Dhaka’s Monsoon Woes

Dhaka’s Monsoon Woes

Faizul Khan Tanim researches the ever-increasing problems caused by monsoon each year and looks for possible solutions

Monsoon is believed to be a season of blessing in agriculture based Bangladesh. But nowadays, in both urban and rural parts, it is simultaneously considered a miracle and a menace, due to the negligence of the government, utility organizations and citizens’ commitment.

With monsoon approaching, Dhaka residents are already worried about water logging due to the poor drainage system of the city.

The season has not started properly, yet floods set off by monsoon rains out of the capital have killed six people, displaced more than 10,000 and washed away shrimp farms close to the Bay of Bengal when the region’s Matamuhuri and Bakhkhali Rivers overflowed after several days of heavy rain, inundating almost 200 villages and destroying paddy fields.

Studies from urban planning departments of universities, water modelling centres, flood and water management institutes reveal that the major reasons for rain induced flooding also known as monsoon flooding, in Dhaka and other major cities are – encroachment of major canals, unplanned urbanisation, mass migration in the city from villages due to decreasing job opportunities, increase in built-up areas and metal roads, filling of low-lying areas to construct buildings with no or little provision for drainage, the main drainage systems of the urban area (khals) blocked by unauthorised constructions, deficient sewerage system, insufficient storm sewers constructed in the extensions to the urban area, lack of maintenance to the system, lack of co-ordination among the different utility organisations engaged in the development works who dig in different times during monsoon making large holes on city streets, solid waste disposal in the storm sewer and more.

Dhaka metropolitan area borders with four rivers - Buriganga, Turag, Balu and the Tongi Khal (canal). Some of them are so polluted that the surface water is little short of toxic.

A study on the drainage in Dhaka city conducted by Ole Mark, Terry van Kalken, K Rabbi and Jesper Kjelds of Danish Hydraulic Institute and Surface Water Modelling Centre Bangladesh revealed that Dhaka is protected from these rivers flooding by an encircling embankment. Most of the time during the monsoon, the water level in the river remains higher than the terrain inside the city area. This implies that the city drainage depends very much on the water levels of the peripheral river systems. Hence, standard draining by gravity may not always be possible. In order to facilitate and improve drainage it is considered to install drainage pumps at some of the flood control and drainage structures connecting to the rivers.

Therefore, when proper monsoon starts, not only might Dhaka experience water logging like previous years (which already started in West Bengal due to heavy downpour) in this already power, gas and other regular commodity starved city, there might be water-borne diseases caused by flood and severe fresh-water crisis.

If this happens at a time when only few days are left for Ramadan to start, not only are the residents already upset with soaring prices of food and commodity, it will be quite a chaos for all.

M Mozzammel Hoque, professor, institute of water and flood management (IWFM) of Bangladesh University of engineering and technology (BUET), said “During monsoon when there is extreme rainfall, both the surface water level of the rivers and the ground water table rises as they become saturated absorbing all the rain water. This means, during this period, river water levels generally remain higher than the internal drainage level. This is when the excess water flows to the lower regions and if that water cannot be drained out, water stagnation occurs”.

“Our drainage facility is insufficient and also due to low maintenance of the existing system, calamities like rain induced flood occur. And this is when we need to use hydraulic structures like sluice gates and pumps to force out the excess water towards the rivers. The embankments should play a part so that water from rivers does not slide in to the city. We should divide Dhaka in to zones according to areas and develop the drainage systems to connect to the four rivers bordering Dhaka”, Hoque added.

The Dhaka water supply and sewerage authority (WASA) are saying that they are implementing plans to cut down water logging problems by evicting illegal structures on different canals of the city.

WASA sources said that cleaning of drainage pipes in Dhaka has to start immediately otherwise monsoon floods will be inevitable.

It must be mentioned that failing to clean up regularly, the sewer lines have waste piling up to a point that it has started to seep out through the manhole covers in different points of the city already. The streets not only experience stench but health and hygiene hazards as well.

In previous years, with a recorded 45 millimetres heavy rainfall in the city, it overflowed sewerage lines in many areas caused serious water logging, otherwise called monsoon flooding, with roads and alleys of Gulshan, Banani, Tejgaon, Malibagh, Mouchak, Paltan, Shantinagar and some low areas dipping under five to six inches of water.

Now as soon as monsoon flooding takes place, few scenarios arise. In case of even a mild shower, many areas get completely submerged and as such it becomes difficult for the vehicles to move, thanks to the ever-increasing numbers of pot holes and absence of manhole covers.

The low-income group people living close to the streets and pedestrians usually get the worst of it. Transportation becomes scarce and utilising this sordid situation, the drivers/helpers demand much higher fare.

Speaking to a highly placed WASA official, requesting anonymity the officer said, “And why won't there be problems? The sewerage system covers only one third, which is 30 percent of Dhaka’s area, meaning the remaining two-thirds still use the septic tank to remove toilet waste. The number of canals in place to deal with sewage is now down to 29 or 30, from the 42 installed during British era. The part of Dhaka inside the flood protection embankment area, 136 km long, is the only part served by the WASA sewerage network or the WASA drainage system. Uttara recently got in that network”.

“However, the situation is not as grave as people think it is. After a heavy downpour, if the manhole covers are kept open for sometime, the stagnant water will clear within two to three hours after the rain stops. Now, one cannot only blame the WASA drainage system and the City Corporation in charge of the surface drain system because as residents it is our duty to use civic sense as well. The reason of the drainage system blockage is caused by the haphazard dumping of non-biodegradable waste like polythene, snacks and other rubbish items which clog the arteries and veins of the system. Our men, when sent down a manhole, retrieve these trashes to start with. How can this be justified?” the officer added.

WASA authority admitted that sewerage and drainage in Dhaka is highly inadequate. 70 percent of the city is not connected with WASA and it is not surprising when there are approximately 300,000 main water connections, as opposed to only 60,000 main sewerage connections in the city.

When asked about the short term and long term solutions to address this issue of inadequate sewerage system, the WASA official said we need to keep the existing canals clean and need to retrieve the ones encroached immediately and the City Corporation has to regularly clean the surface drains as short term plans. For long term, we need to protect these canals and areas around them from further abuse by the large organizations, NGOs and corporate sectors. Here, the local residents of each area have to play a part as it is their area and they must develop their civic sense and stop random littering.

WASA officials said that to speed up the cleaning procedure, a more co-ordinated approach should be taken between the Dhaka City Corporation (DCC) and them. They said that the random diggings of utility organisations is due to the delay of normal procedures, decisions from high levels and sudden realisations of having to finish the budgeted fund hastily for development; otherwise fresh roll up of finance for the next year will not see light.

*This article was first published in The Independent's Weekend Magazine July 29 2011 - www.theindependentbd.com