Olarongchu is a stream that flows down from Dagala through Chamgang and passes from below Olakha village before it joins the Thimchu river. As the development picked up in the capital city of Thimphu, the fertile paddy field along the Olarongchu was developed into an automobile workship site and the automobile workshops were shifted to the site from Changzamtok in 2008. Today the site along the Olarongchu is a hub of automobile workshops.