Tone River

Tone-gawa (English name Tone-gawa) is the largest river in Japan. It originates from Dashuishan in Tone-gun, Gunma County. It runs through mountains and mountains in the east to the south of the main stream, traverses the Kansai Plain, and joins more than 280 tributaries. The river is 322 kilometers long, with a drainage area of 16,840 square kilometers; the annual runoff is 12.4 billion m3, and the average annual flow is 400 m3/s. The upstream section of the main stream from the source to Badou Island, the middle section from Badou Island to Toride, and the downstream section from Toride to the estuary. The composition of the Tonegawa water system is distinctive. Due to the small size of Japan, the north and south are long and narrow, and the spine and mountains run through it. The distance between the mountain and the coast is short, so that after the river flows out of its source mountain, it is injected into the sea only after a short distance, forming the characteristics of short rivers. Therefore, although there are more than 280 large and small tributaries of the Tone River system, most of them are only It is a mountain stream and a small river with a length of less than 20km and a drainage area of less than 200km2. The main tributaries are Katshinagawa, Azuma River, Ugawa, Nara River, Edo River, Kinu River, Xiaobei River and Hitachi Tone River.