fellow katsikot i would like to ask for your help...

yesterday i had no choice but to pass through a flooded area. its not that deep but enough to cover my tail pipes (lowered 1.5" 15" mags and 50 series rubber). i had some drinks before i went home and rushed to the flood at around 40kph. my momentum dropped and changed to lower gears. everything was fine after...

the problem started this afternoon when i started my car. some odd loud noise is coming from the engine and i immediately looked for the source. ive isolated the noise from the alternator area. its really noisy and even worst than a cold car warming up. im really suspecting that the noise is coming from the alternator. its like a grinding noise. cant really describe it any better than that. the noise did got a lot more tolerable when i got to my destination but is still a bit noisy.

then tonight, i went home and due to the harsh rain fall, the area was flooded again and this time i switched to 1st gear and rev the at least 3000rpm until i got though the flooded area. as i passed the flooded area, the noise came back worst than this afternoon.

ride: civic 2000 LXi

my question is...
is this an alternator problem?
if so, what kind of damage do you think it sustained?
is it repairable do i need replacement?
how much can this hold me back?

hoping for your replies before i go to a shop so i can have ideas on the probable cause and money ill need.

thanks in advance.