Tensfelder Au () is a river of Schleswig-Holstein, Germany. It springs north of the village of Blunk and then flows in a northeasterly direction through the town of Tensfeld and Hornsmühlen into the lake GroÃÂer Plöner See. After the Schwentine, the Tensfelder Au is the second largest river flowing into the GroÃÂer Plöner See.