The River La Thielle ("Zihl") is a tributary to the Aare River, in the Swiss Seeland.
"La Thielle" results of the merging of the river Orbe and river Talent, Northeast of the little city of Orbe in the Swiss Canton of Vaud. La Thielle flows as a channel toward Northeast through an intensive cultivated plain called "Plaine de l'Orbe" and flows already after 9 km into the Lake of Neuchâtel in Yverdon-les-Bains.
During the Jura water correction, the natural course of the river has been sizably modified. Between the Lakes of Neuchâtel and Biel/Bienne it has been laid into a dug-out channel. However, the previous natural bed of La Thielle still exists in some parts.
The river flows out of the lake in Biel/Bienne and merges upon 2 km directly into the Nidau-Büren channel, which was also dug out during the Jura water correction, ensuring the outflow of River Aare, just before the regulating dam in Port which was commissioned in 1939. Before, La Thielle used to merge with River Aare 7 km further downstream in the vicinity of Büren-an-der Aare.
In the Seventeenth Century, a grand project existed to establish a naval transportation waterways system connecting the Rhône and Rhine Rivers via Lake of Geneva - the River Venoge - and the Canal d'Entreroches - La Thielle - Aare. It has unfortunately remained unfinished.
This system of commercial waterways would have had a very significant impact on the European commercial transportation system.|