But sub-optimal use of these irrigation devices and unplanned cropping activities have resulted in low irrigation coverage.
SIMPLE WATER LIFING DEVICES MANUAL
According to a recent survey, water is being lifted in this country through 26,704 deep tubewells, 4,69,226 shallow tubewells, 56,829 low lift pumps, 1,42,132 manual pumps, and more than 5,65,000 indigenous water lifting devices. In Bangladesh, about 94% of the irrigated land is under small and minor irrigation. With proper utilization and management, 4.5-5.0 million ha of land can be irrigated by using groundwater. This indicates that additional 3.68 million ha of rainfed lands can be covered with irrigation. At present only about 3.12 million ha have been brought under irrigation. But according to the present estimate of available water resources, only about 6.8 million ha can be irrigated. In Bangladesh, 7.56 million ha are suitable for irrigation. Irrigation devices specially designed mechanical appliances used for lifting water either from surface or sub-surface sources for irrigation and domestic purposes. Since high yielding varieties of rice are very susceptible to drought, these need very frequent irrigation. In Bangladesh there has been widespread use of both shallow and deep tube wells for irrigation of agricultural lands, particularly during the dry period (November to March). In modern times, pumps have facilitated the use of underground as well as surface water. However, the use of canals, dams, weirs, and reservoirs for the distribution, control, and storage of water was probably initiated in ancient Egypt. Estimates of total irrigated land in the world range from 543 to 618 million acres, almost half of them in India, Bangladesh, Pakistan, and China.
It is also used in wetter areas to grow certain crops, such as rice. Irrigation has been practiced for thousands of years, chiefly in regions with annual rainfall of less than 500 mm, including many countries of Africa, Asia and America. Irrigation artificial water supply for dry agricultural land by means of dams, barrages, channels, or other devices.
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