Lake Hamana

A lake in the southwest of Shizuoka Prefecture. In ancient times it was also called Totsuoumi. The lake shore faces Hamamatsu City from the east to the north, and Kosai City on the west. The area, including Lake Inohana, is 70.4 square kilometers, with a circumference of 103 kilometers and a maximum depth of 12.2 meters. The lake is surrounded by the Osaki Peninsula at the back, the Murakushi Peninsula in the east, and there are many inlets such as Inasa Hosoe, Wadachi Bay, and Uchiura, and the west shore is Matsumiura, making it rich in limbs. The water is deep in the north and shallow in the south, and there are places at the mouth of the lake such as Ose and Ikarise that are less than 1 meter deep. It is a freshwater lake formed when the coastal sandbar was closed due to the uplift of Mikatahara in the east, the development of an eroded valley, and changes in sea level caused by climate change. During the Heian period, the Tokaido road passed over the sandbar, a bridge was built over the Hamana River, and Hashimoto-juku prospered. In 1498 (Meiō 7), a tsunami caused by an earthquake broke the sandbar, opening the lake mouth called Imagireguchi, and seawater flowed in to form a brackish lake. Imagire is located between Arai and Maisaka-juku on the Tokaido road, where a ferry service was operated and Arai Barrier was also built. It is currently connected by the Hamana Ohashi Bridge on the Hamana Bypass. Lake Hamana is a eutrophic and brackish lake, so there are many kinds of fish and shellfish, including 200 species of fish, 70 species of shellfish, and 30 species of crustaceans, as well as a large amount of algae. Lake fishing is also popular, using fishing methods such as bag nets, drift nets, and gill nets. The shallow waters are used for collecting clams, and seaweed and oysters are cultivated, as well as eels and soft-shelled turtles. The area is also rich in tourist attractions, including Kanzanji Onsen, a flower park and zoo, Bentenjima Onsen, Tsubute Island, and a Mikkabi mandarin orange farm, and there are also sightseeing boats that tour Lake Hamana. The Tenryu Hamanako Railway runs along the northern shore, and the Lake Hamana Lakeside Way runs along the Osaki Peninsula. In addition to the Hamana Bridge on the Tomei Expressway, the Hamayu Ohashi Bridge and the Hamanako Ohashi Bridge have also been built.

[Kitagawa Mitsuo]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

静岡県南西部にある湖。古くは遠淡海(とおつおうみ)ともよばれた。湖岸の東側から北側は浜松市に面し、西側は湖西市(こさいし)に面する。面積は猪鼻湖(いのはなこ)を含めて70.4平方キロメートル、周囲103キロメートル、最大深度12.2メートル。湖奥は大崎半島に囲まれた猪鼻湖、東部は村櫛(むらくし)半島により引佐細江、和地支湾、内浦、西岸は松見浦など湾入が多く、肢節に富んでいる。また水深は北部が深く、南部が浅くなり、湖口部には大瀬、碇瀬(いかりせ)など水深1メートル以下の所もある。東部の三方原(みかたはら)の隆起と侵食谷の発達、気候変化に伴う海水面の変化によって海岸の砂州が閉じられてできた淡水湖で、平安時代、砂州の上を東海道が通り、浜名川には架橋され、橋本宿は繁栄を極めた。1498年（明応7）、地震の際の津波によって砂州が決壊して今切口(いまぎれぐち)とよばれる湖口が開け、海水が流入して汽水湖が形成された。今切は東海道の新居と舞坂の宿の間にあたり渡船が行われ、新居の関も設けられた。現在浜名バイパスの浜名大橋で結ばれている。浜名湖は富栄養湖のうえ汽水湖のため魚貝類の種類が多く、魚類200種、貝類70種、甲殻類30種などのほか藻類も多い。袋網、流(ながし)網、刺(さし)網などの漁法による湖面漁業も盛んである。浅瀬のアサリ採貝、ノリ、カキの養殖、ウナギ、スッポンの養殖も行われている。観光資源も豊富で、舘山寺(かんざんじ)温泉、フラワーパークや動物園、弁天島温泉、礫(つぶて)島、三ヶ日ミカンの観光農場などがあり、浜名湖巡りの遊覧船も就航している。北岸を天竜浜名湖鉄道、大崎半島に浜名湖レークサイドウェーが走る。また、東名高速道路の浜名湖橋のほか、はまゆう大橋、浜名湖大橋などが架橋されている。

［北川光雄］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例