At a time when climate change has posed the greatest threat of all to agriculture and scientists are at a loss how to face it, an innovative water storage system developed indigenously may be a cogent answer to both floods and droughts. Called bhu-garvashayan (recharging of water at the underground vacant level), the method is already in operation in crop fields belonging to farmers of Diar Kazipur in Natore. Floodwater and excessive rainwater have long proved a curse because those cause water-logging in many areas of Bangladesh, including in the capital city. The system developed by the North-Bengal Research Foundation and Development was successfully introduced in March this year.
The merit of this system is that it can store monsoon rainwater for use in lean season when a drought-prone area smarts under scorching heat. Similarly, excess amount of stagnated water from an area can be channelled into the vacant pockets underground in order to make lands suitable for cultivation. Even the saline water of coastal belts can thus be stored underground for irrigation in lean season. It can as well be used as normal drinking water. Reportedly, each underground storage has a capacity of absorbing knee-deep stagnated water from 10-12 acres of land during the monsoon and this can be lifted in high summer for irrigation of the same size of land.
Clearly, here is an appropriate technology for the condition of most parts of the country. The device can be rectangular or square with eight openings for water to get in. Then there is a pipe through which water flows after filtration down to the desired layer of the underground. During the monsoon when the rain is heavy all eight entry points are opened up to let water enter into the device and this is so regulated that only as much water is allowed to be removed as required from marshy lands. So the marshy lands close to the Natore village has no problem to get rid of the excess water that accumulates in the rainy season. Similarly, farmers there can lift water by pumps for irrigation when needed. Already farmers have started calling the box-like device a magic box because they are now free from the scourge of excessive rainwater and drought.
Apparently, the cost for setting up such a device at first look appears to be high. The total cost for construction of one such device is Tk 700,000. But if its service life is taken into consideration, it is certainly not much. If the device remains in operation for 30-35 years -and that too with nominal repair work, the cost comes to a negligible sum. There is no way to call it forbidding. For farmers of modest means though, managing the money at a time is an uphill task. But if a number of them contribute together, the task may be accomplished in private capacity. Better would be to manage soft loans for the purpose so that farmers can avail of the opportunity.
Now that the Natore experiment has become a stunning success, there is no doubt that this technology can be replicated in areas of similar character all across the country. Many of the wetlands remain under water throughout the year. This does not mean all of those have to be brought under cultivation. Some of the wetlands have been declared as bird or fish sanctuaries. Those must be left alone as before and if possible preserved even better in order to restore their original shape and size.
However there are still many swamps that give one crop a year. Those can be the right candidate for this technology. But the coastal areas that have remained water-logged for years following the two cyclones Sidr and Aila should be brought under a comprehensive scheme for cultivation. Thousands of people there have lost their lands and livelihoods on account of the intrusion of saline water and a sizeable number of them had to leave their homes and hearths for unknown destinations and alternative livelihoods.
Again, the water-logging in cities like Dhaka and Chattogram have become a perennial problem. Already the underground water table of Dhaka has fallen to a precarious level. If the technology can be used wisely here, this city may once again recover its normal underground water table.
The technology has proved its worth and may even be improved further. Its prospect can be unlimited. Surely it can revolutionise cultivation of crops on the one hand and also come as a blessing for retaining environmental health. Water extraction from underground has been so extensive that many fear an environmental disaster is waiting in the wing. Today shallow tube-wells are no longer usable for lifting water for irrigation. Arsenic invasion has rendered water of tube-wells unsafe for drinking. In a situation like this the rainwater and surface water stored underground by using the just invented technology will dissipate all the threats all at once.
The technology may be put to further tests in regions where cultivation is very difficult. Natore experiment has concentrated on marshy lands. If it is equally suitable for drought-prone areas, where rains are scarce but sparingly heavy, there is no doubt about its utility. Let's hope the technology make a difference in a big way for sustainable availability of water without harming environment.
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