User:Cdmhume/sandbox

The Columbia River has the greatest annual drainage as compared to all other rivers along the Pacific coast . Before the introduction of dams on the river, the changes in water level rose and fell predictably with the seasons and a nine meter displacement existed between the spring snowmelt highs and fall lows . After the dams were built, however, the river changed unpredictably and in some areas the previous maximum and minimum water levels were altered by several tens of meters . No longer linked to the seasons, water conditions became subject to United States power demands . After the damming, the water during high floods began to cover much of the valley’s arable land - carrying with it fertile soil when the water retreated and leaving agricultural land useless

From 1965 to 1969, 27, 312 acres were logged along the Columbia River to remove timber from the new flood plain . The slashing of vegetation along the shoreline weakened soil stability and made the land susceptible to wind erosion, creating sandstorms. Conversely, in wet periods, the cleared areas turned into vast mud flats .