Engineering Wonders of the World
Volume III

244 MAP OF THE GODAVERI DELTA CANALS. Reservoirs. Godaveri Delta Canal System. tributaries, and they in their turn supply thousands of ENGINEERING WONDERS OF THE WORLD. villages with the water which matures the crops. The canals cost somewhat less than a million sterling, and irrigate from 700,000 to 900,000 acres. They owe their inception to the genius of Sir Arthur Cotton. Commenced in 1864, they have brought wealth to the people of the delta. One of the earliest methods of irrigation in India was from surface tanks, which are found in nearly all parts, but are most numerous in Madras, where they number 33,000, and water millions of acres of rice crops. These tanks vary in area from a few acres to nine or ten square miles. More individually important, but really in the same class, are the reservoir systems, which occur chiefly in Bombay. Nearly all the tanks and many of the reservoirs are formed by earthen embank- across local drainages, but in fed from intermittent streams, ments thrown some cases are storing the surplus water of one period for use at a later season. The larger works have been constructed by the British Government. Some have masonry dams varying in height from 100 to 162 feet, built across a gorge to impound the water. The most interesting of these reservoir systems is that ema- nating from the Periyar River, which flows down the west- Periyar River System. ern slope of the Western Ghauts to the Indian Ocean. On this slope there is no irrigable land, whereas on the eastern slope there is plenty. The Periyar system taps the river, stores its water in a reservoir on the western side of the hills, and leads it through a tunnel right across the watershed into the thirsty plains of Madura in Southern Madras. The most interesting feature of this under- taking is the concrete dam, 1,241 feet long and MAP OF THE BARUR TANK SYSTEM IN MADRAS. The tanks are shown as shaded areas.