A number of the rainfall parameters used by the software can be obtained by clicking on the required location.
First select the rainfall model and region tab required; the maps are split between England, Wales & Scotland and Ireland.
Next click on the small map to get to the general area of interest and finally click on the large map to return the values required. The map includes thousands of data points and the values can be loaded by clicking anywhere, not just on the marked towns.
To cancel the map operation simply click the close window button at the top right of the window.
The information has been based on data that is available on the large-scale FSR (1975) maps. Some of this data has also been included on the Wallingford procedure (1981) maps. The maps provided with the software are far more detailed than the A4 maps usually recommended for use with the Modified Rational method. However if greater accuracy is required the engineer should verify these variables by consulting either the FSR or Wallingford procedure maps. We have used triangulation methods to generate the digitised information (approximately 10 million points) but as this data was not originally produced in digitised form the accuracy is not better than manual interpolation.
M5-60, Ratio r, SAAR and Soil data has been sourced from The Met Office and is Crown Copyright.
Note : AAR data for Great Britain is taken from the 1941-1970 AAR map. Data for Ireland is taken from the 1931-1960 map.