Autumn Flooding of Property Strikes Again


The recent autumnal affects of flooding on property have been all over the media, this year centred on parts of mid Cornwall.  The Rivers Fowey, Par and the St Austell river burst its banks and could not cope with the sudden influx of water when over 2 inches of precipitation fell in a matter of a few hours.

This was almost exactly a year after the tragic flooding in and near Cockermouth in Cumbria. Is this becoming an annual event?

Early autumnal flooding in recent years has included Boscastle in Cornwall, as well as flooding in Yorkshire, the Severn and a number of other areas of the country.

The majority of this kind of flooding is along the west side of the United Kingdom which receives the most rain, although localised intense periods of rainfall can happen almost anywhere in our climate.

Localised very heavy downpours, where several inches of rain fall in the space of a few hours, are usually to blame.

The reasons for the flooding usually include a combination of factors, some which are beyond our control and other factors that we can influence.

We have little practical control over the following factors:

The intensity and amount of rainfall that falls in a location.  Such factors are considered “Acts of God”.

The level of rain preceding the heavy rainfall will, along with the geological make up of the ground, determine the extent that the water table is saturated and whether there is any capacity in the ground to absorb some of the rainfall or slow its release into the rivers and streams.

Factors that we can influence include:

Blocked drainage channels, which are compounded by leaves and other autumn debris. Local authorities need to keep these clear, although with the pressures on budgets, the frequency with which these are maintained may suffer.

The increase in deforestation and urbanisation and the concreting of various areas leads to quicker flow and surface water run off into the rivers and streams.

Illogical planners who still insist that they should build on and / or  release land for building on flood plains.

Older style bridges with traditional arches are river pinch points which, with trees and other debris, can become dams and compound the flooding and lead to bridge collapse (e.g. Boscastle).  This style of construction with heavy arches should not be built any more, whilst the historic bridges, such as the bridge lost at Cockermouth and that in danger at Lostwithiel, are sometimes a legacy from the medieval period. Maintenance of this style of bridge is very important. This includes the channels under the arches, which is important to maximise efficiency of waterflow. Sometimes features can be added upstream to prevent trees and other debris getting washed downstream which would allow the arches to become the framework for a dam (as happened at Boscastle).

Medieval Bridge at Lostwithiel, Cornwall
Medieval Bridge at Lostwithiel, Cornwall
~ in more tranquil times.

Lack of investment in new flood defences is also likely to continue under the austerity measures now in place.

We also have to consider the changes in the levels of rainfall.  The Met Office confirms that these levels have not changed as much as we might think.  Certainly our perception has changed, but how much of that is due to personal circumstance, and how much is due to the incessant news coverage with television being piped into our houses, cars, phones and computers, almost streamed 24/7, it is impossible to say.

Around the world, floods have often caused complete devastation such as recently in Pakistan and Bangladesh.  Here in the UK, the 1953 East Coast Floods with a North Sea tidal surge killed 2,400 people on both sides of the North Sea reminding us how powerful the forces of nature can be in our own protected corner of the world.  The Lynton and Lynmouth Flood Disaster of 1952 also captured many headlines of the day where some 32 people died.

Whilst there are some factors listed above which can help a community with a community approach, what can an individual do?

When people are looking at buying a property, they should check whether the building is located in or near a flood plain. Important information can be read online on the Environment Agency’s website, including examining the Risk of Flooding Map.  If you have already bought a property that may be at risk of flooding, you will find useful links to help in the event of a flood, and how to register for the Floodline alert on the Environment Agency’s website.

Also, you should check that there are no restrictions on your Buildings & Contents Insurance.

These links are also to be found on our Useful Links page .

23 November 2010