Irrigation in Upper India.

By H. G. MCKINNEY, M. E., Assoc. M. Inst. C. E., District Engineer, Harbours and Rivers Dept., and late of the Irrigation Dept., India.

[Read before the Royal Society of N.S. W., 7 November, 1883.]

As the subject of irrigation is admitted to be one of great and growing importance to this Colony, and as it has lately been attracting much notice, the time appears opportune for calling attention to the systems of irrigation adopted in India, where irrigation works are unrivalled in extent and unsurpassed in their management. In an essay such as this it is impossible to give more than a mere outline of such a wide subject. It will be my endeavour, therefore, to convey a fair general idea of the principles on which the works are designed, of the scale on which they are carried out, and of the arrangements adopted in the distribution of the water.

The irrigation systems may be classed under three heads:-1st, irrigation from wells; 2nd, tank or reservoir irrigation; and 3rd, irrigation from canals. The first system has been practised from the earliest times of which there is any record. Under it wells are sunk in such situations as command the levels of the field to be irrigated, and the water when raised to the surface of the ground flows off to the field in channels made for the purpose. The method of raising the water differs in different localities, and according to the depth at which the water is met with. In Lower Bengal and in Oudh, an earthen vessel suspended from the end of a balancebeam is a common arrangement for this purpose. In the Northwest Provinces, the cultivators generally use a leather bag, in which the water is raised by means of bullocks walking down a slope. In the Punjab the Persian wheel is almost universally adopted. This contrivance bears some resemblance to a whim of very rude construction, but instead of a winding drum and an alternate lifting arrangement, continuous motion is given to a wheel fixed over the well, and on which is an endless rope, laden with an earthen waterpot on each round, thus supplying a constant stream. Comparisons have been made of the work done by these primitive methods and their modifications, but such comparisons are of little practical use. The depth at which water is found, the area to be irrigated, and the means of the cultivator, are the first consideration s

actually taken into account in settling the arrangement for lifting the water. As a general rule, where the supply has not to be lifted more than 5 feet, baling is resorted to; but beyond this, for small, medium, and great depths, the balance beam, the leather bag, and the Persian wheel respectively are used.

The cost of well irrigation is very difficult to estimate. It is generally arrived at in statistics by reckoning at current rates the time of the men and bullocks employed. As a matter of fact, this does not represent the actual cost to the great proportion of the cultivators, as the labour required is very often present and available in their households. The cost of irrigating by any of the three methods last mentioned is, on an average, about three times greater than the rates charged by Government for irrigation from the canals. Tank or reservoir irrigation is comparatively little practised in the Bengal Presidency, on account of the country being particularly suitable for irrigation from canals. Water from jheels or swamps is, however, utilized for irrigation wherever available, baling being generally resorted to for raising it to such a height as will command the land adjoining. It is sometimes assumed that two men, baling with a palm-leaf basket, will raise 2,500 cubic feet of water to a height of 5 feet in one day; that is, 2,000 gallons will be raised 5 feet for very little over three farthings, at the usual rate of wages for such work in India. I tested the progress made in one case by actual measurement, and found that two men lifted 5,000 cubic feet of water to a height of 8 feet in one day.

It is chiefly with canal irrigation that this paper is intended to deal. Any account of such irrigation would be incomplete without a brief description of the nature of the country, and of the peculiarities of the rivers from which the water is obtained. The immense fertile alluvial plains of Upper India, intersected as they are at intervals by snow-fed rivers, probably afford a grander field for irrigation on scientific principles than any other country in the world. The Bengal Presidency may be considered as two great deltas or doabs, or rather two great series of doabs, the one series extending from west to east along the courses of the Ganges and its tributaries, and the other extending from north to south in the course of the Indus and its tributaries. The courses of the Ganges and Indus and their tributaries, after leaving the hills, are very similar in their general characteristics. The country through which they flow is, to all appearance, a perfectly flat plain, the surface of which is generally from 30 to 60 feet above the level of the river. In every case there is a strip of low-lying land on one or both sides of the river, a large proportion of this land being liable to inundation. The rivers follow very tortuous courses through this low land, or "khadir” as it is termed, and their courses are more or less altered in every monsoon. The variations