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The Aqueduct of the Gier (French ''Aqueduc du Gier'')〔It was called the ''Aqueduct of Pilat'' when Aubin-Louis Millin de Grandmaison visited it and inspected its dramatic remains in 1804 (Millin de Grandmaison, (tr.) ''Travels through the southern departments of France'' London, 1808:136f; the translator renders ''Pilat'' "Pila"〕 is an ancient Roman aqueduct probably constructed in the 1st century CE to provide water for Lugdunum (Lyon), in what is now eastern France. It is the longest and best preserved of four Roman aqueducts〔The others were the Mont d'Or, the Yzeron and the Brevenne aqueducts (L. Mays, ''Ancient Water Technologies'', 2010;132); the names, of course, are modern.〕 that served the growing capital of the Roman province of Gallia Lugdunensis. It drew its water from the source of the Gier, a small tributary of the Rhone, on the slopes of Mont Pilat, south-west of Lyon.〔Distance in James Stephen Bromwich, ''The Roman remains of Northern and Eastern France: a guidebook'' 2003:420; Bromwich gives detailed instructions for viewing sections of the aqueduct system.〕 Following a sinuous path, at the aqueduct of the Gier is the longest known of the Roman aqueducts. Its route has been retraced in detail, following the numerous remains. Leaving the uplands of the ''massif du Pilat'', department of the Loire, the aqueduct hugs the surface relief and crosses the department of the Rhone, passing through Mornant, Orliénas, Chaponost and Sainte-Foy-lès-Lyon to terminate at Lyon. In its extent, it draws upon the whole repertory of Roman techniques of aqueduct building, taking a slope that averages 0.1%, or a meter every kilometer. There are of covered ditches laid with a concrete culvert high and wide, which is sunk as deep as beneath the land surface. The aqueduct passes through 11 tunnels, one of which, near Mornant, is in extent. Access for cleaning and repairs was through manholes at distances. There are some thirty stretches in the open air. There are ten stretches raised on walls and arches, which provide the most spectacular visible remains of the aqueduct (''illustrations''). Four inverted siphon tunnels cross the particularly deep and wide river valleys of the Durèze, the Garon,〔Here the siphon drops 21 m, the length of the crossing 208 m (Jean Pierre Adam and Anthony Mathews, ''Roman Building: materials and techniques'', 2003:244).〕 the Yzeron and the Trion on pipe bridges raised on high arches. In these, water filled a sunken tank tower (''castellum''〔The parts of a Roman aqueduct are illustrated and explained in Peter J. Aicher, ''Guide to the aqueducts of ancient Rome'', 1995 and A. Trevor Hodge, ''Roman Aqueducts & Water Supply'', 2002.〕) on the brim of a slope. The tank effected a transition between open channel flow and a lead pipeline. From the ''castellum'' water was carried, now pressurized, in a set of airtight lead pipes laid side by side, with soldered joints, down the valley slope, across a bridge spanning the river—whose piers and arches are the most notable remains of the system—and up the facing slope, to a tank slightly lower than the head tank, losing just a little hydraulic head in the process. The inverted siphons obviated the bridging of deep valleys with arcade upon arcade of arches, as at Pont du Gard, which marks the limit of such a system. ==Date== The Gier aqueduct was built in a single great campaign, since no part of it could have served until it was completed; it must have taken years. The aqueduct of Giers was dated by Germain de Montauzon〔Montauzon, ''Les aqueducs antiques de Lyon'', 1909, refers to a Hadrianic inscription (''CIL'' XII 2494) at Chagnon, in effect a "no trespassing" notice to farmers who were in the practice of diverting water for irrigation. Within the limits Roman aqueduct zones were public property (Rabun Taylor, ''Public Needs and Private Pleasures: water distribution, the Tiber river and the urban development of ancient Rome'' 2000:57ff.〕 to the reign of Hadrian in the early 2nd century CE, but, as James Stephen Bromwich points out, its reticulated stonework (''opus reticulatum'') was characteristic of the later 1st century BCE and the first half of the 1st century CE, rather than of later masonry.〔Date revision was suggested by Jeancolas, ''JEAR'' 183, noted by Hodge 2002:435 note 10.〕 In addition he notes that a recently excavated public fountain on the hill of Fourvières, datable about 50 CE could not have been supplied with water until the Giers aqueduct was complete. 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「Aqueduct of the Gier」の詳細全文を読む スポンサード リンク
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