Why do the two sides differ on water allocation?

This topic came about as I was going through this call to stop paying for government services in Telangana by the convenor of the JAC. (All this will do is cripple the local economy with potential to lay off local jobs in govt and semi-govt corporations. There will also be confusion amongst the populace, iam sure some private sector providers of govt services will also suffer as they do not have the deep financial pockets to provide services.) 

The hindu "Kodandaram said that much injustice was done to Mahabubnagar district in allocation and utilisation of Krishna River. Though Bachawat tribunal allocated 15.90 TMC ft of water to Rajolibanda Diversion Scheme (RDS) that was constructed across Thungabhadra River to benefit Mahabubnagar district but only 5 tmcft of water was being flown into the ayacut of the district, he deplored."

Is this true? Why did this happen? Another source says:  

"Professor Jayashankar’s statement is an outrageous distortion. He must know that Bachawat, after extensive study, awarded water to each state based on the “protection of existing uses” principle. As a result, existing projects on Krishna and Godavari are protected. Based on this principle, despite having a smaller catchment area, Bachawat allocated a larger share of Krishna River water to the Andhra Pradesh State."
http://www.myteluguroots.com/chapter_19_12.html

(Professor Jayashankar does state Bachawat allocations were per state and it was prerogative of state to suballocate these waters http://www.telangana.org/Papers/Article10.pdf)

It is clear that the TRS says when determining water allocation catchment area as  its principal critereon. (So I guess Bachawat never mentioned allocation to specific projects? So where is JAC Convenor Kondaram getting his facts linking to Bachawat to said injustice?)

"Detailing on the injustice meted out to the people of Telangana region, the TRS chief said, "If the catchment area is taken as the principal critereon for allocation of water among different regions in the state, Telangana region should get 68.5 pc of the 811 tmc".

So the conflict seems to be between two principles. "Water allocation by Catchment area" vs "Existing uses principles".

Are either of these principles correct? With India hurtling towards a market economy, these old fashioned ideas of water allocation by a powerful tribunal needs to be discarded.

The real debate, should be about truth and the truth in a market economy is based on profit, margins, capital costs for irrigation, operation costs (such as electricty pmuping costs via lift irrigation). 

However, the debate itslef is so superficial to be dumb (or populist). In any other part of the world where wealth has been generated by capitalist principles, we wouldn't even be discussing these two outdated socialist principles for allocation of resources.

This is a reminder that it is not just lack of infrastructure that is holding the Indian Economy back. A lack of proper debate is also holding us back. EU and US struggle to implement market principles to the rural community... however at least there is robust debate on showing the wastefulness of rural subsidies.