 At the United States Geological Survey's stream gauge near New Ulm, 3.2 miles (5.2 km) upstream from the river's mouth, the annual mean flow of the river between 1909 and 2005 was 381 cubic feet per second (11 m³/s).The highest recorded flow during the period was 28,700 ft³/s (813 m³/s) on April 10, 1969.The lowest recorded flow was 0.5 ft³/s (0 m³/s) on November 27, 1952.