Science Rafiqul Islam said that vast areas were under water as the floods were prolonged. There is still water in many places. This will naturally increase the groundwater level. In that case, depending on the type of soil, groundwater level will increase by 3 to 4 feet somewhere. Now the water level is high everywhere in the rainy season.

“One of the benefits of prolonged flooding is the increase in groundwater levels. This leads to increased irrigation facilities. Irrigation will save the farmer. In addition, as a result of floods, a lot of silt falls on the land and the land becomes fertile which increases crop production. Rising groundwater levels also reduce arsenic outbreaks and landslides,” he added.

According to the Bangladesh Agriculture Development Corporation (BADC), the country is currently pumping water by 1.7 million shallow tubewells. These can draw water from 22 to 24 feet below the ground. But now in many areas water is not available even 24 feet below the ground.

In this situation, the farmers of all those places are digging five more feet of soil and installing shallow tubewells. Even after that water is not available in many places. In the dry season, about five lakh shallow tubewells become useless in Bangladesh.

This time the groundwater level will be three to four feet above the ground during the dry season as a result of being submerged in the flood water for a long time. The groundwater level will be five to six feet above the floodplain. The water level in the area will be between 18 and 24 feet. As a result, shallow tubewells can easily draw water from the ground during the dry season.

Agricultural economists expected that, This time, the increase in groundwater level due to prolonged floods will save farmers at least Tk 300 crore in irrigation.

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