Bridges over the Cedar River at Williamston evolved with the village's growth, from an early wooden bridge that carried supplies and traffic between mills and farms on the north side to a notoriously unsafe structure criticized in an 1873 Williamston Enterprise article as dangerous, badly neglected, and in urgent need of replacement. In 1877, a publicly funded bridge was built through the village's sale of $2500 in bonds. By 1902, an iron bridge reflected the wider spread of factory-produced iron bridges in Michigan, using a Pratt Truss, also called the Murphy-Whipple or Quadrangular truss, a single-intersection design with vertical struts and diagonal ties whose diagonals do not cross the posts. With the coming of the automobile, traffic demanded a two lane bridge, and a reinforced concrete bridge dedicated in 1931 and completed in 1932 served until 2005; it was built under the State Reward Act, with half the cost paid through the State Highway Commission and the balance paid by the village and County Road Commission. The area's river crossing and water landscape were further reshaped after April 18, 1975, when Williamston received 4.89 inches of rain in seven hours, causing the most devastating flood since 1904 and resulting in the loss of the 1840 dam and its mill pond. State officials denied efforts to rebuild the dam because of natural fisheries restoration and other environmental concerns, and in 1998 a boulder impoundment funded by a Natural Resources Trust Fund grant and bonds sold by the Downtown Development Authority raised the water level over one mile while providing whitewater recreation and natural wildlife habitat.