Lake Kasumigaura 3.17

Lake Kasumigaura is the second-largest lake in Japan, located 60 km to the north-east of Tōkyō.In a narrower sense and officially, Lake Kasumigaura refers to a waterbody with an area of 167.63 km2. In a wider sense, Lake Kasumigaura can also refer to a group of contiguous lakes, which includes Lake Kasumigaura proper, hereby referred to as Nishiura (西浦), and two smaller lakes, Kitaura (北浦; 35.16 km2) and Sotonasakaura (外浪逆浦; 5.85 km2), and also encompasses the rivers connecting them. In this case the total area is 220 km2.About 45% of the land surrounding the lake is natural landscape and 43.5% is agricultural land.HistoryLake Kasumigaura originally was a brackish-water lagoon, with indirect connections to the Pacific Ocean via the Hitachigawa and Tone Rivers. In 1963, the construction of a gate near the confluence of these rivers disconnected the lake from its sources of ocean water. As a result, the salinity of Lake Kasumigaura declined, and today the lake contains fresh water. This lake was famous for its traditional fishery during the Edo period. But today, fishing production has drastically decreased due to water quality deterioration that was partially caused by the closure of the tide gate in 1963 for purposes of desalination.UseToday, Lake Kasumigaura is used for fishing, irrigation, tourism, recreation, and for consumption by the surrounding public and local industry.