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28-486: Some of its length (40 ha area) is also classified as an Important Bird Area (TN013) as the cavities and holes in the aqueduct are used as nesting and roosting sites for falcons and other species. The date of the construction of the aqueduct is not entirely clear. Sources mention a visit by the Emperor Hadrian in 128, with which a five-year-long drought is meant to have come to an end. The water shortage resulting from

56-439: A 4-metre-wide (13 ft), crescent-shaped portico. In the center of the portico is a cella from which the spring sprang. The outer wall had a core of Roman concrete covered with coarse limestone bossages . This wall continued from the ends of the crescent-shaped portico and was divided into 26 sections be engaged columns. In every second section, there is a niche for statues, which do not survive. Opposite each engaged column

84-474: A population of a species categorized by the IUCN Red List as Critically Endangered , Endangered or Vulnerable . In general, the regular presence of a Critical or Endangered species, irrespective of population size, at a site may be sufficient for a site to qualify as an IBA. For Vulnerable species, the presence of more than threshold numbers at a site is necessary to trigger selection. The site forms one of

112-420: A second source was attached to the aqueduct. This was located in the region of Djouggar. A sacred fountain was built over this spring too, but it never reached the significance of the one at Zaghouan. The aqueduct is a masterpiece of Roman engineering. In the journey from Zaghouan to Carthage, it travels a little over 90 km and drops only 264 m in height, which is an average decline of 0.3%. However, 130 m of

140-429: A set selected to ensure that all restricted-range species of an Endemic Bird Area (EBA) or a Secondary Area (SA) are present in significant numbers in at least one site and preferably more. The site forms one of a set selected to ensure adequate representation of all species restricted to a given biome, both across the biome as a whole and for all of its species in each range state. The assessment by expert individuals

168-463: Is a form of Roman concrete ( opus caementicium ), the main difference being the addition of small pieces of broken pot, including amphorae , tiles or brick, instead of other aggregates. Its main advantage over opus caementicium was that it is waterproof, the reason for its widespread use in Roman baths , aqueducts, cisterns and any buildings involving water. In floors it provided damp-proofing. Pliny

196-452: Is a full column, which together once supported a vaulted peristyle. The vaults are made of porous travertine covered in marble , while the columns are sandstone . The exterior of the vault was sealed with waterproof Opus signinum and left without further protection. The floor of the portico was decorated with mosaic . The cella, the most important part of the building was built from limestone and clad in marble. There were five springs in

224-409: Is an area identified using an internationally agreed set of criteria as being globally important for the conservation of bird populations. IBA was developed and sites are identified by BirdLife International . There are over 13,000 IBAs worldwide. These sites are small enough to be entirely conserved and differ in their character, habitat or ornithological importance from the surrounding habitat. In

252-593: Is completely lacking. In 1985, following a specific request from the European Economic Community , Birdlife International drew up a list of sites to be protected as a matter of priority. In 1989, a repertoire of IBAs of Europe was released. At first the official name of this type of site was Important Bird Area , hence the acronym IBA, then at the BirdLife World Congress held in Canada in 2014 it

280-468: Is however not entirely reliable and a study in South America found that the coverage needed for at-risk bird conservation as chosen by computational algorithms rarely overlapped with IBAs and suggested that such methods should be used to complement expert driven IBA site choices. Opus signinum Opus signinum ('cocciopesto' in modern Italian) is a building material used in ancient Rome . It

308-457: Is located near the town of Zaghouan in the Djebel Zaghouan , a mountain range about 60 km south of Carthage. In Roman times a sacred fountain structure was built over the spring, which became one of the most important in ancient North Africa. The sacred fountain is located on an artificial terrace. It is open on the north side, and on the southern side there is an open space enclosed by

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336-572: The Arabs in 698, but each time it was subsequently restored. In the thirteenth century, one of the Hafsid rulers added a branch leading to his palace in Manouba in order to supply water for his garden. From the sixteenth century, the aqueduct deteriorated rapidly and was employed as a stone quarry. In 1859 a French engineer received the task of restoring the water channel in order to supply Tunis with water. While

364-513: The lesser kestrel Falco naumanni (30 pairs), but also by the Lanner falcon Falco biarmicus and the common kestrel Falco tinnunculus as well as the European roller Coracias garrulus , rock sparrows Petronia petronia , spotless starlings Sturnus unicolor and common ravens Corvus corax . The site is of particular significance for the lesser krestel as it regularly holds significant numbers

392-560: The Baths of Antonius. The construction date is unknown, but modifications have been detected in connection with the construction of the Baths of Antonius, implying that the cistern preceded the baths. Since the water supply was essential for the city, the aqueduct was destroyed during the Vandal siege of 439, the Eastern Roman reconquest under Justinian and finally at the conquest of Carthage by

420-507: The Elder describes its manufacture: Even broken pottery has been utilised; it being found that, beaten to powder, and tempered with lime, it becomes more solid and durable than other substances of a similar nature; forming the cement known as the Signine composition, so extensively employed for even making the pavements of houses. Pliny's use of the term signine references Signia (modern Segni ),

448-533: The United States the program is administered by the National Audubon Society . Often IBAs form part of a country's existing protected area network, and so are protected under national legislation. Legal recognition and protection of IBAs that are not within existing protected areas varies within different countries. Some countries have a National IBA Conservation Strategy, whereas in others protection

476-407: The area of the sacred fountain. These were in the area of the artificial terrace in their original, underground bed and gathered in a basin under the terrace. From this basin, the water then flowed into the pipe of the aqueduct. As well as feeding the aqueduct intake, the basin also served to clean the water - while the water sat in the basin, impurities would settle on the bottom. In Severan times,

504-436: The channel follows the contours of hills. In three places it was not possible for the channel to remain at ground level, so the engineers erected imposing arcades . They are: In cross-section, the channel measures about 90 cm in width and 130 cm in height. It was closed on top by a vault. The walls were made from Roman cement and were clad with sandstone bossage. The part of the channel which came in contact with water

532-653: The drought might have convinced him that the people should not rely only on rainwater anymore. A second event that might have inspired it was the opening of the Baths of Antonius in Carthage in 162. These facilities on the same scale as the Imperial baths in Rome demanded a steady supply of water, which could not be fulfilled with rainwater. The aqueduct draws on several sources which ran dry at different times. The first and most important source

560-545: The height difference occurs in the first 6 km from Zaghouan to Moghrane. For the rest of the journey to Carthage, the decline averages only 0.15%. In Moghrane the aqueduct met the later channel coming from Djouggar, another 33 km away. Including all its tributary channels, the aqueduct has a length of 132 km and is among the longest in the Roman empire. The channel discharged between 200 and 370 L of water per second or between 17 and 32 million liters per day. The flow rate

588-416: The majority of the channels at ground level could be reused, the parts of the channel on pillars were mostly destroyed and a modern pressure pipe system was installed. Since it was put into operation in 1862, the channel has remained in use and today it supplies an average of 12,000,000 L per day in winter and 3,000,000 in summer. The cavities and holes in the aqueduct are used as nesting and roosting sites by

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616-413: The nature of the mortar , they are dated to the first century AD. It is not yet clear how these cisterns were used in that period, since the aqueduct had not yet been built and this enormous volume could never have been filled by rainwater alone. The cistern of Bordj Djedid is made up of 18 barrel-shaped basins arranged in parallel and held between 25 and 30 million liters. It was responsible for supplying

644-493: The species, (which is a species of global conservation concern). The protected area extends over 40 ha as a band stretching near the Milliana river along the aqueduct 20-m-high pillars and arches in which many cavities and holes used by birds have developed. The surrounding area consists of cereal fields and is a hunting reserve. General Specific Important Bird Area An Important Bird and Biodiversity Area ( IBA )

672-734: The town in Latium which was famous for its tiles. The technique, most probably invented by the Phoenicians, is documented in the early 7th cent. BC at Tell el-Burak (Lebanon), then in Phoenician colonies in North Africa, some time before 256 BC, and spread north from there to Sicily and finally to the Italian peninsula . Floors of signinum are found extensively in the Punic towns of North Africa and commonly in

700-409: The water within Carthage is not yet entirely clear. It seems that the channel discharged into two cisterns and the water was further distributed from these. To date, however, archaeological excavations have found no sure signs of discharge into the cisterns. The cisterns of La Malga form the largest cisterns surviving from the ancient world anywhere. They held approximately 51 million liters. Based on

728-502: Was around 3.5 and 5.5 km per hour. Therefore, the water made the journey from Zaghouan to Carthage in between a day and a half, to two days. The channel was built such that it had a steady, if not uniform, fall so that the water would travel the route by the force of gravity alone. In order to minimize the building work, the channel was laid on or a little under the Earth's surface where possible. In order to avoid unnecessary loss of height,

756-408: Was decided to adopt the name Important Bird and Biodiversity Area , without changing the acronym. IBAs are determined by an internationally agreed set of criteria. Specific IBA thresholds are set by regional and national governing organizations. To be listed as an IBA, a site must satisfy at least one of the following rating criteria: The site qualifies if it is known, estimated or thought to hold

784-468: Was further clad in waterproof opus signinum . The screed also served to smooth the channel's rate of decline. Ventilation was provided by small, square openings in the roof. At regular intervals on the base of the channel, there were circular depressions, which served to purify the water, since detritus would settle in them. To continue to operate, these had to be cleaned out regularly, so the channel required ongoing care and attention The distribution of

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