The former nature-preserve, where natural forests and Nagaya-ike Pond are effectively arranged, is for enjoying nature, and 'a large lawn area,' 'a valley,' and 'a Japanese garden' (Suikei-en Garden - a water landscape garden) are provided to encourage people visiting there to mingle with each other.
自然保全区域はもともとあった自然林や永谷池を活かし自然を楽しめる区域であり、交流自然区域は人々の交流を目的に「芝生広場」、「谷あい」、「日本庭園（水景園）」等が設置されている。