River Nile used to deposit 100 million tons of sediment a year on nearly one million hectares of land in the Nile Valley. After the building of the Aswan Dam, the Nile deposits only a few tons of sediment per year, most of that comes as a result of riverbed erosion, meaning the gradual loss of riverbed soils. To compensate the silt trapped behind the dam, Egypt must apply artificial fertilizers on an ever increasing scale.