Geographically, our area is located between the Capitanata, the Adriatic Sea, Basilicata and the plain of Bari. From the point of view of altitude, the territory ranges from the medium heights of the tableland of the Murgia (500-600 m above sea level) down to the sea. The hills (with heights varying from 400 to 90 m above sea level) slope down to the sea, joining the current beaches by means of slightly inclined plains, made of old marine terraces with a SE-NW orientation, that is, parallel to the coastline, while the connection between the morphological structures of the hills and the alluvial terraces of the Ofanto River is made with an unexpected change in incline.
The predominant topographical aspect of the territory is intermediate between the calcareous Murgian tableland and the hills that face the coastline. The territory towards the sea is characterised by numerous level areas, sometimes of notable expanse, which derive from the phenomenon of marine regression. These plateaus are, at times, densely cut into by deep valleys, having, at the top, very steep walls, and, at the bottom, less dramatic inclines. Corresponding to this altimetrical trend are very interesting lithological formations, in particular the limestone of Bari (found close to the coast and on the Murgia) and the calcareous formations at Gravina (tufa, a material that is porous and easy to work with, which is, along with the stone of Trani, the traditional material for construction in these zones) which are found particularly in the inland cities (Canosa, Andria and Corato). The extraction and working of the stone of Trani and of Minervino and of the tufa of Canosa are the pride of our tradition and current productive resources.
In general, the whole territory, and in particular the table land of the Murgias, is marked by imposing karstic phenomena. The rain waters, rich in carbon dioxide, with the work of millenia, have melted the limestone and created a spectacular phenomenon of erosion and the formation of an infinity of subterranean cavities. Fractures, abysses, gorges, karstic sink-holes, karstic basins, swallow holes, and flood grounds are the most evident signs of these extraordinary natural transformations.
The dolines or basins are depressions, generally of a truncated cone shape, with a flat bottom. They were formed by the collapse of the covering of gigantic karstic grottoes. Of note is the Gurgo, located near the Sanctuary of the Holy Saviour of Andria, one of the largest epigeous karstic structures in Puglia. The flood grounds are deep, paleo-torrential incisions that flow in a N-W direction, towards the Ofanto River and in a N-E direction, towards the sea. They are currently almost always dry, have slightly upward sloping sides and a sub-hill bottom, are often cultivated and are, in any case, dense with spontaneous vegetation.
Many flood grounds cross the territory of the cities of the Pact, and they have always led the waters of the meteorological precipitation of the Murgian high ground to the sea. The principal one is surely the Camaggi Flood Ground, seat of the ancient Aveldium River, cited by the ancients as the most important river after the Ofanto. Andria was built in the shelter of its bends. The Aveldium (controlled by the current Ciappetta-Camaggi Canal) originates near Castel Del Monte and reaches the sea at Ariscianno, between Barletta and Trani. Definitely worth seeing are: the flood ground located between Bisceglie and Trani (which before flowing into the sea near the valuable Olivieri Tower, which dates back to the 1500's, crosses a few ancient caves and flows past the ancient and mysterious little church of Saint Mary of Giano); the Saint Margaret Flood Ground (which laps Andria's sanctuary of the Madonna of the Miracles) where an important settlement of Basilian monks was developed, entirely in a grotto on the floor of the flood ground.