~Canals of the N.W.F. Province.~--Hemmed in as the N.W.F. Province is between the Indus and the Hills, its canals are insignificant as compared with the great irrigation works of the Panjab. The only ones of any importance are in the Peshawar Valley. These draw their supplies from the Kabul, Bara, and Swat rivers, but the works supplied by the first two streams only command small areas. The Lower Swat Canal was begun in 1876, but the tribesmen were hostile and the diggers had to sleep in fortified enclosures. The work was not opened till 1885. A reef in the river has made it possible to dispense with a permanent weir. The country is not an ideal one for irrigation, being much cut up by ravines. But a large area has been brought under command, and the irrigation has more than once exceeded 170,000 acres. In 1911-12 it was 157,650 acres, and the interest earned was 9-3/4 p.c. The Upper Swat Canal, which was opened in April 1914, was a more ambitious project, involving the tunnelling at the Malakand of 11,000 feet of solid rock. The commanded area is nearly 450,000 acres, including 40,000 beyond our administrative frontier. The estimated cost is Rs. 18,240,000 or over L1,200,000 and the annual irrigation expected is 381,562 acres. [Illustration: { Kabul River Canal. Areas commanded by { L. Swat Canal. { U. Swat Canal. Fig. 47. Map of Canals of Peshawar district.] CHAPTER XIV AGRICULTURE AND CROPS ~Classification by Zones.~--In order to give an intelligible account of the huge area embraced by the Panjab, N.W.F. Province, and Kashmir it is necessary to make a division of the area into zones. Classification must be on very broad lines based on differences of altitude, rainfall, and soil, leading to corresponding differences in the cultivation and the crops. For statistical purposes districts must be taken as a whole, though a more accurate classification would divide some of them between two zones. ~Classes of Cultivation.~--The broadest division of cultivation is into irrigated and unirrigated, the former including well (_chahi_), canal (_nahri_), and _abi_. The last term describes a small amount of land watered from tanks or _jhils_ in the plains and a larger area in the hills irrigated by _kuhls_ or small artificial channels. "Unirrigated" embraces cultivation dependent on rain (_barani_) or on flooding or percolation from rivers (_sailab_). (See Table II.)