Ordinary agricultural works in the Madras Presidency irrigate an area of about 3,365,157 acres, yielding a revenue of approximately Rs. 1,31,04,126. They consist of two kinds, viz. (1) rain-fed tanks or reservoirs, generally of minor individual importance, each deriving its supply directly from rainfall distributed over an area of land, which is called the catchment basin ; and (2) channels from rivers and streams providing direct irrigation, or supplying tanks, together with the tanks supplied. In tho first case, the rainfall is caught and retained before it reaches natural lines of any importance. In the last, it is diverted from the drainage lines while pursuing its course, and led away by arti ficial means. In connection with these last are the anicuts or weirs which have been constructed by former governments and under British rule. About 1876, there were in the Madras Presidency 1212 weirs across rivers or streams, 769 of which were in the three districts of Madura, Salem, and S. Arcot. There were 33,318 tanks and irriga tion canals, of which the districts of Coimbatore, Vizagapatam, Kistna, Kurnool, and Nelloro had only 2590. The irrigated area from all these 'was approximately 3,365,167 acres, and the revenue Rs. 1,31,04,126. Besides these, there were irriga tion works belonging to landlords, also others belonging to the Government irrigation systems, for which capital and revenue accounts are kept. Of these last, the principal are the anicuta or weirs across the rivers Godavery, Pennar, Cauvery, Vellar, Palar, and Tambrapurni, and the great reservoir of Chembrurnbakam.
It was Lord Canning's opinion that the con struction of great irrigation works might be en trusted to private companies; but the Madras Irrigation Company and E. I. Irrigation Company formed at that time (1861) for the Tumbudra and Mahanadi, have been pecuniarily unsuccess ful. For the Mahanadi river scheme, for instance, the capital raised in June 1861, nearly a million sterling, was intended to be utilized in certain initiatory parts, amounting to about one-half of the complete scheme, which was estimated at two million sterling. ,To meet the second half of the scheme a second million was to be raised when wanted, by a second issue of shares. The works began in December 1863. Irrigation was first available in December 1865, but was first taken up in April 1866, giving returns in October 1866. Navigation began to pay in March 1863, but eventually the scheme was bought up by Govern ment in December 1867. The initiatory half of the works was not then perfectly completed, but was nearly so. The estimates having been ex ceeded, the first issue of one million was very nearly spent. The navigation returns from March 1863 to August 1867 amounted to 15922. Tho cultivators refused to pay for the water. In the year 1872-73 the total acreage of irrigation was only 4753 acres, yielding £4263 in water rates, and the navigation returns on a tonnage of 154,422 tons amounted to £4750 ; the total receipts, in cluding £1481 from other sources, amounted to £10,293 for that year.
Mr. Latham, chief engineer of the Madras Canal and Irrigation Company, reported that the expectation, based upon the experience of the north-western canals, that irrigation would not fall off much after its value had once been felt during the famine, has proved delusive. Yet the
increase caused by the famine had been but moderate : before the famine),. . 13,923'45 acres.
1876-77 tho year of failure of rain), . 24,54508 „ 1877-78 a year of famine and late „ 1878-79 (a year of excessive rain), . . 14,731'49 „ The Tumbudra canals were led from a weir, 4500 feet long, across the rocky bed of the river at Sunkesala, and it was intended to reach 250,300 acres of rice cultivation up to the year 1865. The Madras Irrigation and Canal Company had realized less revenue than sufficed to cover the working expenses. Up to the end of 1877-78, the total outlay was Rs. 1,52,73,352. The attempt to make it suitable for navigation added Rs. 36,80,584 to its cost. The canal was designed to irrigate 200,000 acres of wet crops, or a corresponding area of other crops. But the largest area irrigated was in the famine year 1876-77, when it reached 82,477 acres, viz. wet crops 24,545, dry crops It is now recognised that canals for traffic must have the same width and depth from their commencement to their termination ;, but that irrigation canals, by giving off channels along their course, should gradually fine away to their end.
Between 1862-63 and 1872-73 the acreage irrigated by the Western Jnmna Canal was from 331,037 to 496,542 acres ; in the Eastern Jumna' Canal, from 160,355 to 274,101 acres ; the Bari Doab Canal, from 126,016 to 287,079 acres ; and the Ganges Canal, 205,605 to 1,078,399 acres.
In 1869, the Eastern Jumna Canal irrigated 102,322 acres; in 1877, 103,632 acres ; and in 1878 it was 110,722 acres, yielding a revenue of Rs. 18,56,440.
Panjab.—Of the twenty-one million acres under cultivation in an average year in the Panjab, only five and a half million acres (of which four and a half millions are under food crops) are irrigated by artificial means. One and a half million acres more are situated in the beds of the Panjab rivers, and require little rain to bring their produce to maturity. Of the remaining twelve and a half million acres under food crops (making 184 millions altogether under this description of pro duce), six and a half are pretty safe, being grown under an abundant and a reliable rainfall in the submontane districts, and six millions produce a more precarious crop, being wholly dependent on the less certain rainfall of the tract farther south. It is roughly estimated that on an average for the whole province an acre of irrigated land produces half as much .again as an acre of land wholly dependent on rain. This ratio gives one-third of the total yield of food grains as the produce of irri gated land, and two-thirds as dependent on rainfall or rain-floods. Following out the comparison into more detail, it is calculated that 36 per cent. of the whole supply of food grains is produced by land artificially irrrigated, 43 per cent. by land more or loss protected by floods or abundant rain fall, and only 21 per cent. by land dependent on a more precarious rainfall. The chief means of artificial irrigation are wells, which irrigate three millions of acres ; inundation canals, chiefly from the rivers, of the Panjab proper, irrigate one million ; and perennial canals, of which the Western Jumna and Bari Doab Canals are the chief, protect only three-quarters of a million of acres.