actually is as what you say lor, improper control of the river.
If you recall at one time they suggested Pahang as a replacement
site for new water source but it was remote and undeveloped hinting
that we would be the main sponsor for the site in Pahang which we
of course didn't want as we already spent abt over 1 billion to
build up the johore site.
So actually they have a lot of water resources if they implement
the correct infrastructure.