Dhaka’s coming water crisis

Friday, April 8th, 2011


Rafiqul Islam


The World Water Day-2011 was observed all over the world on March 22 focusing on the theme “Water for Cities: Responding to the Urban Challenge.” Water is an essential part of survival lives. At present around 200 crore people have been facing a great challenge to access to safe and drinking water around the world. About 40 percent of people have no access to safe drinking water in developing countries, particularly in African and Asian countries.


The water crisis will be triggered in coming years while acute water crisis will be erupted in urban areas due to rapid growth of population and urbanisation and lack of civic amenities. But, the demand of water is increasing day by day keeping pace with growth of population and development of civilisation. Bangladesh will also have to face acute water crisis in coming decades.


There are different water gaps in Dhaka city caused by rapid urbanisation; these are – growth of informal settlements; water demand and supply; service coverage; consumption pattern and water safety.


The rapid and uneven urbanization has resulted in growth of informal settlements; inter-city and intra-city gaps in water supply coverage. About 35 percent slum dwellers of Dhaka city in living in only 4 percent of land area while the hygienic sanitation in slums is only 12 percent at the moment. Piped water coverage in Dhaka is 83 percent, Chittagong 41 percent, Khulna 45 percent and 102 municipal towns 40 percent.


The gap is wide in consumption pattern as from about 20 litres per capita-day in low income slums to about 400 litres per capita-day are provided in high income areas. The downstream people are the sufferers as the upstream people discharge the pollutants into the rivers.


Almost 90 percent of water supply comes from underground water and Dhaka continues to withdraw groundwater for its 85 percent of supply. According to the international standard, there should be no color in the effluent discharge. Thermal waste has become a major concern for us. The Shitalakhya River, one of the main rivers surrounding Dhaka, has become subject to thermal waste.


This sort of waste destroys the ecosystem of rivers which has happened to Shitalakhya. The actual hygienic sanitation coverage is quiet below than that reported by the government. This is because an essential requisite for hygienic sanitation is proper sewage treatment which is missing in our sewerage system.


The country’s only sewage treatment plant Pagla Sewage Treatment Plant covers only 7 percent of the Dhaka’s sewerage network (covering only 20 percent of Dhaka). Sewerage system in the rest of the country refers mainly (45-50 percent) to the septic tanks, half of which are also not properly designed.


Although Bangladesh is rich in water resource, but there remains lack of safe water. The cities in Bangladesh are the centre of employment, communications and development. So, people are rapidly migrating in these cities from rural areas place putting additional pressure on the infrastructure and water resources.


Drinking water management in these cities are facing challenges. The water bodies have been becoming extinct due to rapid urbanisation and pressure on infrastructure, which destroying city’s ecosystem.


As a consequence of repeated building of urban infrastructures the rainwater can no more refill the groundwater reservoirs. The water supply management in the cities is dependant on the far-reaching ground sources or surface water sources. This is making the water supply management more expensive and technically complex in cities.


Due to different geophysical characteristics, the challenges of water supply in different towns and cities are also different accordingly. The quality of water sources are deteriorating due to various man-made and natural causes that is increasing the threats of our water, environment and biodiversity.


Random destruction of water sources


About 65 percent of the surface of Metro Dhaka was water bodies (Ponds, small lakes and steams) about 20 years ago. But, now we have seen very few number of water bodies in the city.


The underground and surface water in the city is contaminating in many ways. Industrial and household waste is destroying surface water in rivers surrounding the Dhaka city, which is the major concern for us.


Water percolates very slowly through these soils from the water bodies to recharge the ground water table. During the rainy season the water bodies around Dhaka were filled up and a significant quantity of surface water would also runoff into the streams and rivers.


Water from the filled up water bodies used to slowly percolate over time and recharge the groundwater, thus elevating the water table to a constant level every year until lately with introduction of massive land filling projects to build houses for an ever growing Dhaka population.


A significant portion of those water bodies was filled and so most of the rainwater escapes Dhaka through surface runoff, creating artificial flooding in many areas. Because of land filling surface water does not percolate and recharge the underground water.


Since the majority of water comes from underground water to address the demand of city dwellers, the underground water level is declining gradually. With more land filling and concretization of city, the rate of groundwater depletion would be worse in near future.


Surface water may address rising water demand in coming days


Since underground water is rapidly declining day by day in Dhaka city, surface water may address the rising water demands of city dwellers in the coming days. Water expert and eminent environmentalist Dr Ainun Nishat said that the use of surface water should be increased considering future demand.


“We are randomly using underground water without considering its quality. It is contaminated in many ways,” he said.


About the surface water reserve in rivers surrounding Dhaka city, he said although a huge amount of surface water is reserved in these rivers, the water of these rivers could not be treated due to uneven disposal of chemical and industrial wastes.


Dr Ainun Nishat, also vice chancellor of BRAC University, said that surface water treatment is a long term process and it will take time to treat the highly polluted water of the rivers.


He said the politicians never emphasise treating the surface water. “Since at least 4-5 years is needed to install a water treatment plant, they do not want to work in this regard. They want instant results.”


Referring to the water supply of Dhaka WASA, the former head of the IUCN in Dhaka suggested reshuffling the WASA pipe system to ensure safe and clean drinking water for city dwellers.


About people’s right to water, Dr Ainun Nishat said that access to safe drinking water is a human right, and so the government should work sincerely to ensure safe drinking water for all.

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