Reduction of soil fertility downstream due to impoundment

Incidence 
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.
Type 
(E) Emanations of other problems