WHS spreadsheet to apply the non-flood years adjustment procedure within the FEH statistical methodology. The methods are those described within FEH Volume 3, previously known as ‘Permeable Adjustment’. Within the report ‘Review of flood frequency estimation in groundwater dominated catchments’ (EA, 2022) it was noted that catchments with a high proportion of non-flood years tend to be those which have a low rainfall (SAAR) and are not restricted to permeable catchments. The WHS Non-Flood Years Adjustment spreadsheet will allow adjustments for all catchments that have non-flood years and is compatible with outputs from WINFAP 5, being able to utilise both observed and deurbanised L-moments.

Please note that it is important that the Excel ‘Calculation Options’ are updated to optimise the performance of the fitting algorithm as recommended in the online guidance.

The WHS Non-Flood Years Adjustment Spreadsheet is available to download here. This spreadsheet is an unsupported beta version.