The Geological Survey of Ireland (GSI) has been advised by Met Eireann - Ireland's National Meteorological Service - that international best practice supports the use of longer reference periods to most accurately capture long-term climate variability. A minimum length of 20 years is generally recommended - for example, the upcoming report of the Intergovernmental Panel on Climate Change will use the period 1995 - 2014 and the World Meteorological Organisations recommends 30 years.
Reference periods of 1980 - 2000 or 1980 - 2020 are commonly used both internationally and in Ireland. However, for the purposes of the GSI flood maps, with advice from Met Eireann and working with the Office of Public Works, these periods are extended forwards and backwards to capture a broader range of weather events which have impacted turloughs. As such, the reference period includes flooding that occurred within the last decade up to and including late 2019. I therefore have no plans to change the reference period.