Vanport, Oregon 1948
Vanport, on the south shore of the Columbia River across from Vancouver, Washington, was a community built quickly during World War II to provide housing for workers at the Kaiser shipyards in Vancouver and Portland. The 1948 flood lasted 20 days and killed 32 people. Another seven were reported missing and presumed dead. The community of 18,000 was destroyed.
Elsewhere in the Columbia Basin, the flood destroyed 5,000 homes, forced some 50,000 people to evacuate and caused an estimated $100 million in damage.
The U.S. Army Corps of Engineers responded to the devastation by developing a multi-use reservoir storage plan for the Columbia River Basin to reduce the impact of future floods. Later, a 1964 treaty with Canada led to the development of millions of acre-feet of water storage for flood control. This reservoir storage is used to prevent floods in the Columbia River Basin.
Portland, Oregon 1996
In February 1996, heavy rains combined with melting snowpack caused by mild temperatures created the worst flooding in the Northwest in more than 30 years. When floodwaters threatened Portland, Oregon, dam operations reduced their impact and kept the river level lower than it would have been otherwise—one foot to one and a half feet lower. Estimates show that these measures saved the region $3.2 billion in catastrophic flood damage to homes and businesses.
How Dams Control Floods
Or, the water can be stored or diverted for other uses—for generating hydropower, to irrigate farmland or to meet other needs. The flood control provided by dams prevents potential disaster and also turns the event into a future benefit.