TANK.
Tanken, . GUJ., MAUR. I Eri, TAM' Talao, . . Pmts. I - The tanks or artificial water reservoirs of India, arc the greatest of all the Hindu irrigation works. They are of two kinds,—one excavated and used for drinking water, bathing, and irrigation; the other formed by throwing a bund or dam across the mouth of a valley or across any Sioping ground. The excavated tanks have stone or other steps all round down to the water, generally the whole length of each face ; and in many instances temples have been erec ted around the edge, and little shrines down the steps. Many of the irrigation tanks are of vast extent, with magnificent embankments, in respect to their elevation and solidity. Some of them form lakes many miles in circumference, and water great tracts of country. As insta,nces of this may be mentioned the Red Hill tank near Madras, the Vihar lakes near Bombay ; and in Rajputana, the Raj-Samandar, the tank of Cum bum in the Kurnool district, of Ulsur near Bangalore, of Mir Alam near Hyderabad, and the Hhandara and Lachora reservoirs of Nimar approach the dignity of lakes. Also, a race know-n as the Ghorbuta, at some pre-historic time constructed cyclopean dams in the moun tains of Baluchistan. The tanks of India are named according to their size. The ahar of the N.W. Provinces is a small pond ; johar, a large pond ; other tanks are called pokhar and talao, the last being of masonry ; others are dabra, liwar, talaxi, and garhiya. Sagar is a lake tank of the largest size.
The existing tank irrigation in Southern India is chiefly ancient, and comprises innumerable tanks of all sizes, from what might be termed lakes downwards. These may be divided into three classes :-1. Those formed by the closing of the passage of a considerable river through a narrow gorge, in a range of hills, by MC/IDS of a high dam or bund. 2. Those formed in the plains by em bankments carried aeros,s the drainage of the country, and impounding the water of one or more streams ; these tanks being often of great superficial area, but shallow. 3. Tanks which
might be considered intermediate between the other two, having in general a greater length of darn than the first, and. a greater depth of water than the second. Few examples of the first kind remain entire. The ruined Mudduk Masur tank, one of this class situated on the borders of Dhar war and Mysore, has a length of the main build on the crest, 550 yards ; present height, from 90 to 108 feet ; width at the base, frotu 945 to 1100 feet ; area, of the lake at 90 feet depth, 40 square miles ; contents, about 1400 million cubic yards of water. The area of the drainage basin, which was on the inner dopes of the 1Vestern Ghats, was 500 square miles. Mr. Gorclon was enga,ged on a proposed restoration of this tank, but it was found that the present average rainfall would not suffice to fill much more than one-half of its ancient basin, and it was suggested that the depth should be reduced from 90 to 70 feet. This diminution in the supply was supposed to be attributable partly to the diminished rainfall, and partly to the construction of small tanks on some of the feeders, at a date subsequent to the com pletion of the great tank, which was assigned by tradition to the 14th or 15th century. The main bund was supplemented by two smaller ones, placed on saddles at some distance from it, in tho range of bills ; and it was by the breaching of one of these that the tank was ruined, as the principal embankment remained entire. There were no traces of a waste weir or by-wash of any kind. Of the second and third classes of tanks, some are ancient ones of great dimensions, such as the ruined Poonairy tank, in the Trichinopoly district., of which the embankment was 30 miles in length, and the Vomit= tank, still in action, with a bund 12 miles long.—Elph. p. 163 ; Cameo.