On June 21, 1804, William Clark wrote that the common water of the Missouri at that time contained half a common wine glass of ooze or mud to every pint. In the era of Lewis and Clark, the Missouri River was wild and unpredictable, earning the nickname Big Muddy because of its abundance of sand, sediment, silt, and clay. In a constant state of change, the river cut side channels, chutes, eddies, boils, sandbars, backwaters, and oxbows, with strong currents in some places and slow water in others. Flowing water cut into riverbanks, undercut shorelines, and felled trees into the moving water. Over time, the river meandered back and forth across the flood plain, touching the base of each bluff in tight serpentine curves. Sometimes these tight U-shaped curves pinched off, leaving an oxbow lake stranded from the river. Today the river is somewhat different, with channels maintained for navigation and flood control and dams farther upriver providing power generation, irrigation, recreation, and flood control.