2012 World Water Day – why good quality water still matters to Bangladesh
By Peter Ravenscroft
Bangladesh, 22 March 2012: Bangladesh has no shortage of water, but it faces the age-old dilemmas of balancing too much and too little water, flood and drought.
What then of the future? Bangladesh faces the problems of increasing population and living standards. The demand for food is increasing. Urban areas are growing and occupying productive land. Waste flows are increasing, polluting land and water. Climate change, through rising sea levels, takes away land for agriculture and habitation and is changing the seasonal pattern of rainfall and river flows.
Bangladeshi famers were masters of adaption long before any climate scientist told them what the word means. Farming systems have always been adapted to variable supplies of water.
How does water affect food security?
Water affects food security in four ways: Excess (flooding that is too early or too late); Deficit (drought and declining levels); Competition; Water quality. There are two main water quality threats: salinity and arsenic.
Salinity: changing livelihoods
In many of the coastal parts of these areas, shallow groundwater is brackish and therefore unsuitable for irrigation, and deep groundwater, where it is fresh, is unofficially preserved for potable use.
Exploiting deep groundwater is therefore controversial; however, either deep or shallow aquifers could be supplemented by recharging either aquifer with treated surface water in an agricultural area or at the points of highest vulnerability, such as Khulna City. The resource exists but the technique has not been tried except at a micro-scale for community drinking water supply.
Arsenic: tackling through traditional methods and innovation
• Crop breeding, by traditional or GM methods, to produce cultivars that suffer reduced yield loss and/or take up less arsenic in the edible parts of the crop;
• Growing new rice varieties that need less water, so adding less arsenic to the soil and freeing water for use by others; although little is known about their practical potential, iron-rich soil amendments or inter-growth of hyper-accumulating ferns could reduce the impact of arsenic in irrigation water. In extreme cases, soil can be rehabilitated by stripping off topsoil and selling it for brickmaking.
Although threats to the quantity and quality of water used for food production are increasing, initiatives are in hand which, if successfully scaled up, could go a long way to ensuring the security of food supplies in Bangladesh.
This article is adapted from a speech given in Dhaka on World Water Day by Peter Ravenscroft, Water and Sanitation Specialist at UNICEF Bangladesh.