| Lake Kasumigaura 霞ヶ浦 | |
|---|---|
 The Landsat satellite picture of Lake Kasumigaura. | |
  Lake Kasumigaura 霞ヶ浦 | |
| Coordinates | 36°2′25″N140°23′39″E / 36.04028°N 140.39417°E /36.04028; 140.39417 |
| Type | warmMonomictic |
| Primary inflows | Sakura and Naka rivers and more than 30 small rivers |
| Primary outflows | Tone River |
| Catchment area | 1,915 km2 (739 sq mi) |
| Basin countries | Japan |
| Surface area | 220 km2 (85 sq mi) |
| Average depth | 4 m (13 ft) |
| Max. depth | 7 m (23 ft) |
| Water volume | 0.848 km3 (687,000 acre⋅ft) |
| Shore length1 | 252 km (157 mi) |
| Surface elevation | 0.16 m (6.3 in) |
| Islands | 0 |
| Settlements | Tsuchiura, Ibaraki Kasumigaura, Ibaraki |
| 1 Shore length isnot a well-defined measure. | |
Lake Kasumigaura (霞ヶ浦,Kasumigaura) is thesecond-largest lake inJapan, located 60 km to the north-east ofTokyo.
In a narrower sense and officially, Lake Kasumigaura refers to awaterbody with an area of 167.63 km2.[1][2] In a wider sense, Lake Kasumigaura can also refer to a group of contiguouslakes, which includes Lake Kasumigaura proper, hereby referred to as Nishiura (西浦), and two smaller lakes, Kitaura (北浦; 35.16 km2[1][2]) and Sotonasakaura (外浪逆浦; 5.85 km2[1][2]), 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.
Lake Kasumigaura originally was abrackish-waterlagoon, with indirect connections to thePacific 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 traditionalfishery during theEdo period. But today, fishing production has drastically decreased due towater qualitydeterioration that was partially caused by the closure of the tide gate in 1963 for purposes of desalination.[3]
Today, Lake Kasumigaura is used forfishing,irrigation,tourism,recreation, and forconsumption by the surrounding public and local industry.
A variety of fish can be caught from the waters of Lake Kasumigaura, includingsmelt, Japaneseicefish,crucian carp,goby,Japanese eel andriver prawn. The most popular catch is cultivated carp, followed by smelt and goby. Another cultivated treasure from Lake Kasumigaura is the beautiful Kasumi freshwaterpearls. They were known for their high luster and rosy hues, which is the result of a four-year cultivation period. However, in 2006, cultivation was discontinued as cheap freshwater pearls from China proved too difficult to compete against.
The water from Lake Kasumigaura has long been used for the irrigation ofpaddy fields in the surroundingalluvial plain and upland fields ondiluvial terraces covered by thick deposits ofvolcanic ash. The primary crops arerice andlotus root (a local speciality). Other crops includetomato,cucumber,eggplant,watermelon,corn,edamame,sweet potato,kabocha,daikon andpeanut.
Many tourists come to the lake in the summer to view theHobikibune (帆引き船)sailedfishing boats which are unique to Lake Kasumigaura. The Suigoaquapark, located inTsuchiura, is popular during the hottest months. Thewindmill of Kasumigaura comprehensive park is a popular site along the shores throughout the year and especially in the spring when thetulips are flowering.
The lake is a recreation hotspot.Sport fishing enthusiasts andanglers can be found close to shore and around the river mouths surrounding the lake.Recreational boats, such asyachts,power boats,sail boats andpersonal watercraft, are regularly enjoyed on warm weekends. The wide surroundingwetlands are wonderful forbirdwatching, as large numbers ofwater fowl can be observed, primarily during the wintering period.Japanese cormorant,Bewick’s swan,little egret,grey heron,mallard,Eurasian wigeon,striated heron,sharp-tailed sandpiper,bush warbler,wood sandpiper,marsh grassbird,Japanese reed bunting, and theEurasian coot are a few of the birds seen around the lake.
Lake Kasumigaura provides over 60 tons of water per second; most goes to agriculture (83%). The rest is provided to local industry (13%) and public (4%) in theprefectures ofIbaraki,Chiba andTokyo.
Eutrophication is a serious problem for Lake Kasumigaura. Legislation was enacted in 1982 to help prevent it, including a ban on the use and sale of phosphate-containing syntheticdetergents, and the control of nitrogen and phosphorus contents in theeffluent from factories.
In order to help maintain the lake, dredging work is being carried out around the lake and at the estuaries of main inflowing rivers, such as Sakura River (桜川).
| International | |
|---|---|
| National | |
| Other | |
