Is Sanir Akhra a dark foreboding of things to come?

One manifestation is the explosion of public discontent in the Demra (Sanir Akhra) area in the south-east part of Dhaka. The people of this area are apparently suffering from acute water supply shortages for the last three months. The frustration boiled over last week and the people came out on the streets in large numbers and barricaded the roads.

To contain the situation, the army came with water tanks to supply emergency water to the aggrieved people. This is an extremely short-term measure and cannot satisfy the people in the normal term. However, this difficult water supply situation will get bad in the short term and worse in the longer term.

To explain the matter, Dhaka Metropolitan Area has an estimated population today of 12.5 million. Its minimum consumption demand is over 2,000 million liters (at only 16 liters per person per day as against the daily normal requirement of around 40 liters per day).

Dhaka WASA, which has the responsibility of supplying piped water, is able to produce a maximum of 1,700 liters per day. For this it uses some 427 deep underground tube-wells. In addition, it has the Saidabad surface water treatment plant, capable of supplying 225 million liters per day and much smaller plants at Pagla. The rest of the water supply comes from some 700 privately sanctioned deep tube-wells of much lesser capacities.

There is thus a normal shortfall of at least 250 million to 300 million liters per day even at the low rate of consumption noted earlier. The 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, in case of power failure, nearly fifty percent of the pumps have no back-up power supply available. The 427 deep tube-wells used to draw the waters are sunk to a depth varying between 200 feet in the fringe areas to 500 feet in the inner city areas. However, some 36 tube-wells have been sunk to a depth in excess of 1,000 feet to draw water from deep aquifers. 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 between 1.0 and 1.5 meters and some tube wells will run dry. Will this cause future land subsidence also? With the filling of some 43 original canals and many water bodies in Dhaka city, there is very little ground-water recharge. This requires going deeper and deeper for any new wells. How long we can carry on drawing underground water this way is any body's guess. The underground water source is finite and could be exhausted in the not too distant future.

The problem facing Dhaka WASA is that the demand for water is increasing at the rate of some 7 to 10 per cent per year because of population growth and more industrial uses of water. Dhaka's population is increasing fast and will double to more than 24 million by 2024 at the latest.

Even at current low rate of consumption (15 liters per head per day ) Dhaka will need more than 3,700 million liters of water by that time. Even with best efforts 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, unless drastic and radical efforts are undertaken.

What is the solution? It cannot be the endless supply of underground water through deep tube-wells. The solution has to be surface water. Saidabad water treatment plant currently supplies 225 million liters of water from the river Sitalakhya. It took fifteen years of various trials and tribulations to build one surface water treatment plant We will need to build fifteen surface water treatment plants of the size of Saidabad during the next twenty years just to maintain the water supply at current supply levels, if underground water supply was to cease.

But the Sitalykhya is polluted and has limited potential as surface water source since its head has basically died. The waters of Balu and Turag and Buriganga are extremely polluted and chemically contaminated through industrial waste dumping. Through our neglect, greed, and misuse we have basically killed these rivers as source of safe surface water supply.

So the hunt for surface water is from far afield, from Mghna in the east to Jamuna in the west to Padma in the southeast. All of these will be costly. In addition to the cost of plant construction, there will be the cost of bringing the water to the treatment plants.

Bringing water from downstream Padma will be even more costly as it will involve, in addition to pipelines, the cost of large pumping stations and the cost of operating these pumping stations continuously.

Water cannot be drawn from the confluence of the Sitalykha and the Meghna as the Sitalykha is already contaminated. The Meghna is also undergoing similar misuse and degradation and industrial contamination. The third option is to bring water from the river Jamuna through excavation of water carrying deep canal from somewhere near Nagarpur and connecting it to the river Dhaleswari and subsequently to the Turag and Buriganga. The water will have to be drawn before it reaches the Turag, which is contaminated. The water can then be supplied to new treatment plants built at the northern part of the city 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 (like we have already killed the Buriganga), our sources of safe surface water will also vanish. We should be particularly careful where we dump effluents from the toxic leather industries. Uncontrolled industrial waste dumping is unconscionable. With unregulated industrial expansion and waste dumping we will definitely pay an extreme price.

While we cannot continue to depend on deep tube-wells indefinitely as the underground water supply dwindles, more and more existing tube-wells go out of commission, and the population continues to rise, we will only invite extreme peril if we choose to bury our heads in the soil and hope that things will somehow take care of themselves.

We may be able to somehow cope with Demra (Sanir Akhra) like situations today as the basics are still controllable in the short run. However, in five, ten, or fifteen years, when things will get out of control, we will be able to do absolutely nothing without action today.

To do that we need a few things. We need resolution, commitment, good planning and proper schemes for financing. Since the new plants will take time to plan and construct, we are well advised to start with out 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 entirely as BOT (build-operate-transfer projects). If we cannot afford to build the plants and the pipe lines ourselves, then let somebody else build the plants and sell the water to us under controlled and agreed price set-ups. But like many other vital urban sector issues this is one sector we can only neglect at our own extreme peril.

Tanwir Nawaz is an architect and urbanist.