|Primary outflows||Pacific Ocean|
|Surface area||63.2 km2 (24.4 sq mi)|
|Average depth||11 m (36 ft)|
|Max. depth||25 m (82 ft)|
|Water volume||0.714 km3 (579,000 acre·ft)|
|Residence time||0.8 years|
|Shore length1||67.4 km (41.9 mi)|
|Surface elevation||0 m (0 ft)|
|Frozen||December to March|
|1 Shore length is not a well-defined measure.|
Lake Ogawara (小川原湖 Ogawarako) is Japan's eleventh largest lake (by area) and the largest in Aomori Prefecture. It spans the boundaries of the city of Misawa and the town of Tōhoku and the village of Rokkasho in Kamikita District.
The lake has an area of 63.2 km² and holds 0.714 km³ of water. Its circumference is 67.4 kilometers. At its deepest point, the water is 25 meters deep, with an average depth of 11 meters. The surface is at sea level. The lake is shallow (under 2 meters) from the shoreline to a distance of approximately 200 meters, whereupon the depth drops off precipitously. The edge of Lake Ogawara is very near the coast of the Pacific Ocean, and the sand bar guarding its mouth has been breached numerous times by storms or typhoons, thus accounting for the brackish water of the lake. There are four inflowing rivers, all coming from Hakkoda Mountain Range. The only outflow is the Takase River, which drains the lake to the Pacific Ocean.
Lake Ogawara was originally a marine bay, which became a lake approximately 3,000 years ago by the formation of a sand bar at its mouth. The shoreline around Lake Ogawara has been settled since prehistoric times, and numerous Jomon period remains and shell middens have been discovered.
The lake was used by the Imperial Japanese Navy Air Service units at Misawa Airfield to practice for the attack on Pearl Harbor during World War II for its similarity in depth to Pearl Harbor in Hawaii.
The Japanese government initiated a project beginning in the 1970s to convert the lake from brackish to fresh water to serve as a source of drinking, industrial and irrigation water despite the adverse environmental impact.
In the year 2002, the Ministry of the Environment classified Lake Ogawara to be one of the 500 Important Wetlands in Japan particularly for its biodiversity of aquatic flora, insects, freshwater shellfish and as a habitat for migratory wildfowl.
This article incorporates material from the article 浜名湖 (Ogawarako) in the Japanese Wikipedia, retrieved on November 11, 2009.
- Geospatial Information Authority of Japan (2015-03-06). "平成26年全国都道府県市区町村別面積調 湖沼面積（20傑）" (PDF). Retrieved 2015-03-08.(in Japanese)
- "北海道・東北 - チャグチャグ馬コの鈴の音". Ministry of the Environment. Archived from the original on 8 June 2012. Retrieved 18 April 2011.
- "500 Important Wetlands in Japan". No. 64 Ogawara-ko Wetlands (including Obuchi-numa, Takahoko-numa, Ichiyanagi-numa, Tamogi-numa, Takase-gawa and Ogawara-ko). The Ministry of the Environment, Japan. 2002. Retrieved 4 March 2017.
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