Addressing water-logging issue needs priority attention

---

Shahiduzaman Khan
Heavy rains disrupted this year's Eid-ul Fitr congregations throughout the country. Due to strong presence of monsoon wind, heavy rains swept the city with full intensity, paralysing life. Roads and low-lying areas of the capital were inundated and got water-logged. Many city dwellers could not move out from their houses to exchange Eid pleasantries due to water-logging problem on the streets. Traffic congestion was not, however, acute due to lean traffic on the roads.
The heavy rainfall again exposed the vulnerability of the city's drainage system in spite of the authorities' repeated claim of its substantial improvement over the years. In fact, water logging remains a perennial problem for the city since the eighties. Major parts of the city get flooded for hours even after a short spell of heavy rains making movement of traffic impossible.
Indeed, inadequate and faulty drainage network, filling up of drainage canals and lack of proper cleaning of drains are the main reasons behind water logging in the capital. The drainage system was not upgraded keeping pace with the rapid urbanisation while around 50 per cent canals in the city dried up or have been illegally filled in and occupied over the last two decades causing water logging in many parts of the city during the rainy season. The city's present catchments to retain rainwater have either been blocked or encroached upon in absence of strong monitoring system. The retention capacity of the water bodies has also been reduced due to lack of re-excavation work.
According to a study by a group of environmentalists, pumping out of rain water was designed through the eastern bypass, which is yet to work properly. It also detected that the major portion of the lone retention pond of the western part in Goran-Chandbari has also been illegally occupied. The drains constructed by Water and Sewerage Authority (WASA) could pass 40 per cent of the water while the city needs natural drainage to pass the rest 60 per cent rainwater.
Reports say roads were constructed in Rayerbazar, Rajabazar, Gopibagh and Shyampur Kadamtala by filling up canals and constructing storm water and sewerage lines. Width of Segunbagicha canal, Dholai Khal, Debdholai Khal and Paribagh canal has been narrowed down for building box culverts. The water under the culverts remains clogged due to lack of maintenance. The Dhaka WASA had earlier moved to recover 26 out of 43 canals from encroachers. But, the move yielded no tangible result. Besides, once the recovery drive is over, many canals again get choked up or encroached due to lack of excavation, proper demarcation and monitoring.
The Dhaka WASA had 135 km drainage line in 1990, which is now 265 km but the population in the capital has gone up to 12 million from that of 6.84 million in 1991. In many places where there is no drainage system of WASA, the DCC covers the area by pipe drains or surface drains. The WASA is responsible mainly for maintaining the city's drainage system cleaning them once in a year but most of the time 50 percent of the drains remain clogged mainly due to lack of cleaning.
Experts say construction of box culverts was also a wrong plan, as the passages under these culverts are not cleaned leaving them choked up round the year resulting in water stagnation. WASA has two permanent pump stations at Dholai Khal, and Kallyanpur while Bangladesh Water Development Board (BWDB) runs another pump house at Goran Chatbari in Mirpur. Yet these pump stations are too inadequate to pump out the stagnant rain water. Due to lack of coordination between the WASA and the Dhaka City Corporation (DCC), the drainage management system suffers immensely worsening the water logging in the city. Most parts of Uttara, Gulshan, Banani, Badda, Manda, and large sections of Khilgaon, Bashabo and Rampura are still outside the WASA's drainage system coverage. In places where there is no drainage network of the Dhaka WASA, the DCC covers the area with drainage pipes.
A committee, formed to prepare national drainage guidelines during the tenure of four-party alliance government, in a meeting suggested bringing all the drainage lines of the DCC under the Dhaka WASA as it is the custodian of the drainage system. However, no initiatives were taken by the successive governments to bring the drainage lines under one umbrella. Eighty percent of the canals and water bodies, the major means for water to recede, have been filled up during the last two decades. This has increased pressure on the whole drainage system in the capital.
While it is necessary to monitor the city's drainage system all round the year, unfortunately Dhaka WASA has not developed such a system as yet. In developing countries, electronic sensors are used for monitoring the drainage system of large cities. However, since setting up of such system in Dhaka is costly, experts have suggested forming a team to monitor the rainwater drainage lines round the year and forming of another team to clean them.
In order to effectively deal with the city's water-logging problem, its natural drainage must be fully restored. Only decades ago, Dhaka could be protected from flooding and water logging by its numerous canals. The city had then a smaller population. But unplanned expansion of the city to allow a much bigger population to live in it, has taken its toll now. Only a well-planned drainage system could rid Dhaka of these perennial problems.
szkhan@thefinancialexpress-bd.com