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Water crisis: Pitfalls and possibilities

Tanwir Nawaz
DHAKA city is facing an acute water crisis. This happens in the summer months due to the high demand for water and the growing population. This year the situation is worse due to shortage of electricity, which affects the pumping of under-
ground water. The situation might improve marginally with the coming of the monsoon, but will resurface again next year.
Dhaka has a population of nearly 14 million. Its minimum consumption demand is over 2,200 million liters at only 157 liters per person per day (as against the daily normal requirement of
around 400 liters per day in a metropolitan area). Dhaka Wasa is unable to meet even this modest demand. Further, there is a system loss of nearly 40%.
At full capacity, Wasa is able to produce maximum of 1,750 million liters per day with some 427 deep underground tube wells. The Saidabad Water Treatment Plant (SWTP) is capable of supplying 225 million liters per day. The rest of the water supply comes from some 700 privately sanctioned deep tube -wells of much lesser capacities.
There is a normal shortfall of at least 250 million to 300 million liters per day. The Wasa tube-wells depend on generators when the power supply fails. However, there are only 220 back up power generators available for the 427 pumps. So, nearly 50% pumps have no back up power supply available.
The 427 deep tube-wells are sunk to a depth varying between 200 feet in the fringe areas to 500 feet in the inner areas, while some have been sunk to a depth in excess of 1,000 feet. In one case the depth is close to 4,000 feet. The water level in Dhaka, particularly in the central part, has been falling every year by 1.5 to 2.5 meters, and some tubewells will run dry in the near future, causing further shortfalls. Will this cause future land subsidence problems also?
With the filling of some 43 canals and many water bodies in Dhaka, there is very little ground water recharge. This requires going deeper and deeper for any new wells. The underground water
sources could be exhausted in the not too distant future. A problem in underground water supply is the potential contamination by lateral migration of toxic contaminants from the surrounding rivers and the emergence of arsenic.
The problem facing Dhaka Wasa is that the demand for water is increasing at the rate of some 7% to 10% per year because of population growth and more industrial uses of water. Dhaka's population will double to more than 24 million by 2024. Even at current low rate of consumption (around 150 liters per head per day) Dhaka will need more than 3,700 million liters by then.
It is highly unlikely that the ad-hoc deep tube-wells or the underground aquifers will be able to supply or sustain this level of demand. So, the crisis can only get worse. The main future potential source thus has to be surface water from surrounding rivers. But how good is the condition of the surrounding river waters?
What is the solution to our water supply problem? It cannot be the endless supply of underground water through deep tube-wells, buthas to be surface water. As noted earlier, the SWTP currently supplies 225 million litters of water from the river Sitalakhya. Three more phases, each with 225 million liters, remain unrealised to date.
It took fifteen years of various trials and tribulations to build one surface water treatment plant. We will need to
» tuodcJ iGnoiinmofni build fifteen such plants of the same size during the next twenty years just to maintain the supply at current levels, if underground water supply was to cease. But Sitalykhya is polluted and has limited potential as a surface water source.
The waters of Balu and Turag and Buriganga are extremely polluted and chemically contaminated through industrial waste dumping. So the hunt for surface water has to be from Meghna in the east to Jamuna in the west to Padma in the southeast. In addition to the cost of plant construction there will be the cost of bringing the water to the treatment plants and connecting them to the distribution system.
Bringing water from downstream Padma will be even more costly as it will involve, in addition to pipe lines, the cost of large pumping stations and of operating them continuously. Clean water cannot be drawn from the confluence of Sitalykha and Meghna as Sitalykha is already contaminated. Meghna is also undergoing similar misuse and industrial contamination.
The third option is to bring water from Jamuna through excavation of deep canals from somewhere near Nagarpur and connecting it to Dhaleswari and subsequently to Turag and Buriganga.
The water will have to be drawn before it reaches Turag, which is contaminated. The water can then be sup-
fine "igU •
plied to new treatment plants or piped to Saidabad where additional plants can be built.
One note of caution, if we continue to pollute all our rivers, particularly with chemical and industrial wastes, our sources of safe surface water will also vanish. We should be particularly careful where we dump effluents from the industries.
With unregulated industrial expansion and waste dumping we will definitely pay an extreme price. In the short run, we may opt for a combination of underground water supply and surface water treatment plants. However, in the mid to longer-term, surface water will have to be the major solution to our water supply problems.
Since it will take time to construct the new plants, we are well advised to start without delay. If we are unable to finance these from the public treasury, we should consider a combination of public private partnership. In some cases it could be through build operate and transfer projects (BOT).
If we cannot afford to build the plants and the pipelines ourselves then let somebody else build the plants and sell the water to us under controlled and agreed price set-ups. But this is one sector we can neglect only at our own extreme peril.
Tanwir Nawaz is an architect and urbanist He was the Co-Chairperson of 2001 and 2003 Task Force Reports on Urban Governance prepared by CPD (Centre for Policy Dialogue) E-mail tanwir nawaz@yahoo com