The river has its source in the central Tien Shan, at the confluence of the Tekes and Kunes41 rivers. The Kash, Saryn and Silik are other tributaries to the Hi. In flowing into Lake Balkhash, it forms a vast delta on Kazakh territory (see the assessment of the Hi delta). In Kazakhstan, the flow is regulated at the Kapchagai Reservoir, which is used for irrigation, drinking water supply, and hydropower production.