1836.] 



Irrigation of the Delta of Tanjore. 



313 



built over the Vennaur near Tanjore, at the expence of His Highness 

 the Rajah, who deserves great credit for so useful an application 

 of money. After passing Conibaconum the Cauvery throws off the 

 Verasholen from its south bank. At Myaverum its breadth has 

 diminished. Here a private native gentleman is now constructing 

 a bridge. Before it reaches the sea it is only three or four yards 

 broad, and it is only in very good freshes that any water ever enters 

 the sea by it. No rivers lead off from the north side of the Cauvery j 

 but innumerable irrigating channels, of all dimensions, flow from it, as 

 well as from every other river in the district ; almost every one being 

 provided with a sluice at the head, which is shut when there is too 

 much water in the river,. 



All the various rivers are also embanked on both sides, with the ex- 

 ception only of one or two places, where several rivers approaching 

 very near to each other, no banks have been constructed, and in very 

 high freshes the water there spreads all over the intermediate lands. 

 The total length of embankment in the Delta is not easily estimated, 

 but it can scarcely be less than two thousand miles varying from one to 

 six yards in height There are live large works on the Cauvery, which 

 have not yet been mentioned ; one of these is a Calingulah, or work for 

 the discharge of surplus water ; it is situated on the island of Seringham 

 about four miles from its head, and forms an opening in the north 

 bank of the Cauvery ; it is one hundred and fifty yards in length, and 

 is intended to allow a large body of water to flow back from the 

 Cauvery into the Colleroon in very high freshes, where the south 

 embankment of the Cauvery near Trichinopoly, and all parts of 

 the embankments in Tanjore are always much endangered, and have 

 been frequently breached. The other four works alluded to above, 

 are what are called under-sluices. The Cauvery and many of its 

 principal branches having no clear outlet to the sea, the sands brought 

 down from the westward are of necessity deposited in the beds of 

 the rivers and of the irrigating channels ; from the latter it was 

 cleared out annually by manual labour, and in the former much la- 

 bour was constantly expended in cutting channels through particular 

 accumulations, but of course no permanent effect could be produced on 

 a river of this size by such means ; the bed of the rivers thus gradually 

 rose, to the great danger of the neighbouring lands and villages ; for 

 where a breach took place all the cultivation in its neighbourhood was 

 buried several feet deep in sand. Formerly it appears that after this 

 evil had arrived at a certain height, it corrected itself, in some measure, 

 by the river making a complete breach and going bodily into a neigh- 

 bouring branch, which, from having a clear outlet to the sea, flowed on 

 a lower level, and into which very large quantities of sand were thus 

 discharged. This was the case some years ago with the Cauvery, 



