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Desktop Study – Slough

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Desktop Study – Slough

Acting on instruction from a client in Ealing Southwest Environmental Limited have prepared a desktop study fro site in Slough.

The desktop study has been made of the site and this revealed that historically the site was of primarily back garden use. But more recently had been used for other purposes.

As is normally the case SWEL order a comprehensive data set, so as to make a review of the site.

It was established that a Phase 2 Investigation is required, owing to current on site use, which is mixed between storage and vehicle repairs etc. 

The report was turned around in 5 days.

Drainage Report – Cullompton

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Drainage Report – Cullompton

Some areas of Cullompton are designated as a critical drainage area. You may have a planning condition which states that:

“As the application site falls within the Cullompton Critical Drainage Area, please submit a Flood risk Assessment”



A flood risk assessment typical is focused on flood risk to the site, when what is required in a Critical Drainage is a Surface Water Drainage Strategy.

The way to deal with most domestic / residential drainage requirement is permeable paves, with added features. Mots consider this an expensive option, but this is due to lack of understanding.

In order to capture run off you must provide a volume of “holding” (an attenuation volume) this usually provided my the spaces between gravels in a soak-away trench.

But why not use these same gravel as a sub-base for permeable paving? You will have to import fill for driveways anyhow. You end up using the aggregate twice for soak-away and for sub-base.

Water from roofs can be fed in to the sub base, and drive water just soaks straight in, avoid the requirement for gullies etc. There are no blockages from leaves.

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.

BRE 365 Soak-Away Tests – Gloucestershire

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BRE 365 Soak-Away Tests – Gloucestershire

SWEL were engaged to undertake BRE 365 soak-away testing at a site in Gloucestershire. The works includes site works and a full written report with design calculations and soak-away sizing calculations according to BRE 365. We include trial pit logs, photographs and extra information we feel may be of use, such as empirical strength estimates.

The site was fairly large and very hilly. Which would have made access rather difficult if it were not for pre-existing access tracks, and a disused railway line which serves as a spine road for our investigations!

There were various fallen trees etc. which had to be removed before we could start work, but our site staff normal carry a selection of cutting tools so as to get things moving as quickly as possible.

Access was Tight ion the Wooded Areas – Note Quarry Face to Rear

In the course of a very long day we managed to complete 7 trail holes, with BRE 365 soak-away testing carried out in each one.

Bedrock was quite shallow at some points across the site. The western extents of the site included a quarry and a disused railway tunnel.

Many of the Soak-Away Pits Reveled Large Limestone Cobbles.

Infiltration rates across the site were variable, reflecting the steep topography and disturbed nature of the ground. The valley bottom showed slower soak-age rates whilst the the infilled quarry showed very rapid soak-age rates, likely due to the use of a very course fill media.

The field work element of each test took between 30 mins and 2 hours, which many of the longer tests being run simultaneously.

Our water bowser was towed by an Instructor from the nearby Whitecliff 4×4 Centre, who was as skilled as he was amicable.

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.

Desktop Study – London Borough of Hammersmith and Fulham

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Desktop Study – London Borough of Hammersmith and Fulham

Southwest Environmental Limited were commissioned to undertake a Desktop Study in the London Borough of Hammersmith and Fulham. Hammersmith and Fulham is to the west of central London. Sub regions include Fulham in the South, Hammersmith in the center and White City in the North. At the northern tip of the borough is Wormwood Scrubs Park.

The report to discharge a planning condition related to contaminated land. The planning permission was for a residential conversion of a garage. Typically with a garage (and we would not guarantee this) if the garage appears clean and does not show evidence of heavy use (leaking oils etc) we would likely recommend nothing more than a “watching brief”.

Band Riveting . . . a lost art, when a Coffee Mug costs 99p

However, in this instance the site had been used for “band riveting” which we had to google, because we didn’t know what band riveting was! Having had a read on the subject it would appear that the process involves the use of solder. . . ergo fluxes one would think.

Although we were content that this use would unlikely impact on the residents of the proposed dwelling that remained indoors, there was a risk that the garden area was contaminated from discarded solder and flux. However, we subsequently learnt that the proposed garden area used to be part of a neighboring residential plot, and there was no access to it during the time of this band riveting activity.

So in the end we recommended no further action and a watching brief. The report was submitted to the EHO for scrutiny it has been return with some minor amendments requested, and is now passed off.

Air Quality Impact Assessment Horsham, West Sussex

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Air Quality Impact Assessment Horsham, West Sussex

Southwest Environmental Limited were engaged to undertake an Air Quality Assessment in Horsham. Ordinarily we would undertake an Air Quality Assessment in support of a planning application. But in this instance we were engaged by a Housing Association to undertake an Air Quality Assessment for a proposed development adjacent to their property.

The Housing Association were concerned that dust and gaseous emissions from the proposed demolition and construction activities would impact on their residents health.

We had a great deal of support from the Environmental Health Officer at the District Council, who proved invaluable in ensuring  our documents were put before the right people.

When working against a planning application such as was the case here, the biggest problem is often getting you report (regardless of how valid the conclusions are) in front of anyone with power to act.

We were lucky in this instance that there were various conditions of planning which were left unfinished, and as such we were able to comment on these as they were discharged.

The Air Quality Assessment Focus on applicable management practices for dust mitigation, monitoring requirements and methods for both dust and gaseous emissions. The baseline air quality report which was submitted with the initial application was rather limited in scope despite being accepted as adequate. However, it proved useful as it provided an overview of available secondary air quality data for the area.

SWEL also undertook a Noise Impact Assessment at the same site.

Surface Water Drainage Strategy & Flood Warning and Evacuation Plan Tilbury

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Surface Water Drainage Strategy & Flood Warning and Evacuation Plan Tilbury

Southwest Environmental were instructed to undertake a Surface Water Drainage Strategy for a commercial development in the Port of Tilbury.

A few weeks after this initial instruction we were also advised to proceed with a Flood Warning and Evacuation Plan.

In both cases the key was  building up sufficient evidence in order to ascertain risks accurately, and then implement migratory measures and evacuation procedures based on those risks.

Flood Warning and Evacuation Plan

There has been historic flooding in Tilbury, and flood water can take many days to recede after an event. The flood defenses in Tilbury do provide a good level of protection but, it is important to consider over topping events.

Although the site should remain high during a flood it is thought, that workers may be isolated for a number of days. To that end a list of long life provisions was included in the Flood Warning and Evacuation Plan. Image from here.

Surface Water Drainage Strategy

The site is to be entirely covered in concrete surfaces, there is also wash water from the intended use that must be disposed of.

Surface Water and Foul Water systems were kept separate in the conceptual design, additional measures were taken to ensure that this was so, although changes to design were kept to a minimum.

The port has a complex private drainage system, and this was studied in deatil to suggest applicable options moving forward.

ciria_mitigation_indices

Surface water was disposed of to the Thames River (which runs through London) via the Open Botany Drainage Channel and Botany Sluice. Water Qaulity to the Thames was subject to new CIRIA Mitigation Indices (above).

Flood Risk Assessment Kent

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Flood Risk Assessment Kent

SWEL were instructed to undertake a Flood Risk Assessment for a proposed development in Romney Marsh, Kent. For a Residential Development.

The scheme saw the construction of 2 homes, on a site occupied by a dilapidated bungalow.

A Wider Variety of Flood Risk Data was Used to form an Opinion

Key the flood risk assessment was establishing the level of protection afforded by the coastal defenses in the area, we arranged to have data supplied on the sea defenses which showed they were in good condition and that they were gave an applicable protection level.

Advise was included on required attenuation volumes, and any special construction techniques.

The sequential test was a key part of the report. We include a sequential test in our flood risk assessment as standard. . .if it is required.

Sunlight Daylight Assessment Cornwall

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Sunlight Daylight Assessment Cornwall 

Acting on instruction from a client in Exeter, Southwest Environmental Limited have prepared a Sunlight and Daylight Assessment for a Site in Bude, Cornwall.

The report was to check impacts on an existing property. SWEL used the well established (and normally applied) BR209 assessment method to derive VSC and Daylight Values for neighboring windows.

All was found to be well and good. And the design was considering applicable given the context of sunlight and daylight.

The proposed building was 3 stories in height and was set back approximately 20 meters from the existing building which was though worst affected. The worst affected window experienced a 12% drop in day light, with the guide allowing for 20%.