How to produce our own flood risk assesment? Are there any examples or templates available?

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Hi there,

We are going through the planning process to convert our dairy into an annexe but have been told by Snowdonia National Park Authority that we need a flood risk assesment. We are next to a tiny river but it has never flooded anywhere near the dairy.

This is what they have said,

I attach a screenshot of the correct Development Advice Map outline, which shows
the development site is in fact within the C2 outline. You will therefore need to
submit an FCA. For a development of this scale, we would not expect any hydraulic
modelling to be undertaken. The FCA is likely to be something you could undertake
yourself. The purpose of the FCA is to seek to ensure the development is as safe
from flooding as it can be by incorporating appropriate mitigation measures and flood
resistant/resilient materials and techniques into the design where possible (e.g.
raised floor levels, tiled or concrete floors rather than wooden, raised electrical
sockets, non-return valves on water inlet and outlet pipes, etc). Any residual risks
should be shown to be manageable.

Does anybody have an example of the kind of thing we need to produce or know of some kind of template? We've been quoted thousands of pounds to get it done for us and simply dont have that kind of money.

Any help with this would be amazing! Thanks, Catrin.
 
I would just take a look on Gwynedd council's Planning website, for recent, similar applications nearby. I'd look myself, but I know exactly one word of Welsh - well, two now I come to think of it.
 
Aha! Great idea, I'll take a look. Many thanks, diolch yn fawr!
 
Google "Improving the Flood Resilience of new Buildings" by DCLG. It's a big read but contains practical suggestions on
improving resilience - such as horizontal laying of plasterboards on walls; running socket cables down from the floor above; solid floor with hard finish, with tanking; wall cavity not extending below g.l. etc.
It's all basic stuff and is easy to do yourself in an evening; no more than an A4 sheet and some notes on your plans should suffice. It's certainly not worth giving someone thousands of pounds to prepare.
 
Google "Improving the Flood Resilience of new Buildings" by DCLG. It's a big read but contains practical suggestions on
improving resilience - such as horizontal laying of plasterboards on walls; running socket cables down from the floor above; solid floor with hard finish, with tanking; wall cavity not extending below g.l. etc.
It's all basic stuff and is easy to do yourself in an evening; no more than an A4 sheet and some notes on your plans should suffice. It's certainly not worth giving someone thousands of pounds to prepare.
But that's not really the crux of a flood risk assessment, which is to determine the likelihood of a flood affecting the development, it will then set out recommendations to mitigate any damage to the property, if appropriate, of which that aspect you have highlighted. I'm not really sure how a layman can do a FRA themselves.
 
But that's not really the crux of a flood risk assessment, which is to determine the likelihood of a flood affecting the development, it will then set out recommendations to mitigate any damage to the property, if appropriate, of which that aspect you have highlighted. I'm not really sure how a layman can do a FRA themselves.
TBH, you may be right but I did one on these lines recently and it was accepted without any questioning. I think it's just a case of them wanting us to jump through a few hoops.
 
How the F can you write a flood risk assessment if you have not got a clue how to assess flood risks?

It's not just a paper exercise that the planners file away either. It gets checked.
 
A Flood Risk Assement can be invalidated by housing and / or commercial developments built after the Assesment was conducted. Drainage on the new development will alter the rate at which rain water reaches the stream / river and increase the risk of flash floods.

We bought a plot of land next to a babbling brook in 1979. The flood risk quoted ( which we did not check ) was once in 100 years.
composite 1981 1992.jpg



These only lasted a few hours before the stream dropped back down. Fortunately the house was not affected.
And two less invasive floods as well. The wall was built to prevent further erosion of the bank when the stream was swollen by rain.
 
I have to do them from time to time, but only in Flood Zone 2 (England) so I don't know how that equates to the Welsh planning system. If it was Zone 3 I would get a specialist report.

Certainly in England there is lots of guidance available on how to write the risk assessment and is really quite straightforward. The important thing is to assess the actual risk of a flooding event, luckily mine have always been extremely unlikely as the flood zone has only covered a small part of the low lying surrounding land, not the buildings.

However you are still supposed to consider the risk and include some flood resilient design but it is just standard construction such as concrete foundations to a certain depth, dense concrete block cavity walls below DPC etc.
 
I have to do them from time to time, but only in Flood Zone 2 (England) so I don't know how that equates to the Welsh planning system. If it was Zone 3 I would get a specialist report.

Certainly in England there is lots of guidance available on how to write the risk assessment and is really quite straightforward. The important thing is to assess the actual risk of a flooding event, luckily mine have always been extremely unlikely as the flood zone has only covered a small part of the low lying surrounding land, not the buildings.

However you are still supposed to consider the risk and include some flood resilient design but it is just standard construction such as concrete foundations to a certain depth, dense concrete block cavity walls below DPC etc.
Well it appears that wessex is the Flood Risk Meister and is presumably about to inundate us with all the available guidance on how to write ones own FRA ......
 
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