sentences:  This has resulted in eutrophication of the river water and has facilitated the spread of diseases of poor hygiene such as cholera, typhus and dysentery.The construction of two major dams regulating the flow of the river has had a major effect on wildlife and human populations in the lower Zambezi region.When the Cahora Bassa Dam was completed in 1973, its managers allowed it to fill in a single flood season, going against recommendations to fill over at least two years.