Fluvial processes have always been prominent in theories of landscape evolution, from Herodotus’s (c. 484-420 BCE) observations on the accumulation of silt in the Nile delta, to the nineteenth-century theories of Lyell, and later Davis, which posited the slow action of geomorphic processes such as rivers on the shape of the earth. While Britain has no watercourse on the scale of the Nile due to its small landmass and island status, the quantity of rainfall ensures that rivers and streams are a significant part of the landscape, providing a source of power for industry and the rural economy, and a site for leisure activities. Rivers have also long provided a source of inspiration for British poets, from Michael Drayton’s Poly-olbion to Ted Hughes’s River (1983). More recently there has been an increased interest in fluvial forms and their effluvia in British poetry. In the past ten years three T. S. Eliot prize-winning collections, Phillip Gross’s The Water Table (2009), Sean O’Brien’s The Drowned Book (2007) and Alice Oswald’s Dart (2002), have explored particular river systems and their landscapes – the Severn, the Tyne and the Humber, and the East and West Dart. The Dart River and the Severn Estuary are the focus of two of Oswald's book-length sequences: in both the river systems act upon the landscape and its inhabitants, and in the case of the Severn the tidal river is in turn subject to an extra-terrestrial geomorphic process, the gravitational force of the moon. If the flow and tidal rhythm of rivers provide a visible diurnal example of shifting landscapes, the changes that shape their underlying bedrock are less tangible to human perception. These deep slow processes of interaction between water and rock are fundamental to Oswald’s poetic excavations, as they are in the evolution of the material landscapes that she evokes.