Add something to cushion the water's fall. My first suggestion is to put something soft in the pool to essentially break the water’s fall. This will help to disperse the noise and reduce any irritation from the splashing.
2. Use air bubbles to disrupt the water surface tension. Bubbles are unpredictable, breaking up the sound of droplets falling into the pool, which can be helpful for beginners or those who want a less formal atmosphere in their pool setting.
3. Run the water down a smooth surface. When waterfalling water moves quickly it creates turbulence, which amplifies noise levels. Direct it along the bottom of the pool or turn off neighbouring pumps while the falls are on, helping to drown out the sound of cascading water.
4. Build some sound baffles. By blocking off certain sections of your pool with simple boxes or other structures you can help to reduce noise levels significantly - particularly if you have waterfalling that is occurring