given by 36.6mm divided by 6 hours, which is 6.1mm/hour. Storm profiles The above method is sufficient for finding the overall depth of rainfall during a storm. However, it is often useful from an engineering perspective to predict the intensity of rainfall during the storm, to allow structures such as drains and sewers to be designed with sufficient capacity for stormwater. In general, the intensity of a storm is highest at the mid-duration point (known as the peak), and lowest at the start and end of the storm. Therefore, peaked profiles are applied to the storm data to provide a more realistic description of the rainfall intensity during the storm. Flood Estimation Handbook The Flood Estimation Handbook was published in 1999 and replaces the FSR. It is based on the percentage runoff equation: where PR is percentage runoff, PIMP is percentage imperviousness of the catchment, SOIL is the soil index and UCWI is urban catchment wetness index. References Hydrology Environmental engineering Technical books Water in the United Kingdom