This article examines the way in which an environmental 'problem' comes to be constructed as such. It takes as a case study the issue of sand and gravel aggregate extraction from the Brisbane River, in South-east Queensland, and analyses how this came to be defined as a 'problem' requiring a policy response on the part of key decision-makers, including concrete companies, local and state government agencies, riverside residents and environmental groups. The dispute over whether dredging should be labeled as an environmental problem is analysed using the theory of environmental claims-making, which provides an analytical structure for identifying the three major stages through which environmental problems are constructed, namely: assembling, presenting and contesting claims. In addition, we discuss the process of 'non-decision making' by which certain policy options are ruled out from consideration and political action. Data were collected from interviews with key players in the dredging dispute, and were combined with analysis of relevant documents and newspaper articles. The environmental claims-making analysis illustrates the way that environmental problems are socially constructed and therefore can be fully understood only when placed in their social, cultural and political context.