Beyond the Plunge Pool, a stone path leads across a two-level Koi Pond. The smaller pond, to the right in the photo, has been designed to act as a spring, with water flowing in between the large flat stepping stones, and dropping about 6" into the larger Koi Pond on the left. This very short waterfall helps to aerate the water, and create a tranquil, rather than robust sound of water. Photo by Glen Grayson, AIA