Note 89 — Chapter VI · THE PLAIN OF THE PAMPAS

The water problem is not as important for the history of colonization in the Pampean region as in the north. Primitive breeding was confined to natural supplies of water, lagoons or streams, and to shallow wells (jagueles) dug down to the superficial sheet, which is generally not deep, but is liable to dry up. As colonization improved, the breeder, and subsequently the farmer, were better equipped for boring wells, and no longer feared drought. They got down to the deeper waters, semi-artesian (Buenos Aires district) or artesian (west of the Santa Fé province, round San Francisco). In other places the superficial waters, which are fresher than the deeper layers, were used by adapting new types of filters to the wells (Buena Esperanza district). The only two districts where the quest of water offered any difficulty are the south-west corner of the Pampean region and the northern extremity of the prairie in the Sante Santa Fé province. The sheets of water are very irregular there, often saline, and it was a long time before the ranches got an assured supply.

One remarkable circumstance is the importance of the dunes in connection with the distribution of the underground water. The rain-water accumulates in the dunes and flows slowly through the sand to the sub-soil. The level of the underground sheet in the clay on which the dune rests is always nearer the surface in the neighbourhood of the dune. The dune itself has often a greener vegetation than the land around it. Nothing is more surprising than to find at Medanos (west of Bahía Blanca), in the middle of a plain of arid aspect, fields of lucerne and orchards lodged in the hollows of dunes that are still fresh. In the whole of the Buenos Aires province the dead district of the dunes is, on account of its water-supply, a good place for habitation. D'Azara notices the numerous water-spots which ran along the foot of the dead dunes of the Cerillada. All round were the white bones of the baguales. In the valleys of the central Pampa, where the sheet of water in the centre of the valley is often saline, the underground water improves gradually as one approaches the line of the dunes.