The Swiss architect and engineer, based in Zurich, presented four visions of a crossing over the lake to a Geneva transport department consultation committee earlier this month, reported La Tribune de Genève.
The committee has from now until September to consider whether a bridge or tunnel should form the basis of a new lake crossing, as agreed in principle by the people of Geneva in a referendum last year.
The crossing would aim to relieve traffic congestion through Geneva city centre by creating a full bypass loop.
The text of the referendum did not specify what form the crossing should take, but supporters suggested a bridge over the lake linked to a tunnel under the suburbs of the city at each side.
Calatrava has not received any official mandate from Geneva to design the crossing, but simply wanted to help by presenting his ideas to the committee, a spokeswoman told The Local.
The architect has a lot of experience in bridges and tunnels and thinks the Lake Geneva site is “extraordinary,” said the spokeswoman, adding that once he got started designing, “he couldn't really stop”.
Calatrava wanted to give his input “to help people imagine what can be done, what's feasible, taking into account the constraints,” she said.
One of Calatrava's images shows a suspension bridge, while the others show variations of a bridge/tunnel hybrid, with the bridge section popping out of the lake.
One of the four designs. Photo: office of Santiago Calatrava
Spanish-born Swiss architect Calatrava trained as a civil engineer at ETH Zurich and established his architectural and engineering practice in the Swiss city in 1981.
Since then he has completed projects all over the world, including many in Switzerland. Among his most famous works are the Montjuic communications tower in Barcelona, the City of Arts and Sciences in Valencia, a bridge over the Grand Canal in Venice and the World Trade Centre transport hub on the site of the 9/11 attacks.
The idea of a lake crossing has long been on the agenda in Geneva.
The principle was approved for the first time back in 1988 before voters rejected the idea of a bridge or tunnel in a further referendum eight years later.
Another tunnel project was rejected by voters in 2014.
Photo: office of Santiago Calatrava