Category Archives: Flood Risk Assessment

Flood Defences for Bradford on Tone

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Where is Bradford on Tone?

Bradford on Tone is a small settlement on the River Tone. It is situated to the west of Taunton, and has a population of 622.

Where are the Flood Defences?

The below map shows the location of the flood defences (mapping under PMCL No. LAN1001865) :

flood defences bradford on tone

Are the Flood Defences Effective?

To a point. But they are not very good.

The defences are recorded as being in fai to good condition. The southern embankment has a crest level of 31.68mAOD, and this would be overtopped given a 1:20 year flood event. It provide protection against a 1:10 year event just.

These scenarios do not account for climate change that will increase flow volumes in this river by 4.7%.

A 1:100 year event is perhaps more appropriate level of defence, and cities such as London will for the most part have 1:1000 year protection.

1:10 Year Explanation

This last section made with gemini AI

A 1:10 flood event, also known as a 10-year flood, is a flood event that has a 1 in 10 chance (10% probability) of occurring in any given year. It’s important to understand that this does not mean the flood will occur exactly once every 10 years, nor does it guarantee that it won’t happen more frequently.  

Here’s what you need to know about 1:10 flood events:

  • Probability: A 1:10 flood has a 10% chance of occurring in any single year. This means that even if a 1:10 flood happened this year, there’s still a 10% chance it could happen again next year.  
  • Recurrence Interval: The “10-year” part refers to the average recurrence interval, which is the average time between events of a similar magnitude. However, this is just an average, and floods can occur more or less frequently due to natural variations in weather patterns.  
  • Flood Risk: 1:10 floods are considered relatively frequent events. They can cause significant damage to property and infrastructure, and pose a risk to people’s safety. 

Incorrect Flood Zone 3b on Flood Mapping

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Incorrect Flood Zone 3b on Flood Mapping

This is about as niche as it gets . . . . but here we go!

We have recently seen a couple of examples where Cornwall Council’s flood mapping (which is different to flood map for planning) gives some very strange results for Flood Zone 3b.

How Flood Zones Normally Appear

Perhaps the most familiar flood mapping for those “in the trade” is the flood map for planning. Typically we see the darker blue (more often flooding)  Flood Zone 3, fringed with lighter blue (less often flooding) Flood Zone 2.

screen shot from flood map for planning

Screen shot from flood map for planning.

In flood mapping it is always the cases that a “more often” flood outline (shaded area) never go outside of the “less often” flood outline. Look:

Flood Zones from Some Older Mapping

In the above slide the dark blue areas do not extend beyond the light blue areas. They can extend up to the edge, but not beyond.

Flood Zone 3b on Cornwall Council Flood Mapping

So when we first saw the mapping from Cornwall Councils’ own mapping service below we knew something was wrong with it. Apart from the strange colour scheme, you can see Flood Zone 3b Extends well beyond Flood Zones 2 and Flood Zone 3a.

So there is something wrong with the modelling of Flood Zone 3b at this site.

Incorrect Flood Zone 3b – Cornwall Mapping

The image below shows the beginning of our investigations in to the error. We made a detailed study of elevations in the vicinity for starters and then wrote a report to explain why the site in this instance should not be included in Flood Zone 3b.

Detailed Contour Zones on Google Satellite Images

And we are happy to say that the argument we politely put forward worked well, and the permissions was granted.

If you have issues with a site that appears to be included in FLood Zone 3b, when maybe you think it shouldn’t be then please do contact us and we will be glad to help. We can deal with this issue as part of a flood risk assessment or as a bolt on.

We have seen strange behaviour like this in Cornwall Council’s flood mapping, and also in Bristol City Council’s Flood Mapping.

 

60 Day Rule for Camping & Flood Risk

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60 Day Rule for Camping & Flood Risk

You have been Asked for a Flood Risk Assessment and Flood Warning Plan when you have decided to extend your 28 days camping rule, to 60 days you may be required to submit a Flood Risk Assessment and a Flood Warning Plan. We can write both of these for you.

In the last chapter on this page we offer a up a few tips if you would like to try and write you own flood risk assessment.

a picuture show camping and tents flooded in a field the water is muddy and you cannot see the gound the tops of the colourful tents are poking out of the surface of the flood water

Glastonbury 2005 – Creative Commons 2.0 – sebFlyte

The 60-day Rule

  • Introduced in July 2023, it allows landowners to use their land as a campsite for up to 60 days per calendar year for up to 50 pitches, without needing full planning permission.
  • It applies to tents, motorhomes, and campervans (but not touring caravans).
  • You must notify your local planning authority beforehand with details like dates, site plan, and waste disposal methods.

Flood Risk and the 60-day Rule

Sites in Flood Zone 2 or 3 Require Additional Consideration

Even outside Flood Zones 2 & 3, be Cautious

      • Check historical flood maps and local flood risk information.
      • Choose campsites on high ground, away from bodies of water, and avoid low-lying areas.
      • Stay updated on weather forecasts and be prepared to evacuate if necessary.

Remember:

  • The 60-day rule simplifies permissions, but flood safety remains paramount.
  • Prioritize safety and choose campsites with minimal flood risk, regardless of the rule’s applicability.

A Little Help

We fully appreciate that some smaller campsite, may not make a huge amount of money, and as such we provide the below hints for writing your own Flood Risk Assessment which perfectly OK thing to do.

  • Why not use Google Gemini to Write the Bulk of the Text for You
  • Order a “Product 4” from the Environment Agency (You can do this via “Flood Map for Planning “)
  • Use the data they provide (you have to wait 20 days) to write you report.
  • Move camping areas to low risk areas.
  • Use flood risk areas for open areas or sports areas.
  • Describe what people will do if the campsite becomes flooded, and where they can shelter.
  • Read about “flash flooding” and what the dangers are, think about how you can warn people about it (sign up to flood warnings and sever weather warnings).

Lots of Help

We can do this for you if you like.

Southwest Environmental Limited: Your One-Stop Shop for Flood Risk Assessments

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Flood Risk Professionals

Flooding is a natural disaster that can cause significant damage to your property. It can also lead to business interruption and loss of income. That’s why it’s important to have a flood risk assessment in place to protect yourself from the financial and emotional costs of flooding.

a man is cycling along a flooded street in england, the water is brown and about 10cm deep, he is not looking hwere he is going and behind him there is a row of shop one is painted yellow with the words cartridge world written on the sign, the buildings in the background look quite old maybe 100 years old of more

Image: johnda CC BY-SA 2.0

Southwest Environmental Limited is a leading provider of flood risk assessments in Somerset. We have a team of experienced professionals who can help you assess your flood risk and develop a plan to mitigate it. We offer a range of services, including:

  • Flood hazard mapping: We can use our advanced mapping technology to identify areas that are at risk of flooding.
  • Flood risk assessment: We will assess your property’s vulnerability to flooding and identify potential risks.
  • Flood mitigation planning: We will develop a plan to reduce your flood risk, such as installing flood barriers or making changes to your property’s drainage system.

Why Choose Southwest Environmental Limited?

  • We are experienced: We have been providing flood risk assessments for over 15 years.
  • We are qualified: Our team of professionals is qualified to assess flood risk.
  • We are affordable: We offer competitive rates for our services.

Contact us today to schedule a flood risk assessment.

Don’t wait until it’s too late. Protect your property from flood damage with a flood risk assessment from Southwest Environmental Limited.

Flood Risk Assessment – Newmarket

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Writing a flood risk assessment if carefully done is a largely scientific process. By “scientific” we are alluding to the fact that the content is grounded in fact, or at least as far as the available data is accurate.

If a flood of a certain depth is “forecasted” when viewing available flood data for the site then we can raise the building up. Facts and reactions to those facts. This is what we like.

One part of the Flood Risk Assessment is the Sequential Test. This “non-scientific” part of the Flood Risk Assessment we could do without. It is a policy based, almost artistic endeavor that relies on the matching of unqualified of opinions, sometimes resulting in mismatches.

Image: johndal CC BY-SA 2.0

The sequential test relies on the following ingredients in order to work:

  • search area
  • search criteria

Both of these ingredients are open to debate in terms of their size and type respectively, and as such we have to be careful to follow established guides that have been issued by some of the more proactive administrative authorities’ so that we can demonstrate plausibility.

If you would like to discuss a Flood Risk Assessment for a Project, or a Sequential Test, then please do get in touch.

Flood Risk Assessment – Bristol

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Flood Risk Assessment – Bristol 

Southwest Environmental Limited have recently been commissioned to prepare a flood risk assessment for a site in Bristol (Avonmouth). The site is subject to tidal flooding and, as if typical with the majority of the Avonmouth area, is low lying.

Avonmouth – Docks

Key factor explored in the flood risk assessment will be the anticipated flood depths from tidal, fluvial and pluvial (rain) flooding, and then design of mitigate measures.

In this instance the application is retrospective which will create further challenges. We will have to make sue of the current site lay out, existing outbuildings and other factor in order to present a positive proposal.

The report will include a Exception Test and Sequential Test. 

Image rights

Description
English: The Royal Edward Dock at Avonmouth, 13 March 2014.
Date
Source Own work
Author N. Johannes

Flood Risk Assessment – Battersea – London

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 Flood Risk Assessment – Battersea – London

Acting on Instruction from an Architect Southwest Environmental Limited have begun preparation of a flood risk assessment in Battersea, London.

The proposed development is for a property refurbishment with a basement extension. The flood risk assessment will look at fluvial, tidal and surface water flooding risks.

We will also make an appraisal of flood defences in the area. Most of the flood defences along the Thames are being upgraded to account for climate change, and as such provide a 1:1000 year protection levels provided they are no breached.

The proposed development does not include sleeping of primary living accommodation at basement level, this is advisable as the Environment Agency will Ilkley object to sleeping accommodation in basements, when in Flood Zones 2 or 3.

Flood Risk Assessment – Devon

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 Flood Risk Assessment – Devon

Southwest Environmental Limited have been commissioned to undertake a Flood Risk Assessment for two lake side holiday lodges, in Devon.

We were approached by Architects who provided plans and fave a description of the proposed development for 2 holiday lodges situate don the edge of a Lake.

This type of development is becoming very popular as it is the 3rd FRA we have prepared for such a development in the Southwest, in recent months.

A Pond

Perhaps the single most important factor is the likely flood depth. For this we have two sources, one being slightly quicker than the other which was used in this instance because the report was required on a quick turnaround.

Southwest Environmental Limited have prepared Flood Risk Assessments for a large variety of developments from small houses, to factories and 200 home developments, we provide the same high level of services to all clients regardless of project value. 

Flood Risk Assessment – Devon

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Flood Risk Assessment – Devon

SWEL have recently completed a Flood Risk Assessment for a Site in Totnes, Devon. Our total turn around time for the production of the report was 7 workings days.

Detailed Flood Depth Data

Usual RoFRS Data but on High Resolution

The report includes in depth flood depth data, which was sourced on a quick turnaround.

The report include surface water details (brief), design details and sequential test. The site use type is not ordinary and we made a best case argument for vulnerability classification in this instance.

SWEL regularly prepare flood risk assessment for sites of all types across the UK. We aim to deliver a quick successful report which include a breadth of information suitable for the job in hand.

If you require a Flood Risk Assessment please Contact Us.

Flood Risk Assessment – Bristol

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Flood Risk Assessment – Bristol

SWEL were recently commissioned to undertake a flood risk assessment in Bristol. This site is an interesting one in terms of settings. As is resides within some characterful gardens walls, which have a curved to match the site boundary.

A Pub near the Site

The key as always with a good flood risk assessment is collecting a wide selection of data to characterize flood risk at the site. 3rd party data reveled flooding of significant depth on site, whilst the Environment Agency data from neighboring sites showed details that will aid in the design of the building.

The report also includes exceptions test, sequential test and surface water recommendations.