Insight about the catchment of the ancient Triglio aqueduct

Abstract

di Ilenia Argentiero*, Maria Dolores Fidelibus**, Roberta Pellicani*, Giuseppe Spilotro*
* Università degli Studi della Basilicata
** Politecnico di Bari

Abstract:
Near Taranto (Southern Italy), alongside the deep Triglio canyon and its branches, there is a huge ancient aqueduct. The
water intake apparatus is a hypogeum stretch for water interception formed by tunnels converging in a single pipe and
spanning about 4 km. Tunnels, mainly dug into calcarenites, drain the surrounding vadose zone fed by delayed infiltration
of precipitation, small overlying superficial aquifers at the top of canyon flanks, or alluvial deposits covering the
canyon bottom. Early hydrogeologists who designed the intake work were able to select the most permeable levels, only
today clearly identified with advanced hydrogeological knowledge. Tunnels and pits, in fact, locate between 130 and
170 m asl: this elevation range represents one of the specific elevation ranges recently ascertained in the carbonate platform
of Murgia as marks of prolonged sea level stands. There, sea level standstills over a geological timescale defined
groundwater levels, which in turn shaped karst planes inland on platform surface and karstified sub-horizontal levels
in subsurface. The sea carved abrasion surfaces on the Adriatic border of carbonate platform and shaped terraces in
coarse sediments on the opposite Ionian border, then forming modest aquifers on clayey beds. The geo-archaeological
studies highlight the role of early hydrogeologists, forerunners of an environmental culture that led to the construction
of an engineering masterstroke. The sophisticated work of Triglio recalls the qanat or foggare, heritage of Persian, Arab
and North African culture. The water intake work, currently is ascribed to the Roman period, but it is in the present
configuration the sum of several works dating a wide period, probably starting later, from the local Arab period, around
900 AD. The cultural relevance and the ecological efficiency of the work would need new more accurate historical, archaeological and hydrogeological studies.