Areal FEH99 calculation – Return Period calculation for polygons

As part of our aim of continuing to add complex rainfall analytics into MAP Rain you can now return a FEH99 Return Period for a polygon – this is the Areal FEH99 methodology as set out in the Flood Estimation Handbook.

How to run

  • From the dashboard click on Rainfall Return Period
  • Set the date you are interested in using the top date selector
  • Select the polygon you are interested in
  • Select the “Get Return Period for Item” option under Rainfall Return Period
  • MAP Rain will then calculate the Return Period and display all the coefficients and results in the map results pane along with a graph of the rainfall intensity for 3 days – includes the previous and the next days.