The Roendahl Canyon is located in the upstream region of the River Mais east of Mellvere.
In ancient times the River Mais often flooded, causing great damage to cities downstream. Now water levels are controlled using the dams and flood gates built in the canyon. It recently became known that the frequent flooding of the River Mais was largely due to excessive timber logging in the middle ages, reducing the water-holding capacity of the surrounding area. The government is now considering a replanting program.