The Grand River is on a 100 year flood cycle. History. The Grand River once served as a transportation route and was essential to the establishment of the local furniture industry, as loggers floated their harvest down the river.The people who were here just before the Europeans arrived in this thriving trading encampment called the river the "O-wash-ti-nong". The river flows through a swath cut by the retreating glaciers from the last Ice Age. The river had many boulders of Limestone and Granite; these made for swift currents and an ever-changing bottom riverscape. The river was a source of life from the eating of aquatic foods and sometimes, for non-swimmers, death. When European settlers came to know the river's power, resources, and great expanse they wanted to give it a fitting name in their own language: they decided it should be called the Grand River. Today the Grand River is still the longest river in Michigan, flowing through Jackson, Lansing, and Grand Rapids before flowing into Lake Michigan at Grand Haven. It flows south through the city of Grand Rapids and serves as a visual and physical boundary between downtown and the west side. Do not be deceived, however, when addressing your mail to buildings on the east bank of the Grand River, for the west side actually extends into the eastern bank areas of the city for a little way. The Grand River is on a 100 year flood cycle.