According to urban planner, Dr. Md. Shakil Akter (in a personal interview on 16 November 2019), some key causes of water-logging are: “1. Unplanned urbanization, 2. Lack of synchronization of the service organization, 3. dysfunctionality of existing services, 4. untimely waste disposal, 5. inadequate drainage system, 6. illicit encroachment of khals, 7. lack of waterbodies, 8. unsystematic construction, and 9. obstruction of khal networks.” By taking his points, the study provides an analysis of factors behind water-logging.
3.1 Urbanization, Encroachment and Disappearance of Natural Drainage System:
Dhaka’s natural drainage systems are disappearing. This disappearance is one of the primary causes behind the water-logging. Overpopulation and rapid development of new residential areas, illicit land filling, encroachments on lakes, and clogged drains due to ill-managed garbage and solid waste are some of the reasons behind the disappearance.
During 1960’s, around 50 khals crisscrossed Dhaka City, with the total length of 256 km, but gradual encroachment reduced the number to 26 khals, with only 125km total length (Tawhid, 2004). Dholai khal, which used to be one of the principle river-route in oldest part of Dhaka, now almost disappeared due to four decades of wrong policies (Huq and Alam, 2003). Excavated by the Mughal Subedar Islam Khan in 1610, this khal had interconnected outlets to the Buriganga, the Balu, the Sitalakkhya, and the Turag rivers (Banglapedia, 2015). Unplanned and irregular road constructions over the canal killed its flow, rendering it to extinction. Dhaka’s other khals faced similar fate. According to Mowla and Islam (2013):
“Segunbagicha Khal extending from Shahbagh to the Jirani Khal via the Manda Bridge… Begunbari Khal extending from Dhanmondi Lake to Trimuhani via Rampura before emptying into the Balu River, the Ibrahimpur canal, the Khathalbagan-Rajarbagh canal, the Gopibagh canal together with other minor canals of the city are all victims” (p.24).
Dhaka requires at-least 20 retention ponds, sizing Hatirjheel to tackle the storm water run-offs (Bangladesh news, 2009 July). On the contrary, around 1,000 ponds have now been destroyed in last few decades (Bangladesh news, 2009 March). Due to illegal encroachment, five rivers surrounding Dhaka including Sitalakkhya and Buriganga lost 324 hectares (Mowla and Islam, 2013). This is a gross violation of the Wetland Protection Act, 2000. Chowdhooree (2010) claims, with the current rate of loss, all of Dhaka’s temporary wetlands will disappear by 2031. Situation worsened to such a level that even if the Water Body Conservation Act, 2000 is implemented, the wetland loss cannot be stopped (Sultana, 2007). According to Sultana (2007), due to rapid population growth, Dhaka’s fringe areas are developing in ‘S’ shape, indicating the early stage of urbanization. The danger of such curve development is the disappearance of more wetlands, as the gradual population and economic activities growth means continuous filling up of more wetlands.
Owing to the real state and residential purpose land filling, vast water catchments in Aftabnagar, Badda, Baunia, Meradia, Banashree, Ashulia, Meradia and Amin Bazar areas are dangerously shrinking. These are areas marked as flood flow zones in the Dhaka Metropolitan Development Plan (DMDP), and land development in this zone clearly violates the Wetland Conservation Act, 2000. The rise of impervious surface in these wastelands increased the water-logging hazard that now regularly swamp Dhaka city during the monsoon.
The Dhaka Tribune reporter Anik (2019, July) informs that approximately 3,483 acres (1,410 hectares) of water bodies, low-lying lands filled up over the last nine years.
Table 5: Dhaka's Total and Filled Up Waterbodies (Anik, 2019)
Areas of water bodies and low-lying land filled up in Dhaka City
|
Type
|
Total Land (Hectares)
|
Filled Land
(Hectares)
|
Percentage of Land Filled in
|
Flood Flow Zone
|
760
|
436
|
57%
|
Water Retention Area
|
1,826
|
628
|
34%
|
Waterbodies
|
1,280
|
344
|
27%
|
Total
|
3,867
|
1,410
|
36%
|
Areas of water bodies and low-lying land filled up in RAJUK areas
|
Flood Flow Zone
|
30,230
|
7,730
|
25%
|
Water Retention Area
|
2,238
|
789
|
35%
|
Waterbodies
|
8,380
|
603
|
7%
|
Total
|
40,848
|
912
|
22%
|
3.2 Low Road and Area Elevation:
Dhaka WASA identified at least 48 water-logging prone areas (Shafiq, 2018). Though poor drainage and sewerage contributes to the waterlogging in many areas, some of these areas fall in low elevation pockets surrounded by comparatively higher grounds. Bashundhara, Mirpur’s Kazipara, Senpara, few pockets in Basabo, Khilgaon, Meradia, Shantinagar, Badda, Postagola, Demra, Amlapara, Siddheswari and parts of the old town fall in such category. Unable to pass through the sewage and drains, rainfall run-off flows down to these areas and create water-logging. During the personal interview, Dhaka Ward-14 Counsellor Humayun Rashid Jonny informed that, “Water drains from high elevation areas to low elevation areas. Senpara, Kazipara and Shewrapa (Mirpur) get waterlogged by water from Mirpur 10, 11 and 12. There is no place for rain-water to drain. For example- before there were khals and many ditches. The parliament has lake, so water drains there but our area does not have any water retention space.”
Another problem is the low elevations of the internal/community roads than the connecting main roads. Rain-water flows to this area and creates water-logging. The bad drainage systems do not help the situation and sometimes stuck rainfall water remains for 3-4 days. During Focused Group Discussions in Kazipara (Mirpur), Moulobhirtek (Khilgaon), and Basabo (Sabujbag) thana (sub-district) areas, the participants made similar complains.
3.3 Poor drainage and infrastructure system:
Due to obstruction, degradation, and demolition of natural drainage systems, Dhaka is prone to frequent flooding. A Detailed Area Plan (DAP, 2007) was developed to address the issue. However, rather than focusing on adequate space for water retention ponds and permeable surfaces like- parks and other unpaved surfaces, DAP focus is on roads and structures, pump stations and embankments approach. This approach risks intensifying residents suffering rather than diminishing them. The geo-morphology of Dhaka city indicates that a reservoir-based gravity drainage system will work better than pump and embankment-based flood control strategy. For instance, Dhanmodi area is encircled by water basin. As a result, this area is less susceptible to flood and waterlogging. On the other hand, Amlapara or BUET campus or Siddheswari area more susceptible to flood and waterlogging for the same reason that there is no place for the water to flow to.
According to an official of DNCC, Dhaka norths’ waste and storm water flows to the nearby Turag river. Following flow diagram and details obtained from DNCC show how the system works:
The picture above gives an idea of water flow and the detail is given below-
- Household connection and open space: still water created by either rain or everyday usage is known as householding connection and open space water. Household water or outdoor water first go towards the drains.
- DNCC’s open saucer drains and pipe sewerage: it is usually built while building the roads on both sides of footpaths. Household or rain water come through the pipes and fall into these drains. Though these drains the water pass to the DWASA-controlled khals.
- DWASA pipe sewerage and khals: it indicates the khals that are situated in Dhaka city. Water run through pipes or directly into these khals. Through these khals water to go different water bodies or holdings where water is removed through pump.
- Pumping station: in the pumping station water is dumped into the river.
In this process water passes from household or open space to drains to the river as the last step and this is the current and only water channel system. However, the system functions only theoretically. FGD in Kazipara, Mirpur (a DNCC area) reveals that, narrow drain-pipes, clogged and filled drainage system by solid waste, garbage, sands, and road side constructions materials, lack of alternative drainage, and poor sewage connections to the khals and big rivers are some of the key reasons behind water-logging. FGD participants also ranted out against concerned authorities poor drain construction:
“If rain continues for an hour and half or two, water-logging happens in the area. Drainage construction work that takes place here, are extremely poor in quality. For instance, manhole covers which are basically cement slabs broke within two days after their construction.”
When asked about the problems, the DNCC Executive Engineer (Zone-4), Mollah Md. Nuruzzaman replied,
“DNCC does not specifically work on waterlogging. However, it helps eradicate the waterlogging effect. For example, DNCC built sewerage for a better drainage system but it also works to reduce waterlogging.”
He blamed DWASA’s inadequate sewerage system, narrow drainage line, encroachments in khals and retention ponds, dumping of bricks, sands, cements and other materials in the water bodies, reduction of depth of Turag river for water-logging. Among other reasons mentioned by him are summarized in the below points:
Low powered pumps: Existing pumps are of very low power, thereby they pump out inadequate amount of rainwater.
Solid waste, garbage and encroachment: Owing to the residential development activities, retention ponds and khals connected to the pumps have become subject to land and solid waste filling.
Pumps do not operate when needed: When rain starts, water from all direction starts flowing towards the pumping station area, but pumping does not start at the same time. It starts after the water is full. It does not pump out as per the rate water is flowing in the adjacent area. The result is waterlogging. Poor management or negligence of the employees are the reasons behind this.
Ignorance: According to the DNCC engineer, “people are extremely ignorant.” They throw all types of wastes into the drains. They slaughter animals (such as cows) beside the drains as a result bloods flow to the drain; they do not even wash it with water. They throw other parts of the slaughtered into the drains. Construction works also contribute towards blocking of drains. Waste materials from the constructions like broken bricks, sand, cements, etc. are dumped in the drains.
Lack of maintenance: Maintenance is not done where needed. It has been seen that where a drain has become unusable, instead of repairing it, a new one is built over or beside the old one. It does not solve the problem but increases the cost. If old drains are repaired, it would cost less because it is less costly to maintain than building a new one.
Lack of synchronization: The organizations that work in the city, do it separately without any integration. This is another primary reason of waterlogging in Dhaka city. DWASA works on khals in their own way, BWDB on waterbodies or pumping stations or retention ponds in their own way, and city corporation works on drains in their own way. No one communicates with others even though all these works are interconnected. If there is a problem in any place, the entire water flow channel gets affected. For example- if DWASA builds a new khal or works on an old one and does not connect it to the drains, the water from the drains will not flow to the khals properly. On the other hand, if BWDB’s work is not synchronized with DWASA then water will not flow from khals to the pumping stations.
Pucca (solid/pitch/permanent) road: previously roads were not pucca and there were plenty of open spaces. Rain-water could easily go underground. But now everything is Pucca so water cannot go underground.
In another interview, BUET Professor Shah Jahan Mandal gave similar opinion regarding the pump’s functionality and capacity, lack synchronization among authorities and lack of awareness among Dhaka residents. He added (summarized below):
- Drainage system do not properly work. Although the pumping stations located at Kallyanpur, Dholaikhal, and Goranchanbari are functional, but the drainage system linked to these facilities leading to the river are not adequate and often not operational.
- Box Culverts do not properly function, because of deep design flaws. Most of these culverts are shaped in a rectangular format, but they should have been designed in UCEP format.
- Sewerage systems are not properly cleaned and maintained. In fact, Bangladesh do not have the necessary tools and machineries to properly maintain the sewerage system.
Unplanned road construction and real estate expansion, inept urban planning, lack of garbage and solid waste management resulting in blockage of Dhaka drainage system.
A recent DSCC and Dhaka WASA joint report found several waterlogging chokepoints in the Dhaka South (Shafiq, 2018). According to the report rainwater from Dhanmondi-8/A Staff Quarters intersection, Dhanmondi-27, Kathal Bagan, Rapa Plaza, Gastro Liver lane, Green Road, Kalabagan Dolphin Lane, Meradia, and Madartek, traverse through the Panthapath Box Culvert, Rampura and Hatirjheel canal, and finally come to pass in the Balu River. Rainwater drain into the Buriganga River through the Buriganga sluice gate from Kazi Alauddin Road, Nazimuddin Road, Hossaini Dalan, New Market, BGB gates 3 and 4, Chawkbazar, west-south Bottola, Lalbagh, and Bangsal. Rainwater from Mouchak, Malibagh, Shantinagar, Motijheel, Dilkusha, Bailey Road, Siddheswari, Circuit House Road, Doinik Bangla, Segunbagicha, Paltan, Shantibagh, Fakirapul Rajarbagh, and Arambagh end up to the Buriganga and Balu Rivers through the Kamalapur Pump, Segunbagicha Box Culvert, Maniknagar canal, Manda canal, and Jirani canal. In Gulistan, there is no drainage, triggering waterlogging Bangabhaban and Secretariat areas after rainfall. Water from Mugda, Basabo and Khilgaon passes through the Madartek, and Basabo, and Trimohoni khals, eventually reaching the Balu and Buriganga rivers. Rainwater from Laxmibazar, Kaptan Bazar, and Agamasi Lane flows through the English Road, Dholaikhal box culvert, ending up at the Sutrapur pump. Rainwater from Postogola, Jurain, Muradpur, Kodomtola, Shyampur, and Doyaganj rail-bridge drains through the Zia Sarani canal, Rosulbagh, and Shimrail pump (Water Development Board), draining into the Shitalakshya river. In Mir Hajaribagh, there is no drainage.
Similar to the Kazipara (a DNCC area) FGD findings, the FGDs in Khilgaon and Bashabo- Sabujbagh areas (DSCC areas) reveal that the narrow drain-pipes, clogged and filled drainage system owing to solid waste and garbage dumping, poor sewage connections to the khals and big rivers as the key reasons behind water-logging. In addition, FGD participants pointed their figure at corruption, lack of coordination and ignorance among the concerned authorities, dumping and littering by ignorant people, ignorance in drain cleaning as the primary causes behind water-logging.
3.4 Waste Management System:
Dhaka’s haphazard waste management is one of the core reasons behind this city’s water-logging. Unprecedented urban congestion, incredible population density, explosive population growth, and unchecked urban migration have made it impossible to clean the drains and streets as fast as the waste thrown onto them. With a density of 47,400 people per square kilometer, Dhaka tops the world’s most densely populated city list (Dermographia World Urban Areas, 2018). According to Kazi (2002), this City daily generates daily 3500-4000 tons solid waste, making the per capita generation about 0.5 kg. In 2016-17, the total waste generated was approximately 8,52,390 tonnes (Khan, 2019). During the rainy season, the amount of waste generation increases, as this is the time when most of the seasonal vegetables and fruits become available into the market (Tawhid, 2019). The left-over of fruits, trashed food, plants and grass, brick, paper, dirt and polythene materials make up majority of Dhaka’s waste.
Management of this massive waste primarily lies on the two city corporations—the Dhaka North City Corporation (DNCC) and the Dhaka South City Corporation (DSCC). DSCC’s waste dumping ground Matuail Landfill, with an area 40-hectare -- already has 20-meter-high piles of garbage, while DNCC’s 21-hectare Aminbazar landfill -- is already nine-meter-high (Khan, 2019). Both city corporations are unable to process the waste using the traditional landfill method. With recent donor support, they have taken several projects such as community-based waste management activities, urban public and environmental health development projects, medical waste recycling plant development of sanitary landfill, and waste-based power plant (Khan, 2019; Ahmed, 2019; Chandan, 2019). But Mahmud (2018) reports that the managements have seen no major improvement due to following reasons:
- flouting rules and regulations: Negligence complaints, in duty against DNCC and DSCC staffs and sweepers are common. Although, nearly 4,000 tons of daily household garbage generates in Dhaka, the DNCC and DSCC only report 500 tons or less. Such disparity clearly indicates that citizens complain is not irrelevant. Citizens also do not follow rules, many dump garbage ignoring designated spots and waste bins.
- unsuccessful mini-bin project: In 2016, Dhaka’s city corporations installed 6,000 waste bins. Lack of strict waste disposal law and Carelessness among Citizen’s led the project to go with fiasco. People throw garbage here and there, instead of the bin. In fact, many bins got stolen.
- incomplete STS projects: Lack of coordination and blame games are common among the concerned authorities. For instance, DSCC and DNCC officials blame RAJUK’s faulty plan for not being able to build secondary transfer stations (STS) in every ward for efficient waste management. In 2013, World Bank funded the STS project. The project missed the December 2015 deadline. According to the officials, lack of free space, illegal occupation in the allotted spot, and interreference by the influential people for the delay and incompletion. As of February 2018, in DNCC, among 72 STS only 51 have been finished, while in DSCC, only 12 among 45 have been finished. Such procrastination and blaming do not help, as unmanaged wastes quickly block the drainage and sewerage systems.
- no steps to tackle the construction dumps: Both city corporations lack strict regulations against irregular construction material dumping in footpaths and roads. Unchecked and unprotected open construction and demolition of old buildings, random road excavation and repair often lead to congestion in the drainage system.
- open garbage trucks: Mobile garbage removal directives are often not properly followed. Garbage truck drivers and cleaners are supposed to cover the waste when moving them to the landfill from the STS. But most often the truck tops remain open and wastes randomly fall in the roads. Rainfall washes away these dropped wastes to the nearby drains and sewerage systems.
- fund crisis for waste-based power plants: DNCC and DSCC’s flagship project the ‘waste-based power station’ never took off. The original construction deadline was 2013, but as of today, Italy-based Management Environment Finance SRL Ltd failed to disburse the funds needed initiate the project.
- failed 3R waste management: In 2012, Bangladesh Climate Trust Change Fund provided USD 2.47 million to The Department of Environment, which prescribed the 3R method- reduce, reuse, recycle. Inadequate sensitization among public and repeated poor waste management rendered the project failed.
- inadequate waste treatment plant: Matual and Aminbazar landfills produce substantial leachate and have been polluting the nearby environment. Among the two landfills, only Matuail has a leachate treatment plant, but it is insufficient against the heavy load of waste. Leachate, a liquid that drains or leaches from a landfill, is hazardous to arable lands, water resources and aquatic lives.
Among the solid waste, most dangerous is plastic and polythene. The government took initiatives to ban regular use of polythene in 2002. The ban’s effect did not last long. After a short recess polythene again become available in the market. Cheap and readily available, most people like to reuse polyethene bags. One of the many hazards of polythene and plastic is that careless littering of these items blocks drainage systems. A recent report published by Earth Day Network (2018) ranked Bangladesh as world’s 10th most plastic polluting countries. The estimated contribution of plastic is eight percent of the country's total annual waste, of which around 200,000 tonnes go into the ocean and rivers (Seppo, 2018). According to former city mayor Mohammad Hanif, “Indiscriminate dumping of polythene bags has been creating serious environmental hazards and water logging because this insoluble object is choking the drainage system and causing overflow of filthy sewerage water” (Islam, 1998).