This 8 km long tunnel (with a 3m finished diameter) conveys clarified water from the Cham Asseman Dam to Baba Sheykh Ali water treatment plant.
The tunnel was originally part of a contract between the Esfahan RegionalWater Board and the Japanese company, Kumagai-Gumi. However, with the outbreak of the Iran – Iraq war, the Japanese company decided to evacuate its Japanese employees, and so decided to negotiate the completion of the work with Tablieh (already involved in the Cham Asseman Dam Project, next door). Tablieh successfully completed the project despite running into some weak geological formations that made the excavation with TBM impossible, thus having to change the excavation cross section from circular to horseshoe in order to enable the use of road headers instead.
