ABSTRACT
A complex set of environmental factors, including resettlement of people, health hazards, sedimentation, climatic changes, seismic effects, and archeological losses are involved in river basin development. These factors must be evaluated as an integrated total before a satisfactory project can be developed. Resettlement of people has been one of the most frustrating and tenacious of all the man-made impoundment difficulties. With the building of a dam, and the resettlement of people, large groups of people are forced together in heavy concentrations. Schistosomiasis and fascioliasis are the two snail-borne infections which might be expected in water development schemes; of the two, schistosomiasis is the greater problem. As a mosquito-borne infection, malaria has caused a great deal of problems for development projects of all kinds, going from the Panama Canal to the Kariba Dam. There are three main methods of aquatic weed control: mechanical, chemical, and biological. Ecologically speaking, biological methods are the most desirable and chemical methods the least desirable.
