Here are some sounds I grabbed from White Water during play.
The sounds are all in .WAV format. Most are 15s. or less (none are over 30s.).

1. GAME START: Game Start / Skill shot!
2. MULTI MILLION: "Multi millions!" / Raft advance
3. EXTRA BALL: Extra ball lit / Extra ball awarded!
4. HELP!: Man overboard mode / man saved!
5. BOULDER BASH: "It's a boulder bash!"
6. SECRET: "Hey, you found the secret passage"
7. MINE: Shot into mine / end of ball bonus
8. MULTIBALL: Multiball started / Double jackpot!
9. WET WILLIES: Wet Willies started.
10. HIGH SCORE: Initials entered / Match + music.