Floodplains and flood defences

The concept of maintaining areas and entire ecosystems where water traditionally has flooded is critical, both to protect the natural habit and provide the natural attenuation from rivers to protect people's homes and businesses. It was a well understood concept and for thousands of years, flood plain land has been protected.

Many civilisations around the world have evolved around such flooding, with the Nile in Egypt an excellent example. Such flooding was celebrated due to the renewed fertility of the land.

During the last 10 years however, there has been significant erosion of the actual basis of what a floodplain is in the UK, largely as a result of the Environment Agency changing the basic terminology, without industry wide agreement.

Flood plains, flood defences and flood mitigation

Traditionally, the floodplain was land which, as per PPS25 and the Government National Planning Policy meant "land which must flood in the natural operation of a river of main watercourse". It is absolutely critical that such land is and remains protected. The public would expect, if not demand, for such land to remain protected for the benefit of everyone. Such agricultural land can often benefit from such flooding as the rivers organically rich silts.

The primary problem is that EA has applied a completely different criterial to floodplain terminology, which few independent hydrological experts accept. The EA currently ignores the Government Policy and states it is land which floods in a 1:25 year event. All independent research has shown that the public do not accept, that an event which could barely happen three times in their life is anything like regular. Regular, is when something occurs essentially every year as a natural operation.

 

That is not saying that the risk is not considerable and action is necessary to understand (by obtaining a flood risk assessment) and mitigate the flood risk, so far as possible.

The EA fails to understand that it is not the risk, but the consequences of flooding which concern the public. Pure hydraulic modelling may show a section of land flooding, but with (for example a building set off the ground and adequate warning) the occupants would experience no damage. Where as many householders who are located on land with a lower hydraulic risk (based on the EA maps) but are not protected in any way. Such failures can cause damage to fabric and fittings which can take over 6 months to fix and enormous disruption for families or businesses.

Many communities around the UK are based around Rivers and the effect of the EA failure to follow the Government Policy is that it blights communities and especially individual residents and small businesses. Applications are often agreed for major housing developers (with expensive lawyers) or when Local Authorities give themselves permission for their own projects. The system is not fair. There is not one sensible rule applied evenly.

The Environment Agency are tasked with flood prevention, yet most major flooding events are a direct consequence of their failure to manage and protect communities. Channels are not maintainted adequately like they used to be. Too often the weather itself, developers or the public themselves are blamed.

 

close
YouTube IconTwitter IconVisit Our LinkedIn Civil Engineering Profile Visit Our LinkedIn Civil Engineering Profile