WATER POLLUTION AND SCARCITY 3.2.1 INTRODUCTION and bioaccumulation of harmful substances in the water-dependent food chain can occur. A variation Water is the most vital element among the natural of inland surface water quality is noticed due to resources, and is crucial for the survival of all living seasonal variation of river flow, operation of organisms. The environment, economic growth and industrial units and use of agrochemicals. Overall, development of Bangladesh are all highly influenced inland surface water quality in the monsoon season by water - its regional and seasonal availability, and is within tolerable limit with respect to the standard the quality of surface and groundwater. Spatial and set by the Department of Environment (DoE). seasonal availability of surface and groundwater is However, quality degrades in the dry season. The highly responsive to the monsoon climate and salinity intrusion in the Southwest region and physiography of the country. Availability also depends pollution problems in industrial areas are significant. on upstream withdrawal for consumptive and non- In particular, water quality around Dhaka is so poor consumptive uses. In terms of quality, the surface that water from the surrounding rivers can no longer water of the country is unprotected from untreated be considered as a source of water supply for human industrial effluents and municipal wastewater, runoff consumption. pollution from chemical fertilizers and pesticides, and oil and lube spillage in the coastal area from the The largest use of water is made for irrigation. Besides operation of sea and river ports. Water quality also agriculture, some other uses are for domestic and depends on effluent types and discharge quantity from municipal water supply, industry, fishery, forestry and different type of industries, types of agrochemicals navigation. In addition, water is of fundamental used in agriculture, and seasonal water flow and importance for ecology and the wider environment. dilution capability by the river system. Water stress occurs when the demand for water exceeds the amount available during a certain period Bangladesh is the lower riparian of three major or when poor quality restricts its use. This frequently river systems, the Ganges-Padma, the occurs in areas with low rainfall and high population Brahmaputra-Jamuna and the Meghna (GBM), and density or in areas where agricultural land or industrial constitutes about 8 per cent of the combined activities are intense. Even where sufficient long-term catchment area. Over 92 per cent of the annual freshwater resources do exist, seasonal or annual runoff generated in the GBM catchment areas flows variations in the availability of freshwater may at through Bangladesh (Coleman, 1969). The times cause water quality degradation (EEA, 1999). combined flow of the Ganges and Brahmaputra typically vary between less than 5000 m3/s in the The Water Pollution and Scarcity section of the report driest period (March-April) to 80,000-140,000 m3/s deals with inland surface and groundwater quality, in late August to ear ly September (WARPO, pollution problems, salinity attributed to low water 2000b). flow and coastal water pollution. Other water-related environmental problems have been discussed in detail The contribution of local rainfall to the annual surface in other sections. For example, droughts and floods runoff is about 25 per cent, with significant seasonal have been discussed under the Natural Disaster section. variation. Annual rainfall and evapotranspiration of The Biodiversity section addresses the implications of the country show that there is a substantial excess of shrinking dry season water area. Riverbank erosion and rainfall everywhere in the monsoon season. From the the consequences of gradual silt deposition in the annual overall averages, dependable rainfall exceeds floodplain are discussed under Land Degradation. evapotranspiration by over 10 per cent in most parts of the country, except in the Northwest (NW) and 3.2.2 PRESSURES Southwest (SW) regions. In the NW region, rainfall and evapotranspiration are almost equal, but in the For water resource analysis and planning, water SW the overall deficit is about 10 per cent. From demands have been categorized into consumptive and November to May, evapotranspiration exceeds rainfall non-consumptive uses. Consumptive demands are all over the country, except in the Northeast (NE) those where water is lost from the resource pool and region (WARPO, 1999b). non-consumptive demands are those where used water The concerns over water quality relate not just to the is returned to the resource pool, and can be re-used water itself, but also to the danger of diffusion of (WARPO, 1999b). The consumptive use of water is toxic substances into other ecosystems. The aquatic increasing due to the growth of different economic environment for living organisms can be affected sectors - agriculture in particular. 41 BANGLADESH : STATE OF THE ENVIRONMENT 2001 The increasing urbanization and industrialization of in Bangladesh for areas that were once inundated Bangladesh have negative implications for water facing water scarcity in the dry season. Dry season quality. The pollution from industrial and urban water availability depends on water use for irrigation, waste effluents, and from agrochemicals in some dry season rainfall and withdrawal or diversion of water bodies and rivers have reached alarming water upstream. It has implications for navigation, and levels. The long-term effects of this water the wetland ecosystem and its productivity. contamination by organic and inorganic substances, many of them toxic, are incalculable. The mar ine Excess water in the monsoon causes floods and and aquatic ecosystems are affected, and the riverbank erosion, which res ult in loss of land and chemicals that enter the food chain have public people being left homeless. This is discussed in detail in health implications. the Land Degradation and Natural Disaster sec tions. Although there is an abundance of water in the Water quality in the coastal area of Bangladesh is monsoon, often the water quality is compromised degraded by the intrusion of saline water that has during floods, and this translates into a type of water occurred due to lean flow in the dry season. This scarcity when good potable water becomes difficult to affects agriculture significantly, as well as other obtain. consumptive uses of the water. The inter-linkage of pressures, state, impacts and A common phenomenon in the lower riparian various policy responses to address water related countries is that of enough water in monsoon, but environmental problems have been presented in water scarcity during the dry season. It is also common Table 3.2.1. Detailed analyses of various policies and Table 3.2.1 Inter-linkage of pressures, state, impacts, and various responses related to water Pressures State Impacts Policy Responses Pollution · Decreasing inland water · Pressure on urban water · Environmental Conservation · Industrial effluent quality in dry season source Act and Regulation · Agrochemical · Decreasing coastal water · Fish fingerling mortality, · Setup environmental quality · Fecal Pollution quality migration and quality of fish standard · Ship breaking and lube oil · Salinity intrusion in · Degradation of fish habitat · Industrial EIA and effluent discharge surface and groundwater · Yield reduction (soil fertility treatment plants to reduce pollutants load · Oil and lube spillage · Soil salinity increase loss) during normal refueling of · No primary or secondary · Increase in risk from · Polluters pay principle ships at sea and river ports measurement is available waterborne diseases · National Water Policy: EIA for · Low water flow in the river on discharge quantity · Affecting marine aquatic life water development projects system in dry season and increase surface water flow in dry season Scarcity (dry season) · Decline river water level · Decline in aquatic resources · National Water Policy: · Upstream withdrawal for and discharge production Dredging and water harvesting, consumptive and non- · Low water flow · Navigation problem regional cooperation, consumptive use · Shrinking dry season · Increase conflict among augmentation of dry season · Low rainfall water area different users and sectors flow and use of surface water for irrigation · Gradual siltation in river · Decline/fluctuation of · Domestic uses bed and floodplain groundwater · Increase pressure on · Dry season irrigation · Less access to safe groundwater · Flood drinking water · Quality of water decline Abundance of Water · Increase flooding · Crop yield reduction and · National Water Policy: (Monsoon season) · Increase water related damage Structural and non-structural · Geographical location and hazards · Disruption of livelihood mitigation (early warning and setting (92 per cent runoff · Increase river bank system flood proofing) flows through Bangladesh, erosion · Damage of homestead and · Planned development among which is 7 percent of the towns different sectors need catchment area) · Increasing river bank · Population displacement · Monsoon Climate (78 per shifting cent rainfall occurs in the monsoon) Source: SoE Study Team 42 WATER POLLUTION AND SCARCITY programs to address degradation of water quality and scarcity are presented in section 3.2.4. 3.2.2.1 Causes of Water Pollution The major causes of degradation of inland water quality are related to land based activities, when adequate regulatory