 Complete the following phrase:  The U.S. Geological Survey USGS operates five stream gauges along the river, at Harrisburg, Corvallis, Albany, Salem, and Portland. The average discharge at the lowermost gauge, near the Morrison Bridge in Portland, was between 1972 and 2013. Located at river mile RM 12.8 or river kilometer RK 20.6, the gauge measures the flow from an area of , roughly 97 percent of the Willamette basin. The highest flow recorded at this station was on February 9, 1996, during the Willamette Valley Flood of 1996, and the minimum was on July 10, 1978. The highest recorded flow of for the Willamette at a different gauge in Portland occurred during a 