Study of Artificial Flood Generation for Ecological Stream Flow Recovery Downstream of Irapé Dam, Brazil

The restoration of stream flow variability in rivers regulated by dams is a key element to preservation of fish populations. Several species of tropical fish rely on periodical connection of the river with the floodplain during the wet season, which has been severely reduced in heavily impounded and regulated rivers. In order to recover part of the stream natural variability and allow the floodplain connection with the main river channel, reservoirs may be re-operated for artificial flooding. This paper presents the study of artificial flooding downstream of the Irapé Dam, in Brazil. Several peak flows were tested and the resulting floods were evaluated based on steady state river hydraulics. Results allow the location of the flooding areas downstream, which is important to identification of environmental protection areas, as well as the corresponding peak flows. The latter is critical to help identify artificial flood operations with reduced cost and impact to reservoir operation, especially when other competing uses, such as energy generation and water supply, are involved.