The Missouri River Trench is the geological name applied to the broad valley of the Missouri River as it flows southward through North Dakota and South Dakota in the United States.
The valley averages approximately 1 mi (1.6 km) wide, with the valley floor averaging between 300-600 ft (90-180 m) below the surrounding bluffs. The valley was extensively dammed between 1946 and 1966 to provide a series of reservoirs in the Dakotas. Geologically, the valley separates the main plateau of the Great Plains to the west from the Coteau du Missouri to the east.
Although cultivation has added markedly to the sediment in the river as it flows through the valley, the water was turbid even before the widespread introduction of agriculture, according to early European travellers. Erosion and deposition are believed to be in equilibrium in the trench. Siltation now provides a major challenge for the impounded sections of the river in the valley.
Famous quotes containing the words missouri river, missouri, river and/or trench:
“Then they seen it, the old Missouri River shinin’ in the moon and across it the lights of St. Louis.”
—Dudley Nichols (1895–1960)
“The traveller on the prarie is naturally a hunter, on the head waters of the Missouri and Columbia a trapper, and at the Falls of St. Mary a fisherman.”
—Henry David Thoreau (1817–1862)
““I’ll love you dear, I’ll love you
Till China and Africa meet,
And the river jumps over the mountain
And the salmon sing in the street.”
—W.H. (Wystan Hugh)
“Lord, what a change within us one short hour
Spent in Thy presence will avail to make!”
—Richard Chenevix Trench (1807–1886)