Evaporation basins are attractive engineering solutions to the problem of the disposal of groundwater and saline drainage from irrigated areas. Typically, environmental impact assessments are restricted to estimates of biological or conservation losses, for example of populations, species or habitats. Generally they fail to anticipate what biological characteristics are likely to develop and what social effects these could have. As these characteristics can sometimes require active and continuing management they may contribute, perhaps significantly, to the operating costs. The Wakool-Tullakool Evaporation Basins, in southern New South Wales, Australia, are used to illustrate these points. In the ten years since construction began, these basins have acquired a rich aquatic plant flora and become a wetland of local, regional and, arguably, international significance for waterbirds and waders. In addition to these positive characteristics, the basins have also developed some negative ones, including economic losses to the rice industry caused by a few waterbird species.