The Hiruzen Plateau is the source of the Asahi River, which flows from Hiruzen south across the Okayama Plain, and empties into Kojima Bay on the Inland Sea in the eastern part of Okayama City. The Shiogama-reisen Cold Spring is designated as the source of the river, and is a protected natural habitat of the Japanese giant salamander. Yubara Dam, on the upper reaches of the Asahi, is approximately from Hiruzen and was completed in 1952. The dam forms an artificial lake, Lake Yubara (), directly to the southeast of the Hiruzen Plateau. The Hiruzen Plateau has also developed recreational facilities for camping, skiing, and fishing.