|
Water supply and sanitation in Gibraltar have been major concerns for its inhabitants throughout its history, from medieval times to the present day. The climate of Gibraltar is a mild Mediterranean one with warm dry summers and cool wet winters. Since daily records of rainfall began in 1790, annual rainfall has averaged a mean of with the highest volumes in December and the lowest in July.〔Rose (2001), p. 112〕 However, most of Gibraltar's small land area is occupied by the Rock of Gibraltar, a limestone outcrop that is riddled with caves and crevices.〔Sawchuk, p. 131〕 There are no rivers, streams, or large bodies of water on the peninsula, which is connected to Spain via a narrow sandy isthmus. Gibraltar's water supply was formerly provided by a combination of an aqueduct, wells, and the use of cisterns, barrels and earthenware pots to capture rainwater. This became increasingly inadequate as Gibraltar's population grew in the 18th and 19th centuries; the settlement was a breeding ground for lethal diseases such as cholera and yellow fever, which killed thousands of its inhabitants and members of the British garrison in repeated outbreaks. In the late 19th century, a Sanitary Commission instigated major improvements which saw the introduction of large-scale desalination and the use of giant water catchments covering over 2.5 million square feet (nearly 250,000 m2). Today Gibraltar's supply of drinking water comes entirely from desalination, with a separate supply of saltwater for sanitary purposes – both supplies are delivered from huge underground reservoirs excavated under the Rock of Gibraltar. ==Under Moorish and Spanish rule== Gibraltar was uninhabited during ancient times due in part to a lack of easily accessible water to support a permanent population,〔Jackson, p. 22〕 but in the 11th century the Moors established a fortified stronghold there in response to military threats from the Christian kingdoms of Aragon and Castile.〔Hills, p. 13〕 The Moors obtained water through roof catchment of rainfall, shallow wells in the Quaternary sands to the west of the Rock of Gibraltar, and storing local surface runoff in cisterns.〔Rose (2000), p. 248〕 In the 14th century they constructed an aqueduct that collected water from the Red Sands, an area south of the town in the vicinity of what is now the Gibraltar Botanic Gardens, and transported it some to a fountain within the town.〔Sawchuk, p. 134〕 Fountain Ramp, on the western side of John Mackintosh Square, preserves in its name the location of the aqueduct's original terminus.〔Rose (2004), p. 244〕 After the Crown of Castile conquered Gibraltar in the 15th century, the aqueduct was renovated and a pair of reservoirs was constructed around 1694.〔Rose (2000), p. 248〕 A medieval reservoir, Nun's Well, still survives at Europa Point in the far south of Gibraltar, though it is unclear who built it and when. When Thomas James saw it in the 1770s, he recorded that it was infested with leeches. This caused problems for the soldiers who had to drink the water, as the leeches attached themselves to the soldiers' tongues "and sucking for sustenance, caused the discharge of blood, which ... frightened some of the men not a little."〔James, p. 327〕 The only other source of freshwater was from wells bored into the isthmus with Spain, which produced non-potable water.〔 During the 19th century, the public could draw water for a fee but this supply was taxed by the British. A few dwellings, mainly those occupied by British officials, had their own private wells. However, most of the population had to rely on the public wells, from where they drew water which they carried back into the town. The water level gradually receded during the dry summer months, and sometimes it dried up altogether if precipitation during the year had been lower than usual.〔Sawchuk, p. 135〕 Historical sources conflict on exactly how much groundwater was available in Gibraltar. A 17th-century Spanish writer, Alonso Hernández del Portillo, asserts that "the city contained many tides and fountains of very sweet and healthy water" and that "fountains of fresh water could be seen spouting out of the sea near the foot of the Rock", possibly referring to a spring at a fault called the Orillon (at the site of the later Orillon Batteries) in the north-west face of the Rock. By the mid-19th century, however, the British writer Frederick Sayer was reporting that "there are no springs of pure fresh water"; the supplies from the few shallow wells that did exist would have been brackish at best. What is certain, however, is that by Sayer's time the existing water supplies were increasingly inadequate as Gibraltar's civilian population increased rapidly.〔Rose (2000), p. 250〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Water supply and sanitation in Gibraltar」の詳細全文を読む スポンサード リンク
|