Gileppe Dam

Gileppe Dam
View from above in April 2007
Location of Gileppe Dam in Belgium
Official name	(French)
Location	Jalhay, Liège province, Wallonia, Belgium
Coordinates	50°35′21″N 5°58′28″E / 50.58917°N 5.97444°E / 50.58917; 5.97444Coordinates: 50°35′21″N 5°58′28″E / 50.58917°N 5.97444°E / 50.58917; 5.97444
Construction began	1868 (heightened 1967–71)
Opening date	28 July 1878
Construction cost	4,549,000 Belgian fr. ($874,000, £182,000)
Owner(s)	Wallonia
Operator(s)	Service public de Wallonie (SPW)
Dam and spillways
Type of dam	Gravity dam (masonry earth- and rockfill)
Impounds	Gileppe river
Height	1878: 51.76 metres Present: 68 metres
Length	365 meters
Width (base)	66 metres
Dam volume	248480.3 m3
Reservoir
Creates	Lake Gileppe
Total capacity	26,400,000 m3
Surface area	130 hectares
Power station
Turbines	two horizontal Francis-type
Installed capacity	0.633 MW
Annual generation	3.3 million kWh

The Gileppe Dam (French Barrage de la Gileppe) is an arch-gravity dam on the Gileppe river in Jalhay, Liège province, Wallonia, Belgium. It was built in the 1870s to supply water for the wool industry in nearby Verviers. The monumental structure with its unusually thick profile played an important role in establishing an international standard for masonry gravity dams as a technology for major water supply systems. It was considered one of the strongest dams in Europe at the time, and it was the first dam built in modern Belgium. In the first decade of the 21st century, it was noted as supplying most of the drinking water for Verviers, as well as industrial water, and as producing hydroelectricity.

In the 19th century, the dam was built to ensure the water supply for Verviers, the center of the wool industry in Belgium. Wool was imported through Antwerp and washed at Verviers, situated between the Ardennes and Belgium's Carboniferous region, before it was shipped for manufacture in Germany and Austria. Wool washing was facilitated by the high acidity of the water. Originally, the industry's water source was the Vesdre river, which proved to be insufficient; moreover, water was returned to the river so polluted that it destroyed the fish population and was blamed for the spread of malaria downstream. In the summer, when water levels were at their lowest, the industry faced shortages, and the local population relied on a limited supply of drinking water from springs. A dam was proposed, with studies to be undertaken by the engineer Bidaut. The goal was to provide the river Vesdre with about 3,000,000 cubic metres of water for the year, and 14,600,704 cubic metres to industry (8,808,000 gallons a day). After delays, a design was submitted in 1868 to the Minister of Public Works.