Bangladesh is a deltaic land created and flushed by numerous rivers. It had 1400 to 1500 rivers in the 11th century, which was reduced to 7 to 8 hundred due to various natural anthropogenic factors over time. Presently, no more than 400 rivers with numerous tributaries and distributaries are existent in the country, out of which 25 rivers are already dead or moribund. Dozens of others are drying up gradually. Only around 100 rivers have adequate navigable depths round the year at the moment. The total river route in the country in 1971 was 24,140 km, covering 8 percent of the country's area, which has now been reduced to 3800 km only during the lean flow period.
There are three principal river systems in the country: (a) Barak-Meghna; (b) Brahmaputra-Jamuna; and (c) Ganga-Padma. Teesta is an important water flow for the country because it is the terminal tributary for the Brahmaputra. These systems and all other rivers carry an annual water load of about 1074 billion cubic meters (bcm) from the upstream sources. Rainfall adds another 251 bcm of water volume. Around 150 bcm of water is required to be available in the riverbeds to maintain navigability.
Bangladesh is historically a country of riverine agro-economy. This small land is burdened with an increasing populations. Over time agriculture is going to lose the position as highest contributor to the GDP. There has been a gradual shifting of its economy towards industrialisation and other drivers of economic prosperity. The country's population and eco-insensitive industrial development are now the major factors behind river degradations through grabbing/cordon structures as well as pollution of the rivers.
River degradation through physical contaminants
Physical Degradations: These are manifested by reduced flow, siltation, erosion, cordon structures and encroachment. Any exotic entity in the river water is itself a polluter.
Reduction of flows: Flow reduction becomes critical in 97 percent of the rivers in the dry season (November to March). Causes of flow reduction include: flow diversion and water withdrawal in the upstream region mainly by India in all 54 rivers, and partly by China and Myanmar, through damming or other obstructive or diversionary infrastructures. Indian River Linking Project (IRLP) and Tipaimukh Dam will be last nails in the coffin. Dried up water flows is provocative to more polluting interference in water contents.
Silt deposition: Prolonged silt deposition meanwhile killed 187 rivers (28 percent of the rivers). The rivers of Bangladesh carry about 3.8 billion tonnes of silt every year and 40-45 million tonnes get deposited on the river beds. Many rivers have lost their depths and about 77 percent of the river-mouths are silted. Silt deposit rate has increased in 574 rivers (i.e. 86 percent). Reduced water flows from upstream are a prominent causative factor in more siltation and consequent impacts like river bed elevation, reduced water holding capacity and more river bank erosion.
River Bank Erosion: 41 percent of rivers in Bangladesh suffer from erosion. During the rainy season, erosion increases in some rivers due to raised river beds and reduced water holding capacity and that causes further erosion during the next monsoon.
Cordon Structures: Around 500 flood control, drainage and irrigation projects, undertaken around the last 60 years, have disconnected 35 million hectors of land from the rivers. Harmful structures like regulators or sluice gates and cross dams were built on many rivers causing immense negative impacts. Cross dams and short length bridges made in the name of development are now the main river-killers in the country. There is cause to worry that the recent governmental initiative “Bangladesh Delta Plan 2100” is going to be the replica of the same.
Encroachment: 158 rivers lost their width from unauthorised encroachments and this process is quite unhindered due to strong socio-political links of a section of grabbers.
Instrumental and organic dumping: Different abandoned parts of marine vehicles like wooden boats, steamers, fishing nets, boundaries used in dry seasons for fishing traps, plastics and other non-degradable items, household materials, rejected foods-fruits-vegetables etc. are also causing further pollutions.
Untreated hospital wastes: Hospital waste and highly poisonous and infective materials are getting mixed with water all over the country throughout the year, contributing to a severe biological pollution of rivers and wetlands.
Reduced quality of water, more sediments, narrowing, cordoning, diversions, dry ups, commercialisation, so called development projects, unplanned re-excavations, sluggish flows due to the reasons mentioned above accelerate pollution and induce deaths of rivers.
Chemical contamination: Threat to public health
About 11 percent of the rivers in Bangladesh are polluted by industrial wastes. Further escalations are noted from agro-chemicals, marine vehicular discharges and wastes and municipal and domestic wastes. As per a governmental study, rivers around Dhaka, namely the Buriganga, Shitalakshya, Turag, Balu, Bangshi and Dhaleswary, have earned notorious reputations due to very high level of pollutions from industrial wastes (60 percent), and municipal/household drainage of toilet wastes (30 percent). We have heard a former state minister of water resources in the late 90's say that a ten feet thick poly bags layer had caused “carpeting” on the Buriganga river bed! The newly built Hatirjheel project is still pouring its dirty wastes into river Balu through the Narai khal without proper treatment. Especially during the winter season, all these rivers become absolutely filthy and poisonous; devoid of oxygen and aquatic biodiversity. The government seems quite incapable or shy in executing the decisions for mandatory ETP fixation in the industrial plants.
Excreta play a significant role in polluting the rivers in Bangladesh. In spite of prolonged national drives, we are yet to achieve a satisfactory sanitation management system. Rivers and canals are major disposal receptacles for human and animal excreta as well as dead animal bodies, especially by riverside inhabitants. Media sources revealed a few years back that the number of small hanging latrines on both sides of the Karnaphuli was about 1.5 lakhs. It is not a stretch of imagination to say that the rivers and water bodies are considered as the drains in Bangladesh.
About 1.6 million tonnes of chemical fertilisers and 4-5 thousand tonnes of pesticides are used for agriculture every year. Though illegal worldwide, 9 out of 12 Persistent Organic Pollutants (POPs), also known as the dirty dozen, are also being used all over the country for agricultural and household purposes. These are smuggled-in items proven harmful to human health, namely: Eldrin, Dieldrin, Chlordane, DDT, Endrin, Heptachlor, Mirax and Toxafen etc. A huge portion of these dangerous items are carried by rain water and flood, contaminating the rivers, wetlands, ponds, soil and finally entering the food chain, causing numerous deadly diseases including cancers.
Marine vehicular discharges: This chemical contamination results in obnoxious chemical pollution in river-water and gets deposited on river beds. Amount of such category is said to be 1.7 to 2.4 billion tonnes, causing 35 million tonnes of silt deposits in the rivers, every year.
Trans-boundary mixed pollution
Trans-boundary river pollution is also a significant factor for Bangladesh. All the plain land and hilly rivers are carrying huge amount of wastes from a big stretch of India surrounding Bangladesh and a part of Myanmar. The components include eroded river bank soil, peeled off hilly stones, boulders, construction materials from urban developmental projects and hydro-power plants and dam constructions, contaminated mountains and glaciers, run off urban wastes, coal dust, gravels sandy flood, suspected radioactive materials, and municipal wastes from Meghalaya, Assam, Tripura, West Bengal and bordering Myanmar. Bangladeshi rivers work as the gate way to enormous amounts of waste from the upstream region. This problem can only be solved through trans-boundary planning and cooperation.
Health impacts of chemical pollutants of rivers
Chemical pollutants of water induce toxic impacts on all the living entities including human beings through water, soil and even air. Common diseases from the polluted rivers are: skin allergy and inflammations, gastroenteritis, typhoid and paratyphoid, liver diseases like hepatitis, jaundice, upper respiratory inflammations, and any of these areas may develop even deadlier cancers. The population around the river banks is, in a true sense, a permanently vulnerable society, with higher morbidity and mortality rates, prolonged sickness, having less work capacity and costly lives leading to more poverty.
World Bank and government study performed by IWM
In general, we know that Dhaka Water and Sewerage Authority (WASA) has a limited capacity (around 30 percent) of managing toilet discharges and the rest goes to the rivers around Dhaka city through the WASA storm water drainage but without formal permission from the organisation. Side by side, the Dhaka City Corporation (DCC) has the capacity of disposing 45 percent of the municipal wastes. The rest remain lying in or around roadside bins; often find their way back into households through footwear and add to the the cyclic human family disease process. A notable amount flows into the rivers through the roadside drains. There was a governmental study by the IWM in 2007 on the pollutions in the water courses around Dhaka namely: Buriganga, Shitalakshya, Turag, Balu, Bangshi, Dhaleswari and Tongi Khal. The study correctly revealed that 60 percent pollution is caused by the industries, 30 percent by WASA and DCC and the rest by others. This study, in addition to other matters, dealt with the biological pollutions of the rivers around Dhaka city.
Key points on findings from the biological part of the study “Comparative Disease prevalence between watershed (6 rivers around the city of Dhaka) and Control Populations (riverside Tangail town)” reveals:
1. There is strong co-relation between disease and river pollutions.
2. Industrial pollution is widespread and easily affects drinking water.
3. Health care cost of pollution represents 21.5 percent of annual income in Hazaribag area.
4. Jaundice, skin diseases and diarrhoea are very high in watershed areas.
5. Men and children are more affected in watershed areas.
6. Men are more affected by jaundice than women.
7.Infants in control area are less affected by jaundice and diarrhoea.
8. There is co-relation between jaundice and diarrhoea in watershed areas.
9. Major source of water contamination is from piped supply.
10. Productivity loss of polluted land is estimated to be 40 percent.
11. Vegetable cultivation in river beds is severely damaged by polluted water.
12. There is no fishing activity in dry season in rivers and canals in greater Dhaka.
13. In rainy season, some fish appear here with insignificant reduction in amount but there is a notable number of declining species.
14. The rice-vegetable-fish reduction in the river basin areas is affecting nutrition.
15. Widespread contamination has caused scarcity of safe surface water sources in Bangladesh, except few natural springs in hilly areas.
16. According to IWM, water is so polluted at the intake point that it can't be treated to become safe for drinking.
17. Rivers around Dhaka are at the height of contamination, not only in dry season, but also posing high threat of health calamities.
Core essence of river pollution and degradation: wrong approach towards lifeline
Historically and traditionally, men have wanted to conquer rivers by cordoning them with long embankments, dams, barrages, crossroads, short-span bridges and culverts. People consider rivers as drains and throw all their wastes and garbage into it. This is done not only by individuals but also by corporations and governments. Bangladesh is no exception. But currently the choice for this commercial approach towards the rivers is taking the reverse course worldwide, and sensible people are adopting an ecological approach towards rivers. Science, conscience, awareness and a sense of justice is the way of success to stop the atrocities and pollution of our rivers.
River pollution is violating the people's right to safe water and liveable environment. Rivers are not pipelines, these are our lifelines. We must protect the rivers!
The writer is General Secretary, Bangladesh Poribesh Andolon (BAPA;) Coordinator, Jatyo Nadi Rakkha Andolon, Email: email@example.com