bln m3. The main tributaries of Hii are Ai, Ohmaki, Kuno, Mitoya and Akagawa. In addition, rivers Iinashi and Hakuta discharge into lake Nakaumi. In the upper part of the catchment over 80% of the land is covered by forests and around 10% by rice paddies. History and mythology During the Last Glacial Maximum, the was fully connected to Honshu. The Old Shinji river flowed in the place of modern lake Shinji and Izumo Plain. About 9000 BC the sea level began to rise and seawater intruded into the low-lying areas in the east and the west ends, between the hilly peninsula and Chūgoku Mountains. During the temperature peak of the warm Atlantic period (early Jomon) the sea probably separated the peninsula almost entirely from the mainland. At that point the Hii river flowed into the Old Shinji Bay, located at the place of modern lake Shinji and Izumo Plain. Later the sea level receded again. In addition, sediments from Hii and other rivers accumulated in the bay, cutting it off the sea. The final step in this change may have happened as a result of an eruption of about 1600 BC and the obstruction of the bay by pyroclastic flow that connected it again to Honshu. Afterwards rivers Hii and Kando discharged into the Kandono-mizuumi lagune and deposited their sediment there. According to some researchers, this change may have been reflected in the Kunibiki-shinwa ("Land-pulling myth"). It tells the story of the expansion of Izumo land by pulling to it pieces of "land in excess" from neighbouring areas. According to the Izumo-fudoki annals, the local deity Yatsukamizu-omitsuno(-no-mikoto) said: "The country Izumo, of the clouds rising, is a land like a pile of narrow cloth. First the land was made small. Therefore, it ought to be sewn larger". Using a hoe he pulled pieces of land from Shiragi (eastern Silla), Saki Country and other areas and connected them to Izumo to form the Shimane peninsula. The land pulled from Shiragi became Kidzuki Cape, beside which Izumo Taisha shrine is located. Its original name was Kidzuki-oyashiro and it was dedicated to Yatsukamizu-omitsuno. In another local myth the fight of Susanoo against Yamata no Orochi serpent may represent the flood control efforts of people living along Hii. Till the mid-18th century, after reaching Izumo plain, the Hii turned west and discharged into Taisha Bay of the Sea of Japan. The sediments accumulated