Carex riparia is together with Carex acutiformis and Carex acuta one of the three more common large sedges of wet habitats. The arc of the ligule of the lower leaves is blunt. The central male spike is by far larger than the lateral ones. The subtending bract of the lowest spike is leaf-like and longer than the spike itself. Female flowers have three stigmas. The utricles have two distinct teeth at the top. The female glumes are reddish-brown and usually bear an awn.