Lakes in the canton include : parts of Lake Lucerne , Lake Sarnen , Lungerersee , Wichelsee , Tannensee and Melchsee . Lakes in the canton include : parts of Lake Lucerne ( VierwaldstÃ ttersee ) , Lake Sarnen ( Sarnersee ) , Lungerersee , Wichelsee , Tannensee and Melchsee .