{{Infobox river | name = Hija River | native_name = {{native name|ja|比謝川}} | image = File:Hijagawa Okinawa Japan.jpg | image_caption = The Hija River in Kadena | subdivision_name1 = Japan | country_type = Country | subdivision_type2 = Prefecture | subdivision_name2 = Okinawa Prefecture | length = {{convert|15.4|km|mi|abbr=on}} | basin_size = {{convert|50.4|km2|sqmi|abbr=on}} | tributaries_right = Kahunja River, Yonabaru River, Nagata River | name_native = | mouth = East China Sea | mouth_coordinates = {{coord|26.3628|127.7409|format=dms|type:river_region:JP|display=inline,title}} | source1_location = Okinawa City, Okinawa }}
The '''Hija River''' {{Nihongo|2=比謝川|3=|lead=yes|4=''Hijagawa''}} is the largest river on the Japanese island of Okinawa. It runs through Okinawa City and meets the East China Sea on the western side of the island between the municipalities of Kadena and Yomitan. It supplies much of the island's drinking water.
==Course== The Hija River originates from a group of hills in the southern portion of Okinawa City in the central portion of the island of Okinawa. It flows north through a densely urbanized portion of the city, receiving the Kahunja River from the east as it passes through the neighborhood of Misato. Soon after this, it turns west, and receives additional tributaries, including the Yonabaru River to the north. After passing under a stretch of National Route 58, it joins with the Nagata River, and then drains into the East China Sea on the western side of the island, at the border between Kadena and Yomitan.{{sfn|Okinawa Prefecture|2019|p=1}}
==Description== The Hija River has a length of {{convert|15.4|km|mi}} and a drainage basin measuring {{convert|50.9|km2|sqmi}} in area. It is the largest river on the island of Okinawa. The area exhibits a humid subtropical climate, with annual rainfall averaging around {{convert|2000|mm|ft|abbr=on}}, and an average annual temperature of {{convert|23|C|F}}. Along with its largest tributary, the Yonabaru, it supplies much of Okinawa's drinking water.{{sfn|Okinawa Prefecture|2019|p=1}}
The upper portion of the river basin is composed largely of mudstone of the Shimajiri Group. Regions of conglomerate rocks are found within the northern areas of the basin, while much of the southern region consists of limestone.{{sfn|Okinawa Prefecture|2019|p=1}}
The central reaches of the river run through a forested environmentally-protected area, which includes dense groves of Ryukyu pines.{{sfn|Okinawa Prefecture|2019|p=1}} Much of the river's watershed lies within American military bases. During the Ryukyu Kingdom, a large stone bridge was built at the river's mouth near Yara Castle. This was destroyed during the Battle of Okinawa, following which a new bridge at the site was built by American forces.<ref>{{Cite web |date=11 January 2024 |title= |script-title=ja:比謝川 |trans-title=Hija River |url=https://www.pref.okinawa.lg.jp/machizukuri/kaigankasen/1013119/1013133/1023852/1013136.html |access-date=22 March 2026 |website=Okinawa Prefecture}}</ref>
The region around the river's estuary mainly consists of sand and gravel, with a small amount of coral, especially of the subfamily Faviinae and the genus ''Acropora''.{{sfn|West|Van Woesik|2001|pp=868–870}}
==References== {{reflist}}
===Bibliography=== {{refbegin}} *{{cite journal|first1=K.|last1=West|first2=R.|last2=Van Woesik|date=2001|journal=Marine Pollution Bulletin|volume=42|issue=10|pages=864–872|title=Spatial and Temporal Variance of River Discharge on Okinawa (Japan): Inferring the Temporal Impact on Adjacent Coral Reefs}} *{{cite report|publisher=Okinawa Prefecture|trans-title=Hija River Basin River Improvement Plan|script-title=ja:比謝川水系河川整備計画|language=ja|date=2019|url=https://www.pref.okinawa.lg.jp/_res/projects/default_project/_page_/001/013/131/hijyagawaseibikeikaku.pdf|ref={{harvid|Okinawa Prefecture|2019}}}} {{refend}}
Category:Rivers of Okinawa Prefecture