494, REPORT—1905. 
Italian Irrigation. 
For the study of high-class irrigation there is probably no school so good as is 
to be found in the plains of Piedmont and Lombardy. Every variety of condition 
is to be found here. The engineering works are of a very hich class, and from 
long generations of experience the farmer knows how best to use his water. 
The great river Po has its rise in the foothills to the west of Piedmont. It is 
not fed from glaciers, but by rain and snow. It carries with it a considerable 
fertilismg matter. Its temperature is higher than that of glacial water—a point to 
which much importance is attached for the very valuable meadow irrigation of 
winter, From the left bank of the Po, a few miles below Turin, the great Cavour 
Canal takes its rise, cutting right across the whole drainage of thecountry. It has 
a full-supply discharge of 2,800 cubic feet per second ; but it is only from October 
to May that it carries anything like this volume. In summer the discharge does 
not exceed 2,200 cubic feet per second, which would greatly cripple the value of 
the work were it not that the glaciers of the Alps are melting then, and the great 
torrents of the Dora Baltea and Sesia can be counted on for a volume exceeding 
6,000 cubic feet per second. 
Lombardy is in no respects worse off than Piedmont for the means of irriga- 
tion; and its canals have the advantage of being drawn from the lakes 
Maggiore and Como, exercising a moderating influence on the Ticino and 
Adda rivers, which is sadly wanted on the Dora Baltea. The Naviglio: 
Grande of Lombardy is drawn from the left bank of the Ticino, and is used largely 
for navigation, as well as irrigation. It discharges between 3,000 and 4,000 cubic 
feet per second, and nowhere is irrigation probably carried on with less expense. 
From between Lake Maggiore and the head of the Naviglio Grande a great 
new canal, the Villoresi, has been constructed during the last few years with head 
sluices capable of admitting 6,700 cubic feet per second, of which, however, 
4,200 cubic feet have to be passed on to the Naviglio Grande. Like the Cavour 
Canal, the Villoresi crosses all the drainage coming down from the foothills to 
the north. This must have entailed the construction of very costly works. 
Irrigation in Northern India. 
It is in India that irrigation on the largest scale is to be found. The great 
plains of Northern India are peculiarly well adapted for irrigation, which is a 
matter of life and death to a teeming population all too well accustomed to a 
failure of the rain-supply. 
The Ganges, the Jumna, and the great rivers of the Punjab have all beer 
largely utilised for feeding irrigation canals. The greatest of these, derived trom 
the river Chenab, and discharging from 10,500 to 3,000 cubic feet per second, was 
begun in 1889, with the view of carrying water into a tract entirely desert and un- 
jopulated. It was opened on a small scale in 1892, was then enlarged, and ten 
years after it irrigated in one year 1,829,000 acres, supporting a population of 
800,000 inhabitants, colonists from more congested parts of India, 
The Ganges Canal, opened in 1854, at a time when there was not a mile of 
railway, and hardly a steam engine within a thousand miles, has a length of about 
9,900 miles, including distributing channels. It was supplemented in 1878 by a 
lower canal, drawn from the same river 130 miles further down, and these two 
canals now irrigate between them 1,700,000 acres annually. On all these canals are 
engineering works of a very high class. The original Ganges Canal, with a width 
of bed of 200 feet, a depth of 10 feet, and a maximum discharge of 10,000 cubic 
feet per second, had to cross four great torrents before it could attain to tbe water- 
shed of the country, after which it could begin to irrigate. Two of these torrents 
are passed over the canal by broad super-passages. Over one of them the canal is 
carried in a majestic aqueduct of fifteen arches, each of 50 feet span ; and the fourth 
torrent, the most difficult of all to deal with, crosses the canal at the same level, a 
row of forty-seven floodgates, each 10 feet wide, allowing the torrent to pass 
through and out of the canal. 
