I speak of the Kaveri.
As you know, the river is dammed at Srirangapatnam, and therefore during the monsoons the water outflow from the dam has to be increased so that max storage level is maintained, but at the same time the dam doesn't go bust.
The rain itself mucks up the colour of the water due to the silt that pours in from the banks, but that clears in a couple of days. What really colours the water is the combination of rain and heavy water flow in and out of the dam. And as you know that can be a real turn off for the mahseer.
I think it's safe to say, that you need to see your toes in 3 to 4 ft of water to have much of a chance of a mahseer take. Though at times a bright spoon or a chilwa can produce the odd good fish in slightly murky water.
High water levels usually mean colder water, and our southern bretheren aren't too happy about eating in the cold, so fishing is invaribly slower than when the water is of medium level.
Most of our southern mahseer tend to move up river (when rivers permit) just before the monsoons. As the water levels begin to drop, which is usually in december. they make their way down to their summer haunts in the rapids and deep pools.
As summer sets in and the water levels drop, and warms up a bit, the fish begin to feed more freely. But as summer progresses, water levels begin to drop rapidly and the shallow water tempreature begins to rise.
The larger fish move into deeper pools and lay low most of the time.
Due to water treaties between southern states, there are unexpected releases of water from the dams, which can make your entire calculations go haywire.
Then comes that magical moment, when they start to move up river again.
Anyone who has seen this mass movement of fish, will vouch that it indeed is a sight to behold.
The water is usually clear and shallow enough to see the fish gradually move upriver. Stopping occasionaly at the top of fast water stretches to take a breather.
I have been told by reliable sources that in times gone by, the bed of the river would be covered with fish in stretches, as they made their way up river, but they usually aren't too interested in a meal on their way up.
Thats it mate. Make what you will of it.