The river flows about 7 inches down hill for each linear mile of travel. The result is a very slow river. The water runs about 1.3-miles per hour in the headwaters region, picking up about 3 miles per hour downstream of the confluence with Ohio River. The National Park Service states that a rain drop falling into Lake Itasca at the headwaters will take about 90 days to flow past the Head Of Passes and into the Gulf of Mexico. If the river is 2,552 miles long, and the average flow is just over 2 miles per hour, math would suggest that the trip would take about 55 days. As it turns out, there are several large reservoirs on the upper river, and the river flows though some large lakes in northern Minnesota. The remaining 35 days of the trip would be spent in lakes, reservoirs, and dam pools.
The photo above is a view looking across the bridge from the west end. The photo below is a profile view from the west end of the bridge. Note that the bridge is slightly wavy due to the support piers being sunk into the marshy area near the river channel.