The figures on which the discharges in the Triple Project are based form a useful and interesting object lesson. In order to obtain sufficient water in the winter, it is necessary to reduce the rabi supply to the existing Lower Jhelum Canal. The figure above given for the Jhelum indicates the supply available after the reduction. More water will be supplied to the Lower Jhelum Canal for the kharif, the canal being enlarged for this purpose, and its total irrigation will be unaffected. The proportion of the culturable commanded area to be irrigated in the new tracts is 75 per cent., but from this the area irrigated by wells in the Upper Jhelum and Upper Chenab tracts is deducted. On the Lower Bari Doab Canal there is little well Irrigation, but there are some low-lying tracts near the rivers, and of these only 50 per cent. will be irrigated. The kharif and rabi areas are in all cases to be equal.
The areas to be irrigated in each crop are as below—
| Lower Jhelum Canal | 383,091 | acres |
| Upper Jhelum Canal | 172,480 | „ |
| Upper Chenab Canal | 324,184 | „ |
| Lower Bari Doab Canal | 441,264 | „ |
| Total | 1,321,019 | „ |
The total, excluding the existing Lower Jhelum Canal, is 937,928 acres. With an equal area in the other crop, the new annual irrigation amounts to 1,875,856 acres.
The kharif duty is taken as 100 acres at the distributary heads, this being about the figure actually obtained on the Lower Chenab and Upper Bari Doab Canals, and the required kharif discharges at the distributary heads are:
| Lower Jhelum | 3,821 | c. feet per | second | |||
| Upper | „ | 1,725 | „ | „ | ||
| „ | Chenab | 3,242 | „ | „ | ||
| Lower Bari Doab | 4,413 | „ | „ | |||
| Total, excluding Lower Jhelum | - | 9,380 | „ | „ | ||
The losses of water in canal and branches have been found to be, on the Upper Bari Doab Canal 10 c. feet per second, and on the Lower Chenab Canal 8 c. feet per second, per million square feet of wetted area respectively. The conditions of the latter canal most resemble those on the new canals under consideration. The losses calculated on the wetted areas of the channels, as designed, at 8 c. feet per second per million square feet, are as follows, in c. feet per second:
| Lower Jhelum Canal | 624 | - | 1,288 | |
| Upper Jhelum Canal | 664 | |||
| Upper Chenab Canal | 1,161 | - | 2,126 | |
| Lower Bari Doab Canal | 965 | |||
| Total | 3,414 | |||
But in dry years the canals will be worked in rotation during the rabi, the Upper Chenab and Lower Bari Doab Canals being worked together, and the Upper Jhelum and Lower Jhelum together.
When the Lower Jhelum Canal is closed, in course of rotation, the Upper Jhelum Canal will still be flowing, and the loss in it, 664 c. feet per second, has to be added to the figure (2,126) given above, thus bringing up the loss to 2,790 c. feet per second.