5108 x 3399 px | 43,2 x 28,8 cm | 17 x 11,3 inches | 300dpi
Data acquisizione:
10 settembre 2009
Ubicazione:
Laos, Vientiane province, LAO
Altre informazioni:
Nam Ngum Reservoir is the largest water impoundment in Laos; it was created in 1971 by the construction of a dam 75m in height across the Nam Ngum River, about three km upstream from its confluence with the Nam Lik. The reservoir was conceived primarily for the production of hydro-electric power and flood control. It is fed by five rivers, the Nam Ngum, Nam Sane, Nam Ke, Nam Pat and Nam Xi, and many smaller streams rising in the surrounding hills. It overflows into the Nam Ngum River which joins the Mekong River about 60 km to the southeast. The impoundment created numerous small islands in five major island groups varying in size from about 75 ha to 500 ha. The timber was not removed from the basin before the closure of the dam and so the entire water surface is dotted with emergent dead trees. These are expected to persist for more than 100 years. Most of the shoreline is steep. The average depth at high water level is l9m, the level reaching its maximum in September or October and minimum in April to July. The average drawdown is about 10m and the maximum l6m. Some 4, 000 ha of lake bed are exposed for six months of the year, and 11, 000 ha during the three driest months.
