Durance river hydraulic development

Abstract

The river Durance, which flows into the river Rhone, collects heavy torrential rains and has a large gradient. These are excellent circumstances to make use of its water for irrigation purposes. The water flow varies between 45 and 6,000 m³/sec, and this has necessitated the building of control dams. Over the higher reaches the most important section is that of Serre Ponçon, which carries an average of 85 m³/sec. Beyond this dam, there are several others, such as Curbans and Oraison; the first of which provides a flow of 158 m³/sec, and drop in level of 77 m. The main water conduit at this dam has a large cross section, and its construction was preceded by a guide tunnel. Very modem high performance construction material was employed for this purpose, and the mean rate of progress was 9 m per day, in two shifts. The E. D. F. are the owners of this hydraulic enterprise, and they required from the contractors that this gallery should be lined with cement within two months of completing the excavation work. The Oraison dam takes its water from the Escale reservoir (capacity 3.5 million cubic metres), and there is a tunnel, 21 km long, to take the water to the pressure conduits of the underground power station.