This study describes an environmental impact assessment conducted in conjunction with the Apure River Improvement Project in Venezuela. The study area consists of two very large sub-areas: a 20,000-km(2) area that is being studied with the objective of flood mitigation, and an area along 930 km of rivers that is being studied for navigation purposes. The study area is a vast and almost virgin region, barely reclaimed and sparsely inhabited, where the traffic is rare and environmental information is difficult to obtain. The total study period was restricted to 21 months, which was too short for a comprehensive environmental study, even one limited to reviewing available literature and cursory surveys in the field. We proposed an informal one-day workshop in an attempt to explore more efficient methods of collecting environmental information. The workshop was held as the first part of an infrastructure planning study by the Japan International Cooperation Agency.