SubDrag will be supporting it in the N64SoundTool. If you're impatient the settings are:
[Wild Waters]:type=N64WavePtrTableV2
0031AFB0,0031CB70
0050E2F0,0050FEB0
The second stage doesn't work. The WW data appears to end at 0x800000, at which point the remnant of some other game's display list starts.