The construction of large reservoirs such as the man-made Brokopondo lake, is certainly not the result of proposals and conclusions of biological studies, but rather of political, technological and economical decisions without serious consideration of the biological implications. The biologist is faced with the results of a serious and hazardous intervention in the environment of man, animals and plants, which must be evaluated and if possible managed after planning and construction. Therefore it is a positive development that in recent years in more cases the ecological aspect of dam construction is integrated in the plans. In the case of Lake Brokopondo, officially called Prof. Dr. Ir. W. J. van Blommesteinmeer, long before the work was started the biological implication of the construction of a dam in the Suriname River was considered in a scientific study (SCHULZ 1954) sponsored by the Foundation for Scientific Research in Surinam and the Netherlands Antilles (STUDIEKRING), which study however, appeared to have no influence on the planning. The “barrage” was built by the Suriname Aluminium Company (SURALCO) for hydro-electric purposes and completed on February 1, 1964. In 1962 the Executive Board of the Netherlands Foundation for the Advancement of Research in Surinam and the Netherlands Antilles (WOSUNA) allocated funds for the carrying out of the Brokopondo Research Project and so in November 1963 the hydrobiological investigations in the future lake region could be started. Some months later also botanical and ichthyological research began.