In 1870, a stone dam and an iron bridge was built on the Big Blue River. A hydroelectric power plant was added. It would provide power for manufacturing and for the town. The power plant was destroyed by a flood in 1903. In the late 19th century and early 20th century there were four gypsum mines in the area. Around 1910, more than 1,750 people lived in Blue Rapids. The public library was built in 1875. It is the oldest library west of the Mississippi that is still being used in the same building.