The city committed to construct a new "hydraulic factory" (in French ""usine hydraulique"") which would provide drinking water to the city and energy in the form of pressurized water for the operation of machinery. At the same time they embarked on the work necessary to regulate the level of Lake Geneva, notably by construction of a curtain weir across the river. The project as originally envisaged involved building the Bâtiment des Forces motrices on land administered by the then separate municipality of Plainpalais (later subsumed into Geneva) which was in financial difficulties. The therefore entered into negotiations to move the district frontiers in order to bring the proposed site within the Geneva city boundary. Plainpalais rejected the idea, however. It was therefore decided to reposition the site for the new building to an artificial island positioned in the middle of the river, after it had been agreed in 1882 that the river bed itself was part of Geneva. The river was divided into two parallel channels, called respectively the "Canal d'alimentation" (""Supply [of public drinking and fountain water] channel"") on the left side and the "Canal de régulation" (""Regulation [of the water level] channel"") on the right side. On the initiative of Jean-Daniel Colladon, the civil engineer Théodore Turrettini now embarked on a parallel career as a local politician, when he was elected to the . He went on to head up the construction project with energy and imagination. Before 1882 the level of the lake surface varied with the seasons, rising to it highest level at the end of the winter when the snows melted and the lake was filled by streams and torrents from the surrounding mountains. Work on the structure began in November 1893, when the level of the lake and the flow of water through it was expected to remain relatively low for the next five to six months. Along the part of the river where the powerhouse was built the river was separated into two parallel channels and these were drained successively in order to permit the construction of the building, the hydraulic structures and of a curtain weir attached to the located a few hundred meters upstream. Five Jonval turbines were installed in the small wing of the powerhouse crossing the river and commissioned in May 1886, producing a combined power of 900 kW. Two of the turbines supplied water pressure to what is today the city's old town, and the other three supplied surrounding districts, some of them as far as away.