Storm Claudia, the third named storm of the 2025/2026 season, threatened 18 hours of continuous rain locally and up to 150mm of rainfall; equivalent to one month’s rainfall in a single day. There was extensive heavy rainfall across England and Wales on 14 November, but the storm began to weaken overnight into Saturday, November 15.

Whilst this level of predicted rain produced an amber alert and the risk of flooding in rivers in South Worcestershire including the River Isbourne, we were gladly spared with the river rising only a minimal amount, and certainly not with its historic characteristic of an extremely fast rise in level.

Whilst it is not possible to accurately explain why this was, a range of factors will have come together and influenced the impact

• Firstly, no two rainfall events are ever the same so trying to compare against previous downpours is difficult. On this occasion we did experience in excess of 100mm of rainfall, itself at the upper end of expectations
• The ground had fortunately been softened by earlier autumn rain which clearly reduced the amount of surface run-off and allowed a huge amount of ground absorption, especially given how dry the summer had been
• The impact of the 170 interventions on the River Isbourne whose purpose is to ‘slow the flow’ and aim to remove the storm surge peaks associated with the Isbourne.

Identifying the significance of any of these factors is incredibly difficult, however the Isbourne Catchment Group has recently embarked upon some further studies with the University of Gloucestershire, who were instrumental in the development of the original hydrological model and natural flood management strategy for the Isbourne.

The studies aim to look at the 10 years of work undertaken by the Isbourne Catchment Group and we hope to be able to quantify as best as possible the impact of the woody dams, scrapings etc which have been implemented as part of the ‘slow the flow’ strategy. Equally, moving forward it is hoped to analyse the long term cost benefit of the work undertaken in reducing flood risk.

Our aim will be to utilise any outputs, when developed to hopefully create an opportunity to further engage with funding bodies by demonstrating the low cost / high impact of the adopted natural flood management strategy, and as a consequence to secure more funding to continue the work on the wider catchment.

We will keep you posted.

Jem Williamson
Chair of Isbourne Catchment Group Jem.williamson@outlook.com