Environmental Articles Archive: Water Resources
Web version prepared by BCAS
June, 2008

Arsenic problem in Bangladesh acute due to upstream dam

International expert on Arsenic, Water and Environment Meer Husain said the Arsenic problem in Bangladesh has become acute due to man-made dams in the Trans-border Rivers like the Farakka and Tista Barrages that impede the natural river flow.

Husain, who is also a Geologist in a US college, said the natural river flows have to be resumed by removing the river-dams to solve the arsenic problem, he said. He stressed on the coordination with India to solve the problem.

Meer Husain was addressing a seminar styled "World's largest Man-Made Arsenic Disaster in Bangladesh and Sustainable Solution to the Problem" organised by the Geology Department of Dhaka University (DU) at its auditorium. 

DU Pro Vice-Chancellor Prof Dr AFM Yusuf Haider also addressed the seminar, which was presided over by Chairman of the Department Prof Dr Kamrul Hasan.

The Pro-VC urged the scientists to work more for a sustainable solution of arsenic problem, as the problem has become alarming in Bangladesh.

He said Bangladesh is a disaster-hit country. Natural disasters and man-made disasters hit the country frequently. Arsenic is one of the man-made disasters, he added.

He further said most of the country's crops and industrial production depend on the underground water, but approximately 10 million tube-wells are affected by arsenic across the country.He also said more than 30 million people of the country are drinking the arsenic contaminated water. 

He urged the scientists to conduct researches to develop the solution of arsenic problem with a view to save the people from the curse of arsenic.

Source: The New Nation, June 01, 2008 

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City's groundwater level falls

As reported in the media quoting a recent study, the ground water level in Dhaka is dipping because of a massive extraction. Posing serious threat of land subsidence experts warn, the groundwater level is declining by up to three metres every year. The extraction caused a sharp drop leading to two cones of depression in water level and the upper parts of the aquifer are dewatered throughout the area, except for swathes of northeast and southeast corners, says the study that was carried out jointly by experts and academics.

How fast the dewatering process deep under the surface worked due to the massive extraction of water from underground is revealed by the study that says about 4.1 crore cubic metres of the aquifer dewatered until 1988, which increased to 227.2 crore cubic metres in 2002. The groundwater level was declining at an alarming rate and dewatering was spreading to the adjoining areas too. Dewatering widened by as much as 55 times in 20 years and experts stressed increasing the use of surface water to cut pressure on groundwater. According to the information of the Dhaka Water Supply and Sewerage Authority, upto 180 crore litres of water is pumped out in Dhaka and Narayangonj every day though the demand for water in both the places is much higher for meeting the daily requirements.

Meanwhile, the use of surface water has begun and under a plan it has been decided to use 100 crore litres surface water a day by 2015 with a view to reducing the pressure on groundwater as its level has been dropping alarmingly. There are about 2,000 deep tubewells operating in the capital - 800 out of them with WASA-approval. About 85 per cent of the WASA's water comes from underground sources and the remaining 15 per cent from surface water.

Source: The New Nation, June 12, 2008

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Making better uses of rain water
Sifat MunimTanin

Rain water is a free source of nearly pure water. It can be used to supply potable (drinkable) water and non-potable water. For non-potable uses, like watering landscapes, it is ready for use as it falls from the sky. For potable uses, rain water must be treated to remove or kill disease organisms that may be present.

This process in one form or another - has been in practice for thousands of years. According to Paul Woods of Texas A & M University, extensive water harvesting systems in the Negev Deserts of Israel more than 2,000 years ago have been documented. Additionally, Roman villas and cities were planned in such a way to take advantage of rainwater for drinking and air-conditioning. Cisterns, containers to collect rainwater, were fairly common in the United States in rural areas until the 1920s.

In Bangladesh the amount of rainfall varies both spatially and temporally. While the maximum amount of average annual rainfall occurs in the northeastern districts (55 cm) of Sylhet and Moulivibazar, the minimum amount falls in the western/southwestern districts (15 cm) of Meherpur, Kushtia, Chuadanga, Chapai Nawabganj, Noagaon, and Rajshahi. Also, rainfall is mainly restricted during the months of April to September. Consequently, rainwater harvesting will be relatively easier during certain months of the year in the certain parts of Bangladesh. Groundwater contamination by arsenic is more severe in the western/southwestern districts, where rainwater harvesting would be more appropriate to solve the polluted drinking water problems. A 1982 study, by the United Nations Environment Program, showed that with an average rainfall of 72 inches and using 1,100-gallon storage tanks, enough water could be collected in 12 hours to serve a family of six for 45 days.

Rainwater collected in various parts of the USA contains (in milligrams per liter): Fe (0.015) , Ca (0.075-1.41), Mg (0.027-1.2), Na (0.22-9.4), Ca (0.075-1.41), K (0.072-0.11), HCO3 (4-7), SO4 0.7-7.6), Cl (0.22-17), NO2 (0.02), NO3 (0.02-0.62), and Total Dissolved Solids 8.2-38), and pH of 4.9 to 6.4. On the other hand, Bangladesh does not have such industrial establishment like other developed countries. Rainwater in rural areas - away from atmospheric and industrial pollution - is fairly clean except for some dissolved gases, it may pick up while traveling through the atmosphere.

But there are some specific problem for Bangladesh. First, there is no enough land for the development reservoir in Bangladesh. Second, reservoir may become polluted by surface runoff. It may carry different pollutant from non-point sources. Possible non-point sources of contamination include fertilizer, pesticides, chicken and cow manure, dissolved minerals, sediments, sewage, decaying plants, algae, bacteria, aerosol fallout, and detergents. Fourth, ponds may be connected to groundwater flow and may subject to contaminated by dissolved chemicals. 

Now the supply of water is going to become a great problem in our country. We need to take proper initiative for the development of rain water harvesting process in Bangladesh.

Source: The New Nation, June 13, 2008

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