The Ume River flows through the lake and has a maximum depth of 148 metres (486 ft).

The approximately 30-kilometre (19 mi) long northwestern part is narrow and winding and is surrounded by 400–500-metre (1,300–1,600 ft) high, steep mountainsides.

The lake is also a water reservoir for the hydroelectric power plants on this river, with a difference of up to 7 metres (23 ft).

The 30 km (19 mi) long northwestern part is narrow and winding between steep mountain slopes up to 500 metres (1,600 ft) high.

The southeastern part is up to 6 km (3.7 mi) wide and has relatively flat banks and sandy peninsulas.