The Roaring Twenties Drought - 1920 to 1921

The drought of the 1920s was mostly focussed in England and south Wales with severe flow deficits beginning in summer 1921 across southern England for SSI-12). For SSI-3 however, the event started across England (except for NWENW) and Northern Ireland in spring 1921, continuing for a single season in Northern Ireland and North East England, and continuing until winter 1922 in southern England and Wales. The most extreme low flows were experienced over the autumn and winter of 1921, and for SSI-12 in some catchments in Southern England extend well into 1922. In North East England flow deficits were extreme, in cases, with severe low flows experienced throughout 1921. In North West England and North Wales however, this event seems to have made little impression on flows compared to elsewhere, and for SSI-12, catchments in Scotland experienced mostly mild flow deficits throughout the early 1920s. North-western areas again experienced extreme/severe low flows in winter 1923/1924 in Scotland, Northern Ireland, and South West England and South Wales for SSI-3. For all event characteristics, the median rank for the 1921-1923 event was within the top 10 events for SSI-12 and for SSI-3 the median rank was within the top 10 for all event characteristics except mean deficit.

Groundwater levels appear to have been supressed across much of the Chalk with no clear regional patterns to the groundwater drought. Levels started to fall below normal in spring of 1921 due to very weak groundwater recharge in the winter of 1920-21 and continued to fall with the groundwater drought reaching it’s most intense by late autumn early winter 1921. Although this can be considered a single year groundwater drought it was exacerbated in some areas, such as at Chilgrove House, by the delayed onset of recharge in the winter of 1921-22.