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33-472: Ishioka is located in central Ibaraki Prefecture, approximately 70 kilometers north of central Tokyo. It is bordered by Lake Kasumigaura to the south and by mountains on all other sides. The urban area of the city is in the east. Ibaraki Prefecture Ishioka has a Humid continental climate (Köppen Cfa ) characterized by warm summers and cool winters with light snowfall. The average annual temperature in Ishioka

66-398: A ban on the use and sale of phosphate-containing synthetic detergents , and the control of nitrogen and phosphorus contents in the effluent 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). Brackish-water Brackish water , sometimes termed brack water ,

99-610: A natural defense against hurricane and tsunami damage in particular. The Sundarbans and Bhitarkanika Mangroves are two of the large mangrove forests in the world, both on the coast of the Bay of Bengal . Some seas and lakes are brackish. The Baltic Sea is a brackish sea adjoining the North Sea . Originally the Eridanos river system prior to the Pleistocene , since then it has been flooded by

132-526: A species only found in deep water in the Baltic, while pike are confined to the less saline surface waters. The Caspian Sea is the world's largest lake and contains brackish water with a salinity about one-third that of normal seawater. The Caspian is famous for its peculiar animal fauna, including one of the few non-marine seals (the Caspian seal ) and the great sturgeons , a major source of caviar . Hudson Bay

165-543: Is 13.8 °C. The average annual rainfall is 1331 mm with September as the wettest month. The temperatures are highest on average in August, at around 25.8 °C, and lowest in January, at around 2.8 °C. Per Japanese census data, the population of Ishioka peaked around the year 2000 and has declined since. During the Nara period , the provincial capital of Hitachi Province

198-549: Is a specific gravity of between 1.0004 and 1.0226. Thus, brackish covers a range of salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space or time. Water with a salt concentration greater than 30‰ is considered saline . See the salinity table from the Misplaced Pages salinity article . Brackish water condition commonly occurs when fresh water meets seawater. In fact,

231-544: Is a brackish marginal sea of the Arctic Ocean , it remains brackish due its limited connections to the open ocean, very high levels freshwater surface runoff input from the large Hudson Bay drainage basin , and low rate of evaporation due to being completely covered in ice for over half the year. In the Black Sea the surface water is brackish with an average salinity of about 17–18 parts per thousand compared to 30 to 40 for

264-719: Is the beautiful Kasumi freshwater pearls . 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 of paddy fields in the surrounding alluvial plain and upland fields on diluvial terraces covered by thick deposits of volcanic ash . The primary crops are rice and lotus root (a local speciality). Other crops include tomato , cucumber , eggplant , watermelon , corn , edamame , sweet potato , kabocha , daikon and peanut . Many tourists come to

297-418: Is used for fishing , irrigation , tourism , recreation , and for consumption by the surrounding public and local industry. A variety of fish can be caught from the waters of Lake Kasumigaura, including smelt , Japanese icefish , crucian carp , goby , Japanese eel and river prawn . The most popular catch is cultivated carp, followed by smelt and goby. Another cultivated treasure from Lake Kasumigaura

330-422: Is very low and the fish fauna consists predominantly of freshwater species such as roach , dace , carp , perch , and pike . The Thames Estuary becomes brackish between Battersea and Gravesend , and the diversity of freshwater fish species present is smaller, primarily roach and dace; euryhaline marine species such as flounder , European seabass , mullet , and smelt become much more common. Further east,

363-479: Is water occurring in a natural environment that has more salinity than freshwater , but not as much as seawater . It may result from mixing seawater (salt water) and fresh water together, as in estuaries , or it may occur in brackish fossil aquifers . The word comes from the Middle Dutch root brak . Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and

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396-449: The Eurasian 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 the prefectures of Ibaraki , Chiba and Tokyo . Eutrophication is a serious problem for Lake Kasumigaura. Legislation was enacted in 1982 to help prevent it, including

429-406: The crab-eating frog , Fejervarya cancrivora (formerly Rana cancrivora ). Mangroves represent important nesting sites for numerous birds groups such as herons, storks, spoonbills, ibises, kingfishers, shorebirds and seabirds. Although often plagued with mosquitoes and other insects that make them unpleasant for humans, mangrove swamps are very important buffer zones between land and sea, and are

462-526: The Ibaraki Prefectural Assembly. In terms of national politics, the city is part of Ibaraki 1st district of the lower house of the Diet of Japan . Ishioka has a diverse economy. Agriculture includes lotus roots , which are cultivated around Lake Kasumigaura, tobacco , and horticulture, such as persimmons, mandarin oranges , and strawberries cultivated at the foot of Mount Tsukuba . In addition,

495-479: The North Sea but still receives so much freshwater from the adjacent lands that the water is brackish. As seawater is denser, the water in the Baltic is stratified, with seawater at the bottom and freshwater at the top. Limited mixing occurs because of the lack of tides and storms, with the result that the fish fauna at the surface is freshwater in composition while that lower down is more marine. Cod are an example of

528-549: The city government, and three public high schools operated by the Ibaraki Prefectural Board of Education. There is also one private middle school and one private high school. [REDACTED] JR East – Jōban Line [REDACTED] Media related to Ishioka, Ibaraki at Wikimedia Commons Lake Kasumigaura Lake Kasumigaura ( 霞ヶ浦 , Kasumigaura ) is the second-largest lake in Japan , located 60 km to

561-490: The countryside is one of the leading rice areas in Ibaraki prefecture. Pig farming, chicken farming, and dairy farming are also major agricultural contributors. The city has an industrial park , with factories owned by Panasonic and Toyo Seikan, among others. Sake brewing is a traditional local industry, as is the manufacturing of incense sticks. Ishioka has 17 public elementary schools, eight public middle schools operated by

594-530: The flooding of coastal marshland to produce brackish water pools for freshwater prawn farming . Brackish water is also the primary waste product of the salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it can be damaging to the environment (see article on shrimp farms ). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more often expressed as 0.5 to 30 parts per thousand (‰), which

627-475: 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. Today, Lake Kasumigaura

660-587: The lake in the summer to view the Hobikibune (帆引き船) sailed fishing boats which are unique to Lake Kasumigaura. The Suigo aquapark , located in Tsuchiura , is popular during the hottest months. The windmill of Kasumigaura comprehensive park is a popular site along the shores throughout the year and especially in the spring when the tulips are flowering. The lake is a recreation hotspot. Sport fishing enthusiasts and anglers can be found close to shore and around

693-463: The most extensive brackish water habitats worldwide are estuaries , where a river meets the sea. The River Thames flowing through London is a classic river estuary. The town of Teddington a few miles west of London marks the boundary between the tidal and non-tidal parts of the Thames, although it is still considered a freshwater river about as far east as Battersea insofar as the average salinity

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726-419: The north-east of Tokyo . In a narrower sense and officially, Lake Kasumigaura refers to a waterbody with an area of 167.63 km . 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 km ) and Sotonasakaura (外浪逆浦; 5.85 km ), and also encompasses

759-537: The oceans. The deep, anoxic water of the Black Sea originates from warm, salty water of the Mediterranean . Lake Texoma , a reservoir on the border between the U.S. states of Texas and Oklahoma , is a rare example of a brackish lake that is neither part of an endorheic basin nor a direct arm of the ocean, though its salinity is considerably lower than that of the other bodies of water mentioned here. The reservoir

792-431: The pens the farmed fish are kept in. Another important brackish water habitat is the mangrove swamp or mangal . Many, though not all, mangrove swamps fringe estuaries and lagoons where the salinity changes with each tide. Among the most specialised residents of mangrove forests are mudskippers , fish that forage for food on land, and archer fish , perch-like fish that "spit" at insects and other small animals living in

825-553: The river mouths surrounding the lake. Recreational boats , such as yachts , power boats , sail boats and personal watercraft , are regularly enjoyed on warm weekends. The wide surrounding wetlands are wonderful for birdwatching , as large numbers of water 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

858-500: The river. This type of ecological succession from freshwater to marine ecosystem is typical of river estuaries. River estuaries form important staging points during the migration of anadromous and catadromous fish species, such as salmon , shad and eels , giving them time to form social groups and to adjust to the changes in salinity. Salmon are anadromous, meaning they live in the sea but ascend rivers to spawn; eels are catadromous, living in rivers and streams, but returning to

891-513: The rivers connecting them. In this case the total area is 220 km . About 45% of the land surrounding the lake is natural landscape and 43.5% is agricultural land. Lake 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

924-412: The salinity increases and the freshwater fish species are completely replaced by euryhaline marine ones, until the river reaches Gravesend, at which point conditions become fully marine and the fish fauna resembles that of the adjacent North Sea and includes both euryhaline and stenohaline marine species. A similar pattern of replacement can be observed with the aquatic plants and invertebrates living in

957-720: The sea to breed. Besides the species that migrate through estuaries, there are many other fish that use them as "nursery grounds" for spawning or as places young fish can feed and grow before moving elsewhere. Herring and plaice are two commercially important species that use the Thames Estuary for this purpose. Estuaries are also commonly used as fishing grounds and as places for fish farming or ranching. For example, Atlantic salmon farms are often located in estuaries, although this has caused controversy, because in doing so, fish farmers expose migrating wild fish to large numbers of external parasites such as sea lice that escape from

990-420: The trees, knocking them into the water where they can be eaten. Like estuaries, mangrove swamps are extremely important breeding grounds for many fish, with species such as snappers , halfbeaks , and tarpon spawning or maturing among them. Besides fish, numerous other animals use mangroves, including such species as the saltwater crocodile , American crocodile , proboscis monkey , diamondback terrapin , and

1023-510: Was created by the damming of the Red River of the South , which (along with several of its tributaries) receives large amounts of salt from natural seepage from buried deposits in the upstream region. The salinity is high enough that striped bass , a fish normally found only in salt water, has self-sustaining populations in the lake. Brackish water is being used by humans in many different sectors. It

Ishioka, Ibaraki - Misplaced Pages Continue

1056-472: Was created. Much of the town was destroyed in a fire on March 14, 1929. Ishioka was raised to city status on February 11, 1954. The new city annexed the neighboring villages of Mi and Sekigawa on December 1, 1954. On October 1, 2005, the town of Yasato (from Niihari District ) was merged into Ishioka. Ishioka has a mayor-council form of government with a directly elected mayor and a unicameral city council of 22 members. Ishioka contributes two members to

1089-455: Was located in what is now part of the city of Ishioka. The area was known as Hitachi-Fuchū ( 常陸府中 ) , or simply as “Fuchū” for most of history and developed as a castle town during the Edo period for Hitachi-Fuchū Domain . The domain was renamed “Ishioka Domain” in 1869. With the establishment of the modern municipalities system on April 1, 1889 after the Meiji restoration , the town of Ishioka

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