Extensive study or the rivers Niger and Benué in order to describe the hydraulics and morphology with the aim to improve inland navigation in Nigeria. Part I gives a summary of the original NEDECO studies and their results as contained in the Report, without summarising the information obtained from other sources. This is followed by a description of the actual investigation, its staff, the planning, the instruments that were used, etc. (Part II). Part III deals with the Rivers, explaining their hydrological and morphological regime and describing the other characteristics. Part IV provides information on transport, navigation and navigability, whilst Part V summarises the defects of the shipping conditions. Finally, Part V I gives a discussion of the various possibilities for improving the navigability, resulting in a recommended programme of improvements. A glossary of technical expressions and a list of symbols and units have been included in the Report. General maps of West Africa and of Nigeria are inserted inside the back cover of this Report.