sentences:  A number of dams were constructed in the early 20th century for flood control and power generation.In 1957, as part of a M-21 Grand River bridge replacement project, the mouth of the Thornapple and lower channel were relocated about 500 feet upstream on the Grand, and land that had been the site of Robinson's first home in Ada and trading post was inundated.Today the Thornapple is not a navigable waterway, and there is no commercial water transport on it.