19 FEBRUARY 1927, Page 18

ANTIQUITY OF IRRIGATION

[To the Editor of the SPECTATOR.] Snt,—The Assouan Dam is considered to be one of the seven wonders of the modern world. (Spectator, November lath, 1926.) But there were in Egypt large irrigation works even before the time of Joseph.

For instance, there was the famous Lake Moeris, which was connected with the Nile by means of a large canal. The date of this work is unknown. It is thought that the great embank- ments—the lines of which are still traceable—were built during the 12th Dynasty (2700-2500 a.c.) and Sir Flinders Petrie has found records on its shores of kings belonging to that period. Herodotus, who visited the Lake about 454 WC., states that he was told by. the Egyptians that King Aloeris dug " the lake and built Pyramids in it. The water supplY ' was conveyed " through a channel from the Nile, and for sis. months it flows into the Lake and for six months out again into the Nile." One of the irrigation engineers in the modern Egyptian service estimated that the surface area of Lake Idoeris was 617 square miles, and the contents 1,059,161,000,000 cubic feet. The Assouan Dam was designed to hold 37,612,000,000 cubic feet- of water. So the ancient Lake Moeris must have contained at least 28 times the volume of water conserved by certainly one of the most famous achievements of modern irrigation engineers.

It is not even Mown when this Herculean dam was destroyed, but according to Strabo and Diodorus Siculus it was in exist- ence early in- the Christian Era. Strabo describes it -as " remarkable " and says that " in extent it was as the sea " 4. and the colour of its waters resembles that of the sea."

Again, there are "the waters of Babylon" ; Mesopotamia —which was ruined when irrigation came to end—competes with Egypt for the credit of the earliest historical irrigation works. Referring to irrigation, Herodotus says, " it was not as in Egypt, by the river overflowing the fields " ; but, " it is irrigated by hand and by engines. . . . The territory is intersected by canals, one extending from the Euphrates to the Tigris." The yield of crops was phenomenal. As for the height of the millet, Herodotus will not mention it, as those who have never visited Babylonia would consider it incredible.

In Arabia, irrigation has been practised from time immemorial to the present day. At Morib, in the south western region, are the remains of an abnormally large prehistoric dam across the Wadi Shibwan, constructed by the Ilimaryites. -Some records suggest that Saba the Great began the construc- tion, but all that is definitely known is that it dates back to the misty distance of a remote antiquity. It was destroyed by a tbod about 427 B.C. The name is derived from the Arabic equivalent for " The Great Reservoir of the King." To-day it is in ruins.

In India the ancient Emperors recognized (at a period long before Babylon was a small provincial town) the advantages of large and well-constructed tanks and lakes for drinking and irrigation purposes. From Kautilaya's code (written 321 n.c.), we gather that Chandragupta maintained a special „irrigation department charged with the duty of measuring the lands, and so regulating the sluices that everyone should receive his fair share of life-giving water. The allusion to measurement as a part of the irrigation department indicates that a water rate was levied and the reference to sluices implies a regular system of canals.

There were large irrigation works in existence centuries before the Maurya Dynasty. The Poniary reservoir of 'friehinopoly had an embankment 30 miles in length. But with the exception of Lake Moeris and the Morib darn probably . no conservation work built by any race, ancient or modern, exceeds the colossal magnitude of the stupendous reservoirs in Ceylon. The first recorded dam was built about 504 B.C. The Kalaveva dam, constructed in A.D. 459, consisted of an earthen embankment over 12 miles long. The embankment of the gigantic Kuttucarre works can be traced for more than 15 miles, and the surface area of the reservoir would have been almost equal to that of Lake Geneva. Schemes of such magni- tude, if constructed in modem times, would be world famous.— I am, Sir, &c., J. D. JENKINS. 23 Kahun Road, Poona, India.