  The neutrinos and antineutrinos of all the three flavors released from a
galactic supernova will be detected in the water Cerenkov detectors. We show
that even though the neutral current interaction is flavor blind, and hence
neutrino flavor mixing cannot alter the total neutral current signal in the
detector, it can have a non-trivial impact on the delay of massive neutrinos
and alters the neutral current event rate as a function of time. We have
suggested various variables of the neutral and charged current events that can
be used to study this effect. In particular the ratio of charged to neutral
current events can be used at early times while the ratio of the energy moments
for the charged to the neutral current events can form useful diagnostic tools
even at late times to study neutrino mass and mixing.
