What you're hearing
Two kinds of running water: the Brook, a small stream right in front of you, and the River, wider and further off. Bring either closer and it takes over; push the other back and it fills in behind.
The Water group also has a waterfall, a fountain, snowmelt, cave drips and a hot spring, and the Brookside starting point puts the brook with wind and light rain. All of them were made with AI and are marked AI in the list.