314 



A short Account of the 



[Oct. 



which broke its north bank a little below Trivial' and went bodily into 

 the Colleroon, covering many thousand cawnies of valuable land with 

 sand, and leaving all its eastern cultivation entirely without water. The 

 loss, both to the land owners and to Government, caused by such acci- 

 dents, was of course very great, and to prevent them, the embankments 

 were everywhere strengthened and raised. Breaches have since there- 

 fore been less frequent, and the bed of the Cauvery continued to rise 

 till for several years it had been a constant cause of alarm. The 

 under-sluices were first suggested by Major Sim as a safe remedy for 

 this evil, and the construction of them was commenced by Captain Fa- 

 bet in 1830 ; they appear to have answered their purpose, for nothing 

 is now heard on the subject of the sands. These works are of masonry 

 with several vents lined with granite, and placed in as low a level as 

 possible, so as to be much below the general level of the sands in the 

 river ; a channel leads from them to the Colleroon, and as the Cauvery 

 flows on a level of from one to twelve feet above that of the Colleroon, 

 the water passes through the sluices with great velocity, and carries oif 

 the sand in very large quantities. They are only opened when there is 

 more water in the river than is required for the cultivation. The first of 

 these works is situated about two miles below the head of Seringham ; 

 it has iweuty sluices and is calculated to discharge from 500,000 to 

 one million cubic yards of water per hour. The second set of ten vents is 

 in the body of the grand annicut ; the third about four miles west of Tri- 

 vial*, and the fourth about ten miles east of that town. Of these, however, 

 only two sets have yet been used to any considerable extent, the others 

 having been more recently completed. Another set of works have alsp 

 been constructed of late years to assist in regulating the distribution of 

 the water through the district. The heads of the different branch 

 rivers undergo continual changes, unless constantly watched ; but even 

 a single fresh often much widens or deepens the head of a branch, or 

 throws up sand across it, so as materially to alter the proportion of 

 w r ater which it receives ; in this manner, notwithstanding great atten- 

 tion, a river frequently gets much less or much more than the propor- 

 tion of water due to its extent of cultivation ; as a partial remedy for 

 this, and one which could be applied on the instant, three channels 

 were cut, connecting each two of the principal rivers, and furnished 

 with sluices at their heads, by means of which a portion of water 

 could be let off from the one river to the other when it was necessary. 

 Two new annicuts have also been just constructed across the Colle- 

 roon, one at its head, that is, at the head of Seringham ; this work is 

 about eight hundred yards long, and is intended to turn a larger body 

 of water into Tanj ore during the low freshes. Hitherto the division 

 of the waters of the Agunda Cauvery has only been regulated so 

 far as could be accomplished by attending to the state of the head 



