+---------------------+-------------+-----------+ | PLACE. | RABI DUTY. |KHARIF DUTY| +---------------------+-------------+-----------+ | | Acres | Acres | | | | | |Upper India |135 to 237[7]| 49 to 120 | |(Punjab and | | | |United Provinces) | | | | | | | |Lower Chenab Canal[8]|133 to 134 | 47 to 88 | |(Punjab) | | | | | | | |Bengal | 56 to 130 | 57 to 113 | | | | | |Bombay | 85 to 118 | 58 to 159 | +---------------------+-------------+-----------+ [7] Occasionally as low as 98 or even 62. [8] The most recent canal. The period of flow in each case would be six months or less. The average rabi duties on the Lower Chenab and Upper Bari Doab Canals, in the Punjab, calculated on the discharges at the distributary heads, for periods of 3 and 5 years respectively, ending March, 1904, were 208 and 263 acres respectively, but in the latter case 11 per cent. of the area received only “first waterings.” For the kharif the figures are 100 and 98 respectively. In Italy the duty is 55 to 70 acres, in Spain from 45 to 205 acres, in the Western States of America generally 60 to 150 acres. In South California the duty is 150 to 300 acres, when, as is usual, surface irrigation is employed, but 300 to 500 acres with subsoil irrigation, the water being delivered in a pipe below ground level (CHAPTER V.) In basin irrigation in Egypt the duty is 20 to 25 acres, but the period of flow is only 40 days. The basins are flooded to about 3 feet in depth. 6. =Sketch of a Project.=--The tract of country to be dealt with in an irrigation project may be limited either by the natural features of the country, by its levels, by the quantity of water available or by financial considerations. If the tract is small or narrow, and particularly if it is not very flat, it may be obvious that there is only one line on which the irrigation channel can conveniently be constructed but in any considerable scheme a contour plan of the whole tract is absolutely necessary. The surveys for such a plan are expensive and take time and it is desirable, as far as possible, to settle beforehand the area over which they are to extend. This may be done to some extent by the examination of any existing levels and of the tract itself. Very high, sandy or swampy ground, whether occurring at the edge of the tract or in the middle of it, may have to be left out. The remainder, as already mentioned, is called the commanded area. When land occupied by houses or roads or which is very much broken, or which for any reason cannot be irrigated, has also been deducted, the balance is the “culturable commanded area.”