Groundwater Scarcity of Dhaka City

As far as I remember, the day was 15th of November, 2017. The weather was hot and sunny and sky was so hazy. In that tiring day, I along with my friend went to one of the most crowded slums of Dhaka city named Kallayanpur Slum regarding some research activities. After taking breakfast there, I ordered a cup of tea. While sipping tea, I noticed a group of women standing in a queue holding their vessel. Actually, they were waiting for water, but after sometimes I observed that some women were leaving the place without fetching water with them. Their face was filled with anxiety. I talked with one of them. “This is a regular case here. Water is not available all the time. If you want to get it, you have to stand in a queue earlier in the morning. Otherwise, it would be very difficult” uttered by a woman with a grim expression on her face. I have read numerous articles about the water problem of Dhaka city but that day I realized the real scenario of water scarcity in Dhaka city.

Water scarcity is considered to be one of the most serious issues afflicting Dhaka city. The city dwellers depend largely on groundwater in order to meet their daily water demand. Groundwater functions as a great source for the domestic, agricultural, industrial and waste dumping purposes. It is found underneath the earth’s surface and the pore spaces of soil. The uppermost portion of the saturated zone is defined as the water table. Groundwater passes at a slow rate and ultimately emerges by discharging into channels, streams, lakes and swamps.

Statistical evidence shows that between 1970 and 1990, there was a fast growth of groundwater exploitation in most portions of the developing country. Despite the enormous groundwater resources the development of water resources has not been advanced and kept pace with high population growth. In developing countries like Bangladesh, a very significant role is played by groundwater to meet the daily demand of water of its residents.
Dhaka city and its adjacent metropolitan areas have a population of over 15 million and evidently, the population is growing fast at a rate of about 3.6 percent. The increasing population of the city is exerting immense pressure on groundwater resources and if the trend continues, it would be very difficult to keep the water table within the extraction limit. With a view to mitigating the daily demand of the residents of the city, the city authority depends predominantly on groundwater. Groundwater and surface water contributes about 85.82 percent and 14.18 percent respectively in order to meet the demand of the residents of Dhaka city. On the other hand, approximately 87 percent of the supplied water is extracted from groundwater. Besides this, the water table was 18-22 meter below the ground before the mid-20th century in and around Dhaka city as water table started diminishing since 1980 due to hasty urbanization. Currently, in most areas of this city, the average groundwater depletion has been recorded to be around 2-3 m/year. Most parts of the Dhaka city are covered with the impermeable surface which does not allow rainwater and run-off to penetrate into the ground. Groundwater of Dhaka city is pumped at a rate which cannot be replenished by the natural process, especially the central part of Dhaka city is very much vulnerable which gradually rises towards the periphery as highest depletion rate has been recorded here. For example, according to Bangladesh Water Development Board (2014), in 2010, the depth of groundwater table in Dhanmondi area was approximately 66 meters below the earth surface while in 1980, 1990 and 2000 the number was 10.12 meters, 15. 4 meters and 40.12 meters respectively. Such depletion of the water table is caused by overexploitation of the huge population of Dhaka city and its enormous pressure on water resource and lack of recharge facilities.

groundwater_scarcity_dhaka

Source: Bangladesh Water Development Board (2014)

So, necessary steps should be undertaken to solve this vital issue and not to procrastinate. Rainwater harvesting is one of the effective solutions to lessen the water crises problem. It can be implemented by using streets, pavements, rooftops and parks. Recycling and reusing of wastewater is another option to mitigate this problem. Our government should increase undertaking of scientific researches using geospatial technologies to understand the hydrogeological condition and rainfall pattern of our country. The planning bodies and policy makers of our country should commence necessary steps as early as possible. Public awareness programme and capacity building programme should be taken under consideration to solve this issue. A joint collaboration of government and non-government organizations is inevitable to ease the present scenario of groundwater fluctuation. In this way, the balance of nature would be maintained and an uninterrupted supply of pure & pollution free groundwater would be available for the residents of this city.

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