| Madiun River | |
| Name Other: | Kali Bengawan Madioen, Kali Madioen |
| Map Size: | 285 |
| Pushpin Map: | Indonesia Java#Indonesia |
| Pushpin Map Size: | 285 |
| Pushpin Map Caption: | Location of the mouth |
| Subdivision Type1: | Country |
| Subdivision Name1: | Indonesia |
| Subdivision Type2: | State |
| Subdivision Name2: | Jawa Timur |
| Subdivision Type5: | City |
| Subdivision Name5: | Madiun |
| Source Confluence: | Some tributaries |
| Source Confluence Location: | Ponorogo |
| Mouth: | Solo River |
| Mouth Location: | Ngawi (town) |
| Mouth Coordinates: | -7.388°N 111.4577°W |
The Madiun River (Indonesian: Bengawan Madiun or Kali Madiun) is a river in East Java, Indonesia, about 500 km to the east of the capital Jakarta.[1] It is the largest tributary of the Solo River.[2] Its name indicates that it passes through the major city of Madiun, East Java, Indonesia.[3] This river starts as several smaller tributaries converging near the city of Ponorogo, in particular the Kali Slahung, Kali Keyang, and Kali Sungkur.[4] It eventually converges with the Solo River near the city of Ngawi.[5]
In 1825, the Dutch East Indies soldiers built a fortress near the convergence of the Madiun and Solo rivers, to fight a local rebellion led by Diponegoro. The fortress was named Fort Van Den Bosch;[2] known locally as Benteng Pendem Ngawi.[6]
The river flows entirely within the Province of East Java, passing through Ponorogo Regency, Madiun Regency, City of Madiun, Magetan Regency, and Ngawi Regency, with a savanna climate.[7] The annual average temperature in the area is 26 °C. The warmest month is October when the average temperature is around 30 °C, and the coldest is January, at 24 °C.[8] The wettest month is March, with an average of 546 mm of rainfall, and the driest is September, with 21 mm of rainfall.[9]
For ages, the Madiun River has notoriously caused flooding during the rainy season.[10] Every year the seasonal deluge submerges many fields and houses along the river banks, including some districts in Ponorogo Regency in the upper reaches[4] and in the Ngawi Regency in the lower reaches.[11] [12] [13] The high debit of water overflows to the Solo River, adding to the regular flooding in Bojonegoro Regency.[14] During the dry season, the river becomes a tourist place for fishing or a place to mine sands for local people.[15]