Flood Risk Assessment – Seaton, Devon

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Flood Risk Assessment – Seaton

Acting on instruction from a local authority Southwest Environmental Limited are to carry out a flood risk assessment for a proposed car car in Seaton, Devon.

The site is within a very complicated area with regards to flooding with recording instances of sewer and river (fluvial) flooding. Owing to the site’s proximity to the sea the action of waves is also important, having to be assessed relevant to the quality of flood defences in the area.

As well as up to date flood data the data ordered also contained various historic data as per above. This is not the not, and is handy as it includes information on the location of sewer flooding.

Flood Risk

Desktop Study – Ealing, London

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Desktop Study – Ealing, London

Southwest Environmental have conducted a desktop study to appraise land contamination at a site in Ealing London, on behalf of a development company.

The site was empty, and currently unused. Histroic searches showed that the site used to be occupied by a cinema.

Although it was thought that there was low risk from contaminated from this use, there were concerns raised over the possible presence of asbestos, and the also the integrity of control measures applied to a sub station in one corner of the site. 

A site investigation was therefore recommended, soil sampling in the area adjcent to the electricy sub staion to test for PCBs and soil sampling else where to test for the presence of asbestos.

Desktop Study London

Flood Warning and Evacuation Plan – Tilbury Essex

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Flood Warning and Evacuation Plan – Tilbury Essex

Southwest Environmental typically include a basic flood warning and evacuation plan within our Standard Flood Risk Assessment Report. However, some times for large multi use developments, in high risk areas a more detailed report is needed.

These Flood Warning and Evacuation Plans have numerous objectives which are listed below:

  • To inform residents and / or site users of likely flood conditions, how deep, will it be fast flowing.
  • To explain the flood warnings issued by the Environment Agency and how to interpret these warning, and act upon them.
  • To describe the location of any safe refuge that may be included within the building. 

A safe refuge is an area assigned within a building that is set above the 1 ;1000 year flood level. Residents or employees can move to this higher area within the building in the event of a flood. They may have to remain in the safe refuge for a number of day so it is important that there is space and facilities available accordant with the anticipated number of occupants.

It was conditioned within the planning approval for the development that a list of provisions be included for the safe refuge store within the Flood Warning and Evacuation Plan, and this was provided based on MSN 1676 a specification for provision in life raft and life boats. Irrelevant equipment was omitted, but by following this guide it was thought a long lasting and useful collection provisions was established on site.

This particular project in Tilbury, Essex require two plans, one for residential site users and one for commercial users.

If you have requirements of this nature with regards to a planning application or a planning condition relating to Flood Warning and Evacuation Plans then please get in touch.

Contaminated Land Site Investigation – Epsom and Ewell

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Southwest Environmental have recent been commissioned to undertake a contaminated land  site investigation within the London borough of Epsom and Ewell. The site investigation was commissioned on Wednesday the 30th April, and work began on the 6th of May. Making for a very prompt start.

I addition to the soil sampling of a car park area, vapour monitoring was also undertaken in the existing building which is ear marked for conversion under the new permitted development rights.

Another riveting photo!

The samples are currently with the labs on a very quick 3 day turnaround meaning the draft (soils only) report will be issued just two weeks after commissioning.

Environmental Permit Application – Hereford

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Acting on instruction from a construction and demolition company based to the north of Hereford. Southwest Environmental are undertaking an environmental permit application for a SR2010No12 permit (Treatment of waste to produce soil, soil substitutes and aggregate) .

The application site is ideally situated and meet the criteria for a standard permit;

• 10 metres of any watercourse;
• 50 metres from any spring or well, or from any borehole not used to supply water for domestic or food
production purposes; and
• 50 metres from any well, spring or from any  borehole used for the supply of water for human
consumption.  This must include private water supplies.
• 250metres within the presence of Great Crested Newts, where it is linked to the breeding ponds of the
newts by good habitat.; 
• 50 metres of a site that has relevant species or habitats protected under the Biodiversity Action Plan
that the Environment Agency considers at risk to this activity.;. 
• 50 metres of a National Nature Reserve (NNR), Local Nature Reserves(LNR), Local Wildlife 
  Site (LWS), Ancient woodland or Scheduled Ancient Monument.

The application is under way, with fairly limited supporting documentation constituting and Environmental management System, and a Site Condition Report.

Flood Risk Assessment – Bristol

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Southwest Environmental Limited were commissioned to write a flood risk assessment to accompany a planning application.

SWEl were informed that that the site was within flood zone 1, and was at low risk of flooding from tides and rivers. However, there was a question with regards to surface water flooding.

Unlike most developments that see the introduction of built elements, with a subsequent decrease in attenuation, the proposal saw the introduction of large areas of woodland and meadow land which resulted in a 10% increase in attenuation.

Flood Risk Bristol

Daylight Assessment for Basement Flat – Haringey

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Daylight Assessment for Basement Flat – Haringey

SWEL were approached by a property company in Haringey, London, to undertake an assessment of daylighting in an existing basement flat, with a view to making improvements to to increase daylighting.

A recommended level (ADF) of 1.5% is given for living areas, and the calculated ADF for the living area was around 0.25%.

The existing basement had an open sky angle of around 19 degrees, and an obstruction angle of 50 degrees. A report was published to suggest improvements that saw calculated ADF raised to 1.6%.

Sunlight and Daylight Assessment

Contaminated Land Site Investigation – Newton Abbot

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Southwest Environmental had previously carried out a Phase 1 Contaminated Land Desktop Study for a site in the Teign Valley. The site had been extensively worked as mine over the last 100 years or so, before being developed for residential use, probably around 40 years ago.

Soil sampling was undertaken using hand dug trial pits across the site, with a total of 10 sampling locations. Gas monitoring wells were also installed under the proposed extension foot print, ground water was close to the surface.

Sub soils conditions were varied, bedrock was encountered in the first 1 meter below ground level in some holes, whilst other were fill.

Plan Annotated During Field Work

We are awaiting results from the labs but there were no odorous materials detected during the ground investigation.

Site Investigation Devon

Phase 1 Desktop Study – Plymouth

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Acting on instruction from a developer in Plymouth, Southwest Environmental produced a phase 1 desktop study report for a planning application.

The site was on the city outskirts and had enjoyed an agricultural history. It was not foreseen that the land could be unduly contaminated and so its was recomedned that the site contamination assessment be arrested at this first phase.

An agricultural past with no buildings on site will nearly always mean low risk of harm resulting from site occupiers, although of course each site has to be assessed on an individual basis.

 Desktop Study Plymouth

Attenuation Tank Design – Surrey

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Following on from planning level reporting resulting in the conditioning of various surface water management requirements. Southwest Environmental are finalising design of surface water management system for a site in Surrey.

Design of attenuation tank in line with SUDs manual – Outflow requirements are negotiated with local sewer provider Thames Water, and tank capacity is adjusted to minimise capital outlay for developer.

Application is made to Thames Water for Sewer Connection. 

Note: The size of a surface water attenuation tank is based on the peak inflow rates from the site  (the run-off coefficient is taken it to account when calculating this), and the maximum outflow rate. For example a 5 litre per second outflow rate would require an attenuation tank size of 20 cubic meters, whilst a 10 litre per second out flow would require an 8 cubic meter attenuation tank.

As well as the attenuation tank design, a maintenance plan was submitted for it continued upkeep.