Abstract
The purpose of this paper is to quantitatively analyze and evaluate the pond’s water storage capacity, quantity of stormwater runoff, rainwater stock, and infiltration capacity. This will help to clarify the function of green infrastructure in Japanese gardens. We selected Sankeien garden in Yokohama as the study site for this research. Sankeien is divided into seven areas: 1. Woodland, 2. Grassland/shrubland (including lawn), 3. Bare ground, 4. Pond, 5. Gravel ground, 6. Paved area, 7. Building ground. The total water volume of the five ponds in the garden is 11,389 (m3). This value corresponds to a rainfall of approximately 60 (mm) per hour. This paper clarified the basic area of Sankeien. The current rainfall-runoff volume is 32,540 (m3/sec). Assuming that the entire Sankeien is paved, the stormwater runoff is 64,680 (m3/sec). The rainwater stock capacity was analyzed by horizontal projected area and surface area. The rain stock capacity by horizontal projected area and surface area were 73.28 (mm) and 74.02 (mm), respectively, which are almost the same value. The present Sankeien can withstand a torrential rainfall of approximately 74 (mm). The infliltration amount exhibits a difference of 171.97 (m3/hr) between the measured value and the theritical value.
https://ror.org/05crbcr45 
