184 B. R. BranCll — Pliysiograpliical Xotes on Tanjore, Sfc. [No. 4, 



This diversion may have occurred either above or below what is now 

 the island of Srirangam, lying like a sand-bank in mid-river. If it occur- 

 red above, it seems likely that the new channel or northern branch (the 

 Kolladam*), soon became the deeper bed of the two, and then either ap- 

 proached and threatened, or actually breached the north bank of the 

 southern or old Kaveri branch below the island, and the ' grand anaikat' 

 (dam or weir), which is strictly a river- wall or ' levee', must have been 

 built to prevent or repair a breach. 



If, on the other hand, the breach or bifurcation occurred below Sriran- 

 gam, the ' grand anaikat' was probably made to repair it and keep the 

 stream back in its own channel : but if so, the attempt was ineffectual, for 

 the river must have then formed a new bed for itself, some miles higher up 

 the channel, at a point nearly opposite a place marked on the map (Indian 

 Atlas, Sheet 79) as ' Palaya Cauvery' (Old Cauvery). 



In either case, the northern channel, which flows along the left or 

 northern border of the delta, and immediately under the gravel up-lands of 

 north-east Trichinopoly, became the deeper and wider one, carrying off the 

 high floods, whilst the south or old Kaveri branch, kept at a higher level 

 with impeded stream and checked by numerous irrigation works, gradually 

 silted up and threatened to leave Tanjore un watered, for the bed of the 

 Kolladam was too deep to admit of irrigation channels being profitably led 

 from it. The difference of level of the two beds at the grand anaikat is 

 variously stated to have been from 10 feet to 20 feet early in this (19th) 

 century and to be rapidly increasing. 



In this state the British Government took charge of the district 

 and, after trying many other expedients to save and restore the Kaveri 

 irrigation, in 1836 constructed first the upper anaikat, a weir or dam across 

 the head of the northern branch or Kolladam, in order to raise the stream, 

 so as to flow into the Kaveri Proper or southern branch. This proved more 

 than sufficient in times of high floods, and there was danger of overwhelming 

 Tanjore by a sudden inundation from pouring in an excessive supply. To 

 remedy this, sluices were formed in the ' grand anaikat' to provide an escape 

 for the sand and surplus water that was not wanted, and finally a head- 

 sluice or regulating dam was made across the Kaveri channel where it 

 enters the delta, below the ' grand anaikat,' thus giving the means of regu- 

 lating the supply as desired. 



The Kaveri proper continues its course through the delta with a 



* ? Kolai-(y)-idam = * Slaughter place', from a legend tliat men were cast into a 

 chasm througli -which the Kaveri had disappeared, in order to fill it up ; a story that 

 looks as if a human sacrifice had been performed at the repair or filling up of a great 

 "breach. Kollayi = a breach in a bank (Gundert). Another suggests Kilai-y-i dam = 

 ' "bifurcation-place', from kilai, a branch, bifiucation &c. 



