Too many water departments, far too many chiefs, not enough indians with not enough overall knowledge and no overall communications with each other, let alone provinces up and down stream.
As an example. The RID decides that the dam in the North is getting a bit full, opens the sluice gates a bit until the water level is about right, brings the sluices back and his problem is solved.
Absolutely correct, HIS problem IS solved.
This goes on all the way down stream to Bangkok. who have no control over how much comes down to them.