Before the twentieth century, the Conejohela Valley was a marshy floodplain, with extensive wetlands. The Susquehanna River flooded annually in the spring, and there were more damaging floods approximately once per decade. Thick forests surrounded a mixture of small waterfalls, rapids, and marshes. A wide, flat valley formed; the frequently wide river was a substantial barrier to crossing, both for Native Americans and for colonists. The varied terrain created many nurturing biological habitats, but human passage across the valley and river was extremely difficult. The Susquehanna is very wide in this area, as it nears its mouth on the
Chesapeake Bay. This stifled trade across the lower Susquehanna in colonial
Pennsylvania and
Maryland. In 1730, the
Wright's Ferry was established to cross the river. Later the first
Columbia-Wrightsville Bridge was built, once believed to be the longest covered bridges in the world. It was replaced by bridges built of structural steel, large enough to carry a range of vehicles. The modern bridge opened in 1930; it was dedicated in 1980 as the Veterans Memorial Bridge. ==Flooding==