The ‘intangible’ effects of flooding are now recognised to be significant, and need to be assessed in any MCA. The human health and loss of life effects of flooding are considered here, but the latter not with monetary values.
The effects on human health as a consequence of flooding range from risks to life – hypothermia and injuries during, or immediately after the flood – to more long-term physical and psychological health effects during the weeks or months following a flood.
Identifying whether it is proportionate to include an assessment of the potential for risk to life within an appraisal is related to an understanding of how fatalities from flooding occur.
There are a number of situations and different elements which lead to the potential of fatalities from flooding. Many deaths have not been related to the characteristics of flood itself, but have been caused by behavioural responses or actions of the victims (i.e. driving or walking through flood waters or trying to clear drains in flood conditions). Such fatalities are very difficult to account for when assessing the potential for risk to life from flooding and to include within a project appraisal.
There are circumstances, however, whereby the nature of the flood risk may lead to a higher potential for risk to life (such as fast-onset, high-velocity or very deep floods) or the circumstances of the flood (e.g. with an onset at night or an unexpected flood). These situations have occurred in the past across Europe and, although there have been significant improvements in flood warning and emergency planning, severe flooding might still create the potential for such fatalities in the future. The other situations are when there are high numbers of vulnerable people (e.g. in care homes or schools) or people are located in vulnerable locations (e.g. caravan/camp sites) where there is little shelter.
Appraisal of risk to life should therefore be considered in those situations which are shaded below and include (or are a combination of):
- Where the expected flood has high-velocity or deep flood waters (or a combination of both).
- Where the speed of onset is rapid, permitting little time for warning the public or evacuating areas at risk.
- Where there are large numbers of highly vulnerable people (e.g. elderly or schoolchildren).
- Where people may be vulnerable due to lack of shelter (e.g. caravan/camp sites).