An extensive study of a large catchment in north-west England reveals the nature of changes in the fluvial geomorphology and hydrology over the period of record. The causes of change are investigated through examination of climate and land use practices. Novel methods of time series analysis are used to explore long-term trends. Recommendations are made for management options that take account of future uncertainty and indeterminacy. The findings of this study provide a basis for a strategic plan for more sustainable use of the River Lune catchment. Increased frequency of intermediate magnitude floods (since 1950) is largely the result of land drainage and local climatic variability (after 1970). Over the last 30 years, a greater proportion of annual rainfall has fallen in winter, with a concurrent increase in wet day frequency. More runoff from upland areas, observed over the last 25 years, is the result of both increased rainfall intensity and heavy grazing. Increased upland runoff and loss of lowland water storage have serious implications for water resources. Total annual runoff has declined partly because of reduced natural water storage within the catchment.