Modelling the impact of spending on defence maintenance on flood losses: summary report

This study explored the relationship between inland flood defence maintenance and flood defence failure due to breaching (caused by structural failure). It also estimated the total benefit derived from river flood wall and embankment defences and the associated upkeep costs of these defences. Flooding in the UK continues to have a devastating impact on society. Severe flooding causes damage to property, infrastructure and agriculture. It can also tragically result in loss of life. Flooding in the last two decades has occurred after more extreme rainfall and has caused more economic damage than has previously been seen. Six of the ten wettest years on record have occurred since 1998 and overall in the UK, the period 2010-2019 has been 5% wetter than 1961-1990. More details on recent flood events are given below, emphasising the ongoing need to maintain flood defences protecting property. 

They key findings from this study are: 

1. River flood defences provide a benefit of £568m per year.
2. Losses due to river flood defence breaching are not sensitive to adjusting the balance between defence maintenance and capital spending.
3. Recent experience has demonstrated that well-funded flood defence systems rarely breach. 
4. For every £1 increase in maintenance spending almost £7 is saved in capital spending.