Depending
of the season the water flow of the Durance varies dramatically, from a low trickle of 20 m3/sec to a measured roaring maximum of
1700 m3/sec.
In the 19th century flash floods of the Durance caused great damage and a loss of many lifes.
Early plans for
a dam did not materialize but after WW II electricity demand grew and the huge potential for hydro electric power was recognized by
the French government.
Construction of a huge, earthquake-proof dam at Serre Poncon was started in 1957 and after
completion in 1959 it took the Durance 18 month to fill the reservoir.
When full the lake can hold 1.3 km3 of water with
a surface area of almost 28 km2.
The electric powerplant has 380 MW on its nameplate and the reservoir produces on average 700
GWh per year. The lake also provides irrigation to the hinterland.
Since the completion of the dam, Lac de Serre Poncon has developed
into a major summer tourist destination because of the beaches, watersport opportunities and the typical picturesque alpine
villages.
The surrounding mountains feature many hiking trails, sporting fantastic views of the lake from far above.