In relation to the conformation of the islands and the highly fragmented orography, the hydrographic network of Japan lacks extensive basins. The main rivers develop in the Honshū; the Tone, which drains the central section of the island extending its basin on the Kantō plain , and the Kitakami, while the Shinano descends to the Sea of Japan, pay tribute to the Pacific. Unlike these and a few others that develop their basins in longitudinal valleys, such as the Ishitaki and the Teshio, in the Hokkaidō, the rest of the Japanese rivers have more or less direct courses between the watershed and the coast, towards which they maintain a normal direction. We understand how their role, in the geography of Japan, is rather modest. Their courses, youthful in the inland mountainous areas, near the coast extend into the alluvial plains, becoming elements of demographic attraction. They have no importance for the purposes of navigation in a country like Japan all over the coasts; on the other hand they all have more or less immature courses.
On the whole, their regime is rather regular. The power is provided mainly by precipitation which, while having maximums in different periods passing from one region to another, is not lacking in almost any month of the year. In general, however, it rains mainly in summer and autumn in the southwestern section of the archipelago, while in the north-eastern section the abundant winter snowfalls cause spring floods. If the Japanese rivers are of little importance as axes of human attraction, they nevertheless have a fundamental role as water sources for irrigation. Most of the irrigated rice fields (approx. 68%) exploit the river waters, especially in the coastal plains, which represent the main agricultural areas of the country. The springs are rich and numerous throughout Japan, including thermal and thermo-mineral springs, linked to the volcanic nature of the islands. while in the north-east the abundant winter snowfalls cause spring floods. If the Japanese rivers are of little importance as axes of human attraction, they nevertheless have a fundamental role as water sources for irrigation. Most of the irrigated rice fields (approx. 68%) exploit the river waters, especially in the coastal plains, which represent the main agricultural areas of the country. The springs are rich and numerous throughout Japan, including thermal and thermo-mineral springs, linked to the volcanic nature of the islands. while in the north-east the abundant winter snowfalls cause spring floods. If the Japanese rivers are of little importance as axes of human attraction, they nevertheless have a fundamental role as water sources for irrigation. Most of the irrigated rice fields (approx. 68%) exploit the river waters, especially in the coastal plains, which represent the main agricultural areas of the country. The springs are rich and numerous throughout Japan, including thermal and thermo-mineral springs, linked to the volcanic nature of the islands. which represent the main agricultural areas of the country. The springs are rich and numerous throughout Japan, including thermal and thermo-mineral springs, linked to the volcanic nature of the islands. which represent the main agricultural areas of the country. The springs are rich and numerous throughout Japan, including thermal and thermo-mineral springs, linked to the volcanic nature of the islands.
