In the context of flood management, this thesis investigates the relationship between spatial rainfall and runoff production, for a range of scales and catchment types. A methodology for the spatial-temporal rainfall simulation of hourly rainfall is developed and the sensitivity of simulated flood runoff to the representation of observed and simulated spatial rainfall is evaluated. The study is based on 15 years of radar data, 21 raingauges and 12 flow stations from the 1400 km2 Lee catchment, UK. Results show a complex picture. The dominant effect is the spatial variability of the rainfall....