Barragens romanas do distrito de Castelo Branco e Barragem de Alferrarede

Abstract

The dams vestiges in the district of Castelo Branco. attributed by the authors to the Romans, are described and the original characteristics of those dams are reconstituted, Two post-Roman dams, probably built in sixteenth century, are also describecl: - the Penamacor masonry clam, from which there are no vestiges. whose notice results on ly from bibliography; - the 13 m high Alferrarecle dam, with two Illasonry walls and an earthfi ll core. which remains in a fairly goocl condition. From the eight clams atributed to the Romans, two were built in Illasonry ancl six in earthfi ll. The earthfill dams cio not seem to have been proviclecl with spillways ancl outlets. The vestiges of each of these clams consist of two earthfill reaches separatecl by a gap. which, nowadays, allows the water to passo Some of those earth clams were important structures which illlpliecl the movement 01' large alllount of earthfill and the use of aclequate compactation technics, as shown by the geotechnical charateri zati on. The most important dams are those of Egitani a and Lameira, with he ights of II and 9 m and an earthfill volume of 12000 and 16000m3, respecti vel y. The earth dams studied in thi s work were or great importance within the Roman World , considering the scarcity of comparable earth structures (without a masonry wall ). The dams were attributed to the Roman period in the bas is of the fo llowing fac ts: - ex istence of Roman vestiges in the ne ighbourhood of five dams; - dam construction types analogies; - reference to Orca dam in a document of the year 1505 ; - hi story of the country occupation in post-Roman period; - hi story of dam construction in Europe. The purpose of the most of studied dams was, very probabl y, the water supply to gold mining, because, at least, one of the fo llowing situati ons occurs for each dam: - non-ex istence of vil/ae downstream of the dams; - absence of connecting channe ls vestiges between the dams and the roman habitats downstream, whenever ex istent ; - non-ex istence of appropriated soil s to irri gation, downstream of the dams. - ex istence of springs that were surely used to supply water to villae, located near the dams; the use of nearby springs and well s was also possible in other sites. The Roman occupation of the country and name ly the gold mining acti vity are documented by the bibliography and the discovery of many treasures Uewels and coins) proves the accumulati on of wealth as result of gold mining acti vity.