Beach nourishment is a common coastal management strategy used to combat erosion along sandy coastlines. It involves building out a beach with sand dredged from another location. This paper develops a positive model of beach nourishment and generates testable hypotheses about how the frequency of nourishment responds to property values, project costs, erosion rates, and discounting. By treating the decision to nourish as a dynamic capital accumulation problem, the model produces new insights about coupled economic geomorphological systems. In particular, determining whether the frequency of nourishment increases in response to physical and economic forces depends on whether the decay rate of nourishment sand exceeds the discount rate. © 2009 Elsevier Inc. All rights reserved.