A dynamic force, the Mississippi River changes constantly. Humans have also changed the river, dramatically altering its flow and levels — sometimes with unintended results.
In its natural state, the river once flowed freely across a large floodplain — which included the trail that you are standing on now. The river habitat relied on this seasonal flooding, a key feature of a river's natural system.
Shaping the Land
Much of the Upper Mississippi River Valley was shaped around 15,000 years ago when the Wisconsin Glacier began to melt, increasing the flow of the Mississippi River. The force of the water carved the landscape as it traveled.
The river took a sharp turn to the east at Hastings around a hard wall of rock — the dolomite limestone bluff you see in front of you.
The Dam's Impact
The Hastings Dam, completed in 1930, created a reliably navigable channel, stabilized water levels, and eliminated seasonal fluctuations. The river is now wider above the dam.
But sediments, periodically flushed naturally in an open river system, now accumulate in greater amounts and ultimately diminish river water quality.