Sarner Aa

The Sarner Aa is a small river in the canton of Obwalden, Switzerland. It is a tributary of the Lake Sarnen (Sarnersee). The river is formed by the confluence of several smaller streams in the Melchtal valley, flows through the village of Sarnen, and empties into the Sarnersee. The Sarner Aa plays a significant role in the local ecosystem and is used for hydroelectric power generation. Its drainage basin is largely composed of mountainous terrain and forested areas.