Water aplenty but not a drop to drink

Nothing could be more appropriate than 'Nature for Water' as a theme for this year's World Water Day. The reference here is to return back to Nature for the prevailing crisis of water all across the globe. In reality man has tinkered with Nature so much that its backlash is inescapable. Yet there is no guarantee that the fiddling or meddling with Nature's way will stop where it has reached today. Such engineering goes on at the national and global level without consideration for long-term effects.

Land filling at the backwater of the Florida coast by the Bush administration for housing was found to be responsible for hurricane Irma wreaking havoc in Florida last year. Earlier hurricane Katrina also did the same. The Farakka Barrage has had a most ominous impact on the river Padma and many of its and the Ganges' tributaries. Then at a local level, land filling in water retention and floodplain areas together with encroachment of the rivers around this capital city along with extreme pollution of their waters has led to a critical water crisis for the city people.

How critical the situation is yet to be fully assessed but it definitely portends a most grim scenario. Extraction of groundwater has been causing decline of the water table by more than a metre each year in the city. With little or no scope for replenishing the groundwater, the water table has gone down well below the acceptable limit. Even a moderate earthquake, if it occurs, can end up causing more damage and destruction than it would have done if the water level did not fall so low. If such a natural disaster spares the city, it has no room to feel at ease. Its water crisis is likely to reach a point, say 30 to 50 years from now, that people will be forced to desert this city. A few other cities will also find themselves in similar situation at some point or other in the future.

If severe water crisis stares in the face of the cities, it is no better in the rural areas. Worldwide, humans can use only one per cent of the water and 97 per cent is saline water; the rest 2.0 per cent stays in the form of ice. Usable water does not necessarily mean its potable variety. A study carried in 40 upazilas in Bangladesh by the NGO Forum for Public Health presents an alarming picture of water quality of tube-wells. As high as 62 per cent of tube-wells' water is in moderate to high degree of danger. Here arsenic contamination has been left out of reckoning. Presence of heavy metals like manganese and lead, beside bacteria, has been found in tube-well water in those upazilas.

The reason why water is becoming scarce and increasingly contaminated is the excessive extraction of groundwater for irrigation. Due to excessive lifting of underground water in a wide swathe of the country, the water table declines by one to three metres each year and thus falls below the level of the Bay of Bengal. This leads to slow but sure intrusion of saline water. Even rain and flood waters fail to replenish the extracted water. So tube-well water is increasingly becoming unsafe for drinking.

Availability of water is becoming limited, drinking water only more so. The threat is posed both to cities and countryside alike. Even where surface water is abundantly available, it is no guarantee that it can be used safely. Chemical fertiliser and pesticide are getting accumulated in water bodies with flows only during the monsoon. The dams built to protect vast areas from flooding may have kept water at bay by diverting water through channels other than natural, but at the same time the topographical change has invited dangers of varied nature. One of the main problems is the absence of annual flooding and the deposition of alluvial sediments. Also natural fish breeding has been terribly hampered. In its place the stagnant water within the boundary areas get increasingly contaminated by fertiliser and pesticide washed away by rains and the little water allowed to run through sluice gates.

Getting back to Nature is thus becoming a formidable challenge. The greenhouse gas responsible for global warming shows no sign of decreasing. Its impacts are already felt the world over. With Bangladesh finding itself more at its receiving end, if the situation deteriorates at the rate it does now, not only will the country's agriculture be seriously affected but usable water will also be critically in short supply.

How to meet the challenge then? Irrigation technology has to be improved where less water will be required for the purpose. For example, a simple technique of plastic bottle with holes developed and used by farmers in some areas has done away with two-thirds or more water used previously for irrigation.

Unfortunately, the technique is not known all over the country because of lack of its promotion. A vigorous campaign for its promotion is well in order. If one third of the current level of water is used for irrigation, it may be replenished by rain water. Dependence on chemical fertiliser and pesticide may also be reduced in favour of organic farming. This will help water to retain its original quality. Only then it may be treated for safe human consumption.

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